2008 AU Crops Cotton Research Report Research Report No. 33 March 2009 Alabama Agricultural Experiment Station Richard Guthrie, Director Auburn University Auburn, Alabama Printed in cooperation with the Alabama Cooperative Extension System (Alabama A&M University and Auburn University) ACKNOWLEDGMENTS This publication is a joint contribution of Auburn University, the Alabama Agricultural Experiment Station, and the USDA Agricultural Research Service and Soil Dynamics Laboratory. Research contained in the AU crops research reports was partially funded through the Alabama Cotton Commission, the Wheat and Feed Grains Committee, the Alabama Soybean Producers, and private industry grants. All donations, including the Alabama Cotton Commission grants and private industry funding, are appreciated. CONFIDENTIAL REPORT Publication, display, or distribution of data contained herein should not be made without prior written approval. Mention of a trademark or product does not constitute a guarantee of the product by Auburn University and does not imply its approval to the exclusion of other products. This report can be found on the Web at http://www.ag.auburn.edu/aaes/communications/researchreports/08cottonrr.pdf Information contained herein is available to all persons regardless of race, color, sex, or national origin. Published by the Alabama Cooperative Extension System (Alabama A&M and Auburn universities) in cooperation with the U.S. Department of Agriculture. An equal opportunity educator and employer. CONTENTS page Editors, Contributors ...........................................................................................................................................................................5 VARIETY TRIALS Enhancing Cotton Variety Selection through On-Farm Evaluations, 2008 ........................................................................................7 Breeding Cotton for Yield and Quality in Alabama ............................................................................................................................8 Economic Consequences of Using Different Cotton Variety Technology Systems in Alabama ........................................................9 Screening Trials for Cotton Variety Resistance to Verticillium Wilt ................................................................................................12 CROP PRODUCTION Benefits of Uniform Row Spacing in a Cotton-Corn Conservation System.....................................................................................13 Effect of Premature Defoliation on Cotton Yield and Lint Quality in Southwest Alabama .............................................................16 Agronomic and Economic Impact of Timing for Planting and Defoliation of Cotton on Cotton Yield, Quality, and Profitability ................................................................................................................................17 Evaluation of a CORS for Use by Alabama Producers.....................................................................................................................20 Evaluation of Variable-Rate Seeding for Cotton...............................................................................................................................21 The Old Rotation (circa 1896) – 2008 ..............................................................................................................................................22 The Cullars Rotation (circa 1911) – 2008 .........................................................................................................................................24 Impact of Crop Rotation on Diseases and Nematode Pests of Cotton, Corn, and Peanut as well as on the Economics of Cotton, Corn, and Peanut Production .....................................................................................25 IRRIGATION Sprinkler Irrigation for Site-Specific, Precision Management of Cotton .........................................................................................27 Subsurface Drip Irrigation Fertigation for Site-Specific, Precision Management of Cotton ............................................................28 Evaluating Pressure Compensating Subsurface Drip Irrigation for No-Till Row Crop Production on Rolling, Irregular Terrain......................................................................................................................................................29 FERTILITY Cotton Soil Fertility on Alabama Black Belt Soils ...........................................................................................................................31 Alternative Nitrogen Sources for Cotton ..........................................................................................................................................34 INSECT MANAGEMENT Effectiveness of Different Insecticides in Controlling Spider Mites and Aphids Infesting Cotton ..................................................35 Stink Bug Residual Control with Varying Classes of Chemistry......................................................................................................36 Stink Bug Threshold Verification Trial (Late Planting Date) ...........................................................................................................37 Stink Bug Threshold Verification Trial (Normal Planting Date) ......................................................................................................38 Systems Technology Trial, Prattville, Alabama ................................................................................................................................39 Systems Technology Trial, WREC, Headland, Alabama ..................................................................................................................40 WEED MANAGEMENT Evaluation of Herbicides for Palmer Amaranth Control in Cotton, Headland, Alabama 2008 ........................................................41 Residual Influence of Primary Tillage on Weed Control and Cotton Yield ......................................................................................42 Early Season Pigweed Control in Conservation Tillage Cotton .......................................................................................................43 DISEASE MANAGEMENT Evaluation of Seed Treatment Combinations with Seed Quality for Seedling Disease Management in Cotton in North Alabama, 2008 ............................................................................................................................................................45 Efficacy of Experimental Compounds on the Fusarium Wilt Complex in Central Alabama, 2008 .................................................46 Efficacy of Experimental Compounds on Early Season Cotton Diseases in North Alabama, 2008 ................................................48 Efficacy of Combination Seed Treatments on Early Season Cotton Diseases in North Alabama, 2008 ..........................................51 Evaluation of the Experimental Compound V-10116 on Early Season Cotton Diseases in North Alabama, 2008 .........................52 CONTENTS, CONTINUED DISEASE MANAGEMENT, CONTINUED Evaluation of the Experimental Compound V-10190 on Early Season Cotton Diseases in North Alabama, 2008 .........................54 Evaluation of the Experimental Compound V-10208 on Early Season Cotton Diseases in North Alabama, 2008 .........................55 Evaluation of Cotton Seedling Disease Management in North Alabama, 2008 ...............................................................................56 NEMATODE MANAGEMENT Performance of Selected Cotton Varieties against the Root-Knot Nematode in Central Alabama, 2008.........................................57 On-Farm Field Trials to Test the Effectiveness of Seed Nematacides for Managing Reniform and Root-Knot Nematodes on Cotton in Alabama ....................................................................................................................58 Cotton Response to Nemout® For Reniform Nematode Management in South Alabama, 2008 ....................................................59 Evaluation of Aeris Seed Treatment for Reniform Nematode Management in Cotton in North Alabama, 2008 ............................60 Evaluation of Experimental Seed Treatment Combinations for Reniform Nematode Management in Cotton in North Alabama, 2008 ............................................................................................................................................61 Evaluation of Experimental Nematicide Seed Treatments for Reniform Nematode Management in Cotton in North Alabama, 2008 ............................................................................................................................................63 Evaluation of Starter Fertilizer as a Means for Reniform Nematode Control in South Alabama, 2008 ..........................................65 Evaluation of Starter Fertilizer as a Means for Reniform Nematode Control in North Alabama, 2008 ..........................................66 Evaluation of Aeris Seed Treatment and Granular Nematicides for Reniform Nematode Management in South Alabama, 2008 ............................................................................................................................................................67 Evaluation of Experimental Biological Nematicide Seed Treatments for Reniform Nematode Management in Cotton in South Alabama, 2008 ............................................................................................................................................68 Evaluation of Cotton Seed Treatment and Granular Nematicides for Reniform Nematode Management in South Alabama, 2008 ............................................................................................................................................................70 Evaluation of Experimental Nematicide Seed Treatments for Reniform Nematode Management in Cotton in South Alabama, 2008 ............................................................................................................................................72 Cotton Cultivar Response to Root-Knot Nematodes in Two Tillage Regimes, 2008 .......................................................................74 Contributors Index ............................................................................................................................................................................75 EDITORS K. S. Lawrence Associate Professor Entomology and Plant Pathology Auburn University C. D. Monks Professor and Extension Specialist Agronomy and Soils Auburn University D. P. Delaney Extension Specialist IV Agronomy and Soils Auburn University CONTRIBUTORS A. Abdelgadir Technician IV Biosystems Engineering Auburn University J. R. Akridge Director Brewton Agricultural Research Unit Brewton, Alabama F. J. Arriaga Affiliate Assistant Professor Agronomy and Soils, Auburn University USDA-National Soil Dynamics Lab. K. S. Balkcom Affiliate Assistant Professor Agronomy and Soils, Auburn University USDA-National Soil Dynamics Lab. J. Bergtold Former Affiliate Assistant Professor Agronomy and Soils, Auburn University USDA-National Soil Dynamics Lab. W. C. Birdsong Regional Agronomist Southeast Alabama Alabama Cooperative Extension System K. L. Bowen Professor Entomology and Plant Pathology Auburn University C. Brodbeck Engineer II Biosystems Engineering, Auburn University C. H. Burmester Extension Agronomist Tennessee Valley Research and Extension Center, Belle Mina, Alabama H. L. Campbell Research Associate Entomology and Plant Pathology Auburn University J. D. Castillo Gradutate Research Assistant Entomology and Plant Pathology Auburn University J. Clary Regional Extension Agent, retired Alabama Cooperative Extension System L. M. Curtis Professor and Extension Spec., Emeritus Biosystems Engineering, Auburn University D. P. Delaney Extension Specialist IV Agronomy and Soils, Auburn University B. Dillard Regional Extension Agent Alabama Cooperative Extension System M. P. Dougherty Assistant Professor Biosystems Engineering, Auburn University B. Durbin Director, Field Crops Unit, E.V. Smith Research Center Shorter, Alabama J. P. Fulton Assistant Professor Biosystems Engineering, Auburn University W. S. Gazaway Professor and Extension Spec., Emeritus Entomology and Plant Pathology Auburn University R. W. Goodman Associate Professor Agricultural Economics and Rural Sociology Auburn University A. K. Hagan Professor Entomology and Plant Pathology Auburn University M. H. Hall Extension Specialist, Renewable Fuels Alabama Cooperative Extension System T. Harbuck Gradutate Research Assistant Biosystems Engineering Auburn University D. H. Harkins Assistant Director Tennessee Valley Research and Extension Center, Belle Mina, Alabama J. Holliman Director, Black Belt Research and Extension Center, Marion Junction, Alabama G. Huluka Associate Professor Agronomy and Soils, Auburn University J. Jones Assistant Director, Gulf Coast Research and Extension Center Fairhope, Alabama T. S. Kornecki Affiliated Associate Prosessor USDA-National Soil Dynamics Lab. L. Kuykendall Regional Extension Agent Autauga County Alabama Cooperative Extension System G. W. Lawrence Entomology and Plant Pathology Mississippi State University K. S. Lawrence Associate Professor Entomology and Plant Pathology Auburn University P. L. Mask Assistant Director, Ag, For, and Nat. Res. Alabama Cooperative Extension System B. Meyer Corporate Agronomist Alabama Farmers Cooperative Decatur, Alabama C. C. Mitchell Professor and Extension Agronomist Agronomy and Soils, Auburn University C. D. Monks Professor and Extension Specialist Agronomy and Soils, Auburn University CONTRIBUTORS, CONTINUED S. R. Moore Graduate Research Assistant Entomology and Plant Pathology Auburn University S. Nightengale Director, Plant Breeding Unit E. V. Smith Research Center Tallassee, Alabama B. E. Norris Director Tennessee Valley Research and Extension Center, Belle Mina, Alabama S. H. Norwood Regional Agent, Tennessee Valley REC Alabama Cooperative Extension System B. Ortiz Assistant Professor and Extension Spec. Agronomy and Soils, Auburn University M. G. Patterson Professor Agronomy and Soils, Auburn University M. Pegues Associate Director Gulf Coast Research and Extension Center, Fairhope, Alabama R. Petcher Regional Extension Agent Washington County Alabama Cooperative Extension System A. J. Price Affiliate Assistant Professor Agronomy and Soils, Auburn University USDA-National Soil Dynamics Lab. R. L. Raper Affiliated Professor Agronomy and Soils, Auburn University USDA–National Soils Dynamic Lab T. Reed Extension Specialist Tennessee Valley REC Alabama Cooperative Extension System N. S. Sekora Graduate Research Assistant Entomology and Plant Pathology Auburn University E. Schavey Regional Extension Agent Tennessee Valley Research and Extension Center Alabama Cooperative Extension System E. Schwab Engineering Technician USDA-National Soil Dynamics Lab. J. N. Shaw Professor Agronomy and Soils, Auburn University N. Silvey Sales Agronomist Madison County Cooperative R. H. Smith Professor and Extension Spec., Emeritus Entomology and Plant Pathology Auburn University D. B. Weaver Professor Agronomy and Soils, Auburn University A. Winstead Regional Agent, Tennessee Valley REC Alabama Cooperative Extension System R. P. Yates Regional Extension Agent Marengo County Alabama Cooperative Extension System VARIETY TRIALS ENHANCING COTTON VARIETY SELECTION THROUGH ON-FARM EVALUATIONS, 2008 C. D. Monks, C. H. Burmester, W. C. Birdsong, and R. W. Goodman On-farm cotton variety trials were initiated in 2008 in the following Alabama counties: Barbour, Cherokee, Elmore, Fayette, Macon, Shelby, and Mobile. As was the case in 2007, the objective was to compare and evaluate the performance of Roundup Ready Flex, Bollgard II/Widestrike, and conventional varieties. This was an effort to evaluate new releases for their potential as a replacement of current glyphosate and insect resistant technologies (i.e., DP 555 BG/RR) in 2010. Participating seed companies for the Flex trials included Delta and Pine Land, Stoneville, FiberMax, and Phytogen. Varieties included in the conventional trial in Macon County in- cluded Bronco, Seed Tec, DPL, and Phytogen. The number of entries in the trials was reduced when compared to earlier years to allow for more uniform test sites and replication where possible. The prevailing environmental conditions in 2008 were much more favorable when compared to the previous two years except for Cherokee County (not harvested). All trials were successfully initiated in April and May and harvested for yield. All locations resulted in yields that were suitable for yield and fiber comparisons. Yield and fiber quality data are now available through the Alabama crops website at www.alabamacrops.com. REGIONAL AGENTS BY LOCATION County Barbour Cherokee Cherokee and Fayette Elmore and Macon Mobile Shelby and Fayette Regional agent B. Dillard D. Derrick E. Schavey L. Kuykendall R. Petcher W. Griffith 8 ALABAMA AGRICULTURAL EXPERIMENT STATION BREEDING COTTON FOR YIELD AND QUALITY IN ALABAMA D. B. Weaver There are four major aspects to this project: (1) development of cotton germplasm or cultivars with improved yield and fiber properties, (2) evaluation and development of cotton germplasm for resistance to reniform nematode, (3) evaluation and development of cotton germplasm for resistance to abiotic stresses, particularly heat and drought, and (4) evaluation of the effect of exotic germplasm introgression on cotton yield and fiber properties. For the first objective, experimental breeding lines from several different cotton populations were developed using bulk and pedigree methods. In 2008, 80 experimental lines were evaluated for yield and fiber properties at two locations: Tallassee and Prattville. Plots were two rows, 6.1 m in length, with a spacing of 1 m between rows, replicated three times. Data were collected by sampling 50 bolls from each plot for determining lint percentage, boll size, lint weight per seed, and fiber quality. Fiber quality was analyzed by HVI at Cotton Inc., Cary, NC. The entire plot area was spindle-harvested to determine seed and lint yield. Good data were collected at both locations, and yield and fiber data analysis is in progress. Complete yield and fiber quality data are now available from the 2007 Regional Breeders Testing Network at 10 locations across the Cotton Belt. Auburn experimental lines ranked 4th, 5th, and 14th in the 32-entry test (29 experimental lines plus three checks). We have cooperated in this test for the past seven growing seasons. Five advanced lines were evaluated in the Regional Breeders Testing Network at 12 locations across the Cotton Belt in 2008. Data collection is still in progress. Further work is being done to develop new populations for generating experimental cotton lines for future testing. New crosses were made in the field in 2008, and F2 and F3 generations from crosses made in previous years were grown. Single plants were harvested from F3 populations and will be used to generate lines for testing in future years. We have made significant progress developing advanced populations from crosses between four adapted lines (FM966, SG747, PM1218, and Delta Pearl) and two germplasm lines (TX245 and TX1419) identified as having a moderate level of resistance to reniform nematode. Three types of populations have been developed: adapted × resistant accession (F2:4 lines); (adapted × resistant accession) × adapted (BC1:3 lines); and (adapted × resistant accession) × resistant accession (BC1:3 lines). We grew a total of 1200 lines representing 25, 50, and 75 percent adapted germplasm and increased these in the field in 2008. We have begun the evaluation of these lines for nematode resistance in greenhouse tests and evaluation will continue into 2009. Because of extreme variation we have altered our evaluation procedures to include 10 plants per line, so we are able to evaluate about 20 lines every two weeks. Evaluation and incorporation of genes for resistance into adapted types will be a long-term process. We are continuing along the same path in development of similar type populations using genotypes identified as heat tolerant. We have identified seven accessions as having significantly greater vegetative heat tolerance than Deltapine 90 and have demonstrated a relationship between chlorophyll fluorescence following heat stress and vegetative heat tolerance among these selected accessions. Development of these populations is progressing more slowly, due to the difficulty of crossing with these materials. These lines are photoperiodic, with long juvenile periods and can take more than a year between planting and flowering. We were able to make crosses in the greenhouse in spring of 2007 and grew the F1 plants during summer and early winter of 2008. We have begun to harvest F2 seeds from these plants from at least three of the population, and more have produced bolls that will be harvestable in late winter and spring of 2009. These F2 populations, along with the parental lines, will be used to determine heritability of the chlorophyll fluorescence trait and to further establish the relationship between chlorophyll fluorescence and vegetative heat tolerance. During the upcoming year, we will continue to work with these lines to determine the level of expression of this trait and to identify genes that are responsible. For our fourth objective, using materials described above in the reniform nematode work, we have developed a series of 120 advanced lines [8 populations, each with 15 lines (five lines each at 25, 50, and 75 percent adapted germplasm)] to study the effect of exotic (unadapted) germplasm on yield and fiber quality of upland cotton. Lack of genetic progress in cotton has been at least partially ascribed to a very narrow genetic base, and the purpose of this research is to assess the impact that exotic germplasm has on cotton yield and fiber properties and to determine if genetic variation can be improved by introgression of exotic lines. We plan to evaluate these materials in the field at two locations in 2009. 2008 AU CROPS: COTTON RESEARCH REPORT 9 ECONOMIC CONSEQUENCES OF USING DIFFERENT COTTON VARIETY TECHNOLOGY SYSTEMS IN ALABAMA T. Reed, C. H. Burmester, and C. D. Monks A test was conducted at the Tennessee Valley Research and Extension Center (TVREC) at Belle Mina and at the E.V. Smith Research Center (EVSRC) at Shorter to evaluate the economic consequences of using different cotton variety technology systems. Cotton was planted at TVREC on April 22 and at EVSRC on April 23 in 40-inch rows with 4.5 seed per row foot. Varieties planted at both locations were Stoneville 4554 B2RF (ST) (Bayer Crop Science), Phytogen 485 WF (PHY) (Dow AgroSciences LLC), and a conventional variety CT 210 (CT ) (Seed Tech Genetics). Temik 15G was applied in-furrow at TVREC and Temik 15G + Terraclor Super X was applied in-furrow at EVSRC. The experimental design was a split split-plot with varieties being the main plot variable. The main plots were then split by pre-emergence weed control. Half the plots at TVREC received Cotoran 4L + Prowl H2O at planting. Half the plots at EVSRC received Cotoran and Prowl + Roundup. All herbicides used and their costs are shown in Tables 1 and 2. The second split was by Heliothine (bollworm/budworm) control with larvicides for Heliothine control compared to plots without larvicides. At TVREC half the CT plots received applications for Heliothines on three occasions when treatment thresholds were reached (two Belt + one Brigade spray). A Brigade overspray was made to half the biotech variety plots on July 30 when Heliothine egg/larval counts exceeded the treatment threshold in the CT plots. At EVSRC applications for Heliothines were applied to half of all the plots each time the economic threshold was reached in the conventional variety plots. There were a total of four Heliothine sprays at EVSRC: twice with Tracer, once with Tracer + Asana, and once with Steward + Mystic. Plant bugs in plots without larvicides were controlled using three sprays at TVREC and five sprays at EVSRC. Plots at TVREC were rated for vigor on May 29, and plant stand counts were made on May 30. Plant height was measured at TVREC on June 30 and October 14. Plots were harvested on October 13, and cotton was ginned to determine percent lint. Cotton was classed at the Birmingham classing office. Staple, strength, and uniformity characteristics were measured. This information was used in completing the economic analysis. In the technology systems comparison, CT initially grew slower than the two biotech varieties at TVREC. TVREC plots were rated for vigor using a scale of 1 to 5 with 5 being the best possible rating. There was a significant difference in vigor rat- ings (Pr>F = 0.0012) in late May. The average vigor rating for CT was 2.44 while the two biotech variety vigor ratings averaged 3.1 (LSD 0.10 = 0.3). The effect of technology level on cotton plant height in June is shown in Table 3. There was a significant variety × herbicide × larvicide interaction with respect to October plant height (Pr>F = 0.0102) at TVREC. CT plots without PREs and without larvicides averaged 50.8 inches while CT plots that received one or both of these treatments averaged from 43 to 43.9 inches. ST and PHY plots treated with different combinations of PREs and larvicides had average heights ranging from 39.8 to 46.4 inches (LSD 0.10 = 3.3). Stand counts made at TVREC on May 30 showed there were significantly fewer plants (Pr>F = 0.0062) per 20 row feet in the ST plots (63.7) and CT plots (64.7) than in the PHY plots (72.9) (LSD 0.10 = 5). There was a significant difference in yield among varieties at both TVREC (Pr>F = 0.0001) and EVSRC (Pr>F = 0.0015). There was a significant variety × larvicide treatment response with respect to yield at both TVREC and EVSRC (Table 4) with CT benefiting from Heliothine control at both locations and PHY benefiting from larvicides at TVREC. ST and PHY with and without larvicide yielded significantly more cotton than CT plots, regardless of larvicide treatment or location. There was no significant difference in ST and PHY with-larvicide and without-larvicide plots at TVREC. ST plots did not respond to larvicide sprays. A pyrethroid applied on July 30 significantly increased the PHY yield at TVREC; however, larvicide treatment at EVSRC did not increase PHY yield. Larvicide applications increased CT yield 498 pounds per acre at TVREC and 298 pounds per acre at EVSRC. There was also a significant variety × herbicide interaction with respect to yield at TVREC with CT 210 yielding significantly more cotton when pre-emergence herbicides were used (Table 5). Tables 6 and 7 show the results of the economic analysis for the 12 variety/larvicide/herbicide combinations at TVREC and EVSRC. Loan values ranged from 52.3 to 54.45 cents per pound at TVREC and from 53.55 to 54.35 cents per pound at EVSRC. The CT plots without pre-herbicides and without larvicides netted the least return after selected expenses were considered at both locations. ST plots with a pre-herbicide and without larvicides netted the highest return at both locations. 10 ALABAMA AGRICULTURAL EXPERIMENT STATION TABLE 1. DATE OF APPLICATION AND COST OF HERBICIDES USED AT TVREC - 2008 Herbicide Cotoran 4L Prowl H2O Glyphosate Dual Staple Select Glyphosate Staple Glyphosate Envoke Valor MSMA Total Cost/$3 1 Date applied 4/22 4/22 5/29 5/29 5/29 5/29 6/9 6/9 6/26 6/26 7/8 7/8 2 Rate/acre Cost/acre/ $ 2 pt 10.00 1 pt 4.50 2 pt 9.00 1 pt 13.13 2 oz 13.00 10 oz 14.00 2 pt 9.00 2 oz 13.00 2 pt 9.00 0.1 oz 7.50 2 oz 8.26 2 pt 5.00 CT 210 Pre B 1, G G2 CT 210 no Pre ST 4554 B2RF Pre B-G G B G B B G 41 B B G 48 ST 4554 PHY 485 B2RF WRF no Pre Pre B-G G B-G G B-G B-G PHY 485 WRF no Pre B-G G B-G B-G B G 37 B G 44 B G 37 B G 44 B = Broadleaf weeds. G = Grass. 3 Rounded to the neared $. TABLE 2. DATE OF APPLICATION AND COST OF HERBICIDES USED AT EVSRC - 2008 Date Herbicide applied Roundup(RU) 3/24 Cotorran 4L 4/24 Prowl 3.3 EC 4/24 RU 4/24 RU WMax 5/21 Parrlay 5/21 Staple 5/21 Poast+ 5/21 RU WM 5/30 Envoke 5/30 Caparol 6/17 MSMA 6/17 Total Cost/$3 1 Rate/acre Cost/acre/ $ 1.5 pt 10.88 2.0 pt 10.00 2.0 pt 8.00 1.5 pt 10.88 22 oz 11.69 1.3 pt 12.47 2.0 oz 13.00 2.25 pt 16.00 2 2 oz 11.69 0.1 oz 7.50 1.5 pt 3.75 2.5 pt 6.25 CT 210 Pre B1-G2 B G B-G CT 210 no Pre B-G ST 4554 B2RF Pre B-G B-G G B G B B-G G 57 B B-G G 58 ST 4554 PHY 485 B2RF WRF no Pre Pre G-G B-G B-G G B-G B-G B B-G B-G G 56 B-G B-G G 61 PHY 485 WRF no Pre B-G B-G B-G G B-G B-G G 56 B-G B-G G 61 B = Broadleaf weeds. 2 G = Grass. 3 Rounded to the neared $. TABLE 3. EFFECT OF TECHNOLOGY LEVEL ON COTTON PLANT HEIGHT (JUNE) AT TVREC, 2008 Technology variety Treatment PHY 485 WRF ST 4554 B2RF CT 210 LSD (0.10) Cotoran + Prowl, Pre No Pre LSD (0.10) Plant height in. 21.0 a 19.7 b 17.2 c 1.2 20.0 a 18.6 b 1.0 TABLE 4. EFFECT OF VARIETY AND LARVICIDE TECHNOLOGY ON COTTON YIELD, 2008 Variety ST 4554 ST 4554 PHY 485 PHY 485 CT 210 CT 210 LSD (0.10) Technology larvicide None Treated None Treated None Treated ——Lint yield (lb/A)—— TVREC EVSRC 958 2196 1946 2117 1875 1899 1981 1819 1222 1232 1720 1530 86 90 Herbicide TABLE 5. EFFECT OF VARIETY AND HERBICIDE TECHNOLOGY ON COTTON YIELD AT TVREC, 2008 Variety Stoneville 4554 B2RF Phytogen 485 WRF CT 210 Conventional LSD (0.10) Herbicide Lint yield (lb/A) No Pre emergence 1696 Pre emergence 1674 No Pre emergence 1689 Pre emergence 1737 No Pre emergence 1235 Pre emergence 1394 86 2008 AU CROPS: COTTON RESEARCH REPORT 11 TABLE 6. NET RETURNS FOR THREE COTTON TECHNOLOGY SYSTEMS AT TVREC IN 20081 Variety ST ST ST ST PHY PHY PHY PHY CT CT CT CT 1 Pre-herbicide No No Yes Yes No No Yes Yes No No Yes Yes Larvacide No Yes No Yes No Yes No Yes No Yes No Yes Lint lb/A 1920 1995 1995 1896 1817 1999 1933 1964 1068 1704 1376 1731 Value/A $ 1042 1082 1079 1032 985 1081 1045 1062 578 923 720 941 Seed + tech fee cost/A2 77 77 77 77 75 75 75 75 20 20 20 20 2 Herbicide cost/A 44 44 37 37 44 44 37 37 48 48 41 41 Insecticide cost/A 26 28 26 28 26 28 26 28 26 64 26 64 Net $ 895 933 939 890 840 934 907 922 484 791 633 816 Abbreviations, ST, Stoneville 4554B2RF; PHY, Phytogen 485 WF; CT, CT 210. acres per bag of ST and PHY cotton seed and 4 acres per bag of CT seed. Seed plus tech fee cost per acre based on seeding rate of 4.6 TABLE 7. NET RETURNS FOR THREE COTTON TECHNOLOGY SYSTEMS AT EVSRC IN 20081 Variety ST ST ST ST PHY PHY PHY PHY CT CT CT CT Pre-herbicide No No Yes Yes No No Yes Yes No No Yes Yes Larvacide No Yes No Yes No Yes No Yes No Yes No Yes Lint lb/A 2173 2103 2220 2082 1805 1806 1951 1805 1234 1507 1332 1380 Value/A $ 1179 1140 1189 1125 976 982 1056 971 661 809 715 739 Seed + tech fee cost/A2 101 101 101 101 96 96 96 96 20 20 20 20 2 Herbicide cost/A 56 56 61 61 56 56 61 61 58 58 57 57 Insecticide cost/A 35 114 35 114 35 114 35 114 35 114 35 114 Net $/A 987 869 992 849 789 716 864 700 548 617 603 548 1 Abbreviations, ST, Stoneville 4554B2RF; PHY, Phytogen 485 WF; CT, CT 210. acres per bag of ST and PHY cotton seed and 4 acres per bag of CT seed. Seed plus tech fee cost per acre based on seeding rate of 4.6 12 ALABAMA AGRICULTURAL EXPERIMENT STATION SCREENING TRIALS FOR COTTON VARIETY RESISTANCE TO VERTICILLIUM WILT C. H. Burmester, K. S. Lawrence, E. Schavey, B. Meyer, and N. Silvey Verticillium wilt is a soilborne pathogen that can attack the root vascular system of cotton and cause premature cotton defoliation and death in certain cases. In cotton, resistant varieties are used as the primary method of control. In recent years, verticillium wilt has returned as a major factor reducing cotton yields in the northern areas of Alabama and into Tennessee. Several years ago the cotton variety ST5242 BR was identified as having resistance to verticillium wilt in this area. It has been planted on many acres but is currently being phased out as a commercial variety. Tests were conducted in 2007 and 2008 to identify possible replacement varieties of cotton that have resistance to the verticillium wilt in this area. Screenings were conducted in irrigated cotton fields with a history of verticillium wilt problems in 2007 and 2008. One row of each variety was planted across the length of the cotton field. Twenty four varieties were screened in 2007 and 30 varieties were screened in 2008. In early fall when verticillium wilt symptoms began appearing, ratings were conducted in four regions of the test area where uniform wilt symptoms were found. Cotton plants in ten row feet were counted and the number of plants with wilt symptoms was recorded. An overall rating of the severity of the wilt symptoms was made with 0 indicating no symptoms and 5 indicating severe symptoms. Overall the occurrences of wilt symptoms were much higher and more consistent in the 2008 test site than in the 2007 site (Table 1 and 2). The 2008 site also contained several new and experimental cotton varieties that will be available in 2009. Although no cotton variety had lower verticillium wilt ratings than ST5242 BR in 2008, several varieties indicated some possible wilt tolerance. Cotton varieties in 2008 with wilt ratings lower than ST5242 BR included DP0920 B2RF, DP0935 B2RF, DP161 B2RF, FM1740 B2RF, and ST4498 B2RF. Experimental cotton varieties STX 0721 B2RF, STX 0727 B2RF, and STX704 B2RF also indicated lower wilt ratings in 2008. These screening trials are only the first step in identifying possible replacement cotton varieties for this area of Alabama and Tennessee. On-farm cotton yield results will ultimately determine which cotton varieties have the yield and wilt resistance cotton farmers need in this area. TABLE 1. INCIDENCE OF VERTICILLIUM WILT AND VARIETY RATING ON TATE FARMS IN MADISON COUNTY, 2007 Variety DP117 B2RF DP141 B2RF DP143 B2RF DP161 B2RF DP445 BG/RR DP454 BG/RR DP455 BG/RR DP143 B2RF DP164 B2RF DPL117 B2RF FM9063 B2RF MX0610 B2RF MX0613 B2RF MX0616 B2RF PHY485 WRF ST4554 B2RF ST4427 B2RF ST4554 B2RF ST5242 BR 3 ST5327B2RF ST6611B2RF STX0626 B2RF STX0627 B2RF STX0630 B2RF 1 Average wilt % 7.7 5.3 16.6 15.2 14.9 8.3 3.4 22.7 8.1 11.5 8.8 29.6 10.9 16.8 17.4 8.0 26.3 9.0 10.8 10.1 7.1 14.4 17.8 12.5 1 Average wilt rating2 2.88 1.25 2.38 3.25 3.50 3.75 2.38 3.13 2.63 3.25 3.25 4.00 2.50 3.88 3.13 2.13 2.63 2.56 2.63 2.63 1.13 2.38 3.50 2.88 TABLE 2. INCIDENCE OF VERTICILLIUM WILT AND VARIETY RATING ON TATE FARMS IN MADISON COUNTY, 2008 Variety AFD5065 B2RF AM1550 B2RF CG3220 B2RF CG3520 B2RF DP0912 B2RF DP0920 B2RF DP0924 B2RF DP0935 B2RF DP141 B2RF DP143 B2RF DP161 B2RF DP445/RR DPLX07W903 DF DPLX07X440 DF FM1740 B2RF PHY375 WRF PHY485 WRF ST4498 B2RF ST4554 B2RF ST5242 BR 3 ST5242 BR 3 ST5327 B2RF ST5458 B2RF ST4427 B2RF STX0703 STX0705 STX0721 B2RF STX0727 B2RF STX702 B2RF STX704 B2RF 1 Four reps. 2 0 = no symptoms, 5 = severe. 3 Check variety. Average wilt1 % 29.8 43.5 37.0 41.4 42.3 30.4 25.7 22.9 35.1 36.0 29.3 24.8 30.7 25.0 25.4 34.6 53.8 22.1 26.4 46.5 25.9 37.8 39.8 34.8 40.0 34.7 24.6 27.3 44.1 38.0 Average wilt rating2 2.25 3.00 3.25 3.75 2.75 1.75 3.38 2.00 3.63 2.63 2.00 3.25 3.00 2.75 2.50 3.00 3.00 2.00 2.50 1.13 1.25 3.75 3.25 3.88 2.75 2.50 1.75 2.00 3.25 2.00 Four reps. 2 0 = no symptoms, 5 = severe. 3 Check variety. 2008 AU CROPS: COTTON RESEARCH REPORT 13 CROP PRODUCTION BENEFITS OF UNIFORM ROW SPACING IN A COTTON-CORN CONSERVATION SYSTEM R. L. Raper, K. S. Balkcom, F. J. Arriaga, A. J. Price, T. S. Kornecki, and E. B. Schwab Crop rotations are an important part of every conservation system. However, different crops have varying needs and much of the data for their growth was obtained in a monoculture. When these crops are integrated into a conservation system that minimizes surface disturbance, tillage practices may need to be further examined to choose the best solutions for both crops. Soil compaction in the southeastern region of the U.S. is extremely prevalent and routinely reduces crop yields unless inrow subsoiling is annually conducted. In 2006, an experiment was initiated at the E.V. Smith Research Center in Shorter, Alabama, to evaluate the effects of crop rotation, row spacing, and tillage practices on corn and cotton production systems. Soils at the site are mostly in the Compass series and are coarse-loamy, siliceous, subactive, thermic Plinthic Paleudults. The conservation system included a cover crop system which was crimson clover (Trifolium incarnatum L.) prior to corn, and rye (Secale cereale L.) prior to cotton. A dryland corn-cotton rotation was established at the site in the spring of 2007 with corn being planted on the eastern half of the plots either in 30- or 36-inch rows and cotton being planted on the western half of the plots in 36-inch rows. In 2008, the crops were rotated with cotton being planted on 36-inch rows in the previous corn plots and corn being planted either in 30- or 36-inch rows following the cotton in 36-inch rows. Plant populations were maintained at similar levels in both row spacings with cotton being planted with 45,000 seeds per acre and corn with 28,000 seeds per acre Additionally, four in-row subsoiling treatments were arranged within the experiment: (1) annual, (2) spring prior to corn, (3) spring prior to cotton, and (4) none. All of the plots were managed with conservation systems which used no surface tillage. The total number of plots in the experiment were 64 which were composed of two crops (corn and cotton) × two row spacings (30-inch and 36-inch corn) × four tillage treatments × four replications. Figure 1 illustrates how the row spacings were arranged with the first pass (center of tractor) of the cotton (2008) being positioned directly over the first pass (center of tractor) of corn (2007). All in-row subsoiling operations were conducted prior to planting with a KMC (Kelly Manufacturing Company) ripper bedder to an approximate depth of 16 inches. Subsoiling and planting operations were conducted with a Trimble AgGPS Autopilot® automatic steering system, which was capable of inchlevel precision. Soil strength measurements were obtained with the multipleprobe soil cone penetrometer system in the fall of the year after harvesting the cash crop. This machine acquired three sets of soil strength measurements across the row from which cone index values were calculated (ASAE Standards, 2004a; ASAE Standards, 2004b). Statistical analyses were performed on the split-plot experiment with row spacing as the main plots and the four different tillage treatments as the subplots. The split-plot experiment was analyzed with the appropriate ANOVA model using SAS. A predetermined significance level of P ≤ 0.10 was selected and Fisher’s least-significant-difference test (LSD) was used for mean separation. Due to space limitations, discussion will be limited to the significant main effects of the cone index measurements. During the 2007 growing season, no differences in crop yield were found nor were they expected as the benefits from controlled traffic would not be apparent until the second growing season. In 2008, corn yield showed a significant interaction between row spacing and tillage treatment (Figure 2) with the highest yields occurring in the 36-inch rows with the in-row subsoiling treatment being conducted prior to the previous cotton crop. Not statistically different were the 36-inch corn following annual in-row subsoiling, 36-inch corn following in-row subsoiling conducted prior to corn, and 30-inch corn following in-row subsoiling conducted prior to corn. These results were interesting and surprising as highest yields for this region are commonly thought to occur with the narrow row spacing of 30 inches. However, using controlled traffic with conservation systems and maintaining the rows in the same location (as well as the benefits from in-row subsoiling) increased corn yields with the 36 inch rows significantly. Additionally, no loss in benefits was found by in-row subsoiling almost one year previously before the cotton crop. Cotton yields in 2008 were affected only by tillage treatments (Figure 3) with the highest yields occurring with annual in-row subsoiling or with in-row subsoiling conducted just prior to the cotton crop (with both row spacings). No-tillage and inrow subsoiling conducted prior to the previous corn crop produced lower yields. These results indicated that cotton was more sensitive to soil compaction and required in-row subsoiling conducted just prior to establishment. The soil strength data provide further evidence of the benefits of in-row subsoiling conducted just prior to cotton establishment. Figure 4 shows the loosened row middles where the cotton roots are actively growing. Note the absence of intense soil compaction with the soil being loosened where the cotton roots are growing. Now compare this to the soil condition resulting from in-row subsoiling conducted the previous year before the corn crop (Figure 5). Intense soil compaction is shown near the row middles of the previous corn crop, probably resulting from vehicle traffic being conducted the previous growing season. Note especially the last cotton row, which was placed near a previous corn row middle with the roots attempting to grow in a compacted region. However, both soil conditions are superior to the no-tillage treatment where no deep tillage has been 14 ALABAMA AGRICULTURAL EXPERIMENT STATION conducted throughout the period of the experiment (Figure 6). In these plots, uniform compaction is prevalent throughout the entire growing region where row spacings are non-uniform. The following conclusions can be drawn: • Highest corn yields were found in the 36-inch rows, which differs from the commonly held belief that increased corn yields are obtained in our region with narrower row spacings of 30 inches. • Corn yields were not found to suffer from in-row subsoiling conducted almost a year previously before the cotton crop. • Cotton yields were found to benefit from in-row subsoiling conducted just prior to planting. • Soil strength information verified that intense soil compaction was found beneath a portion of the rows in the cotton plots that had previously been under the previous corn crop’s trafficked row middles. Annual Prior to Cotton 125 Corn Yield (bu/ac) Prior to Corn No-Tillage 100 75 50 25 0 30-in Corn bc abc c c ab ab a c 36-in Corn Figure 2. Corn yield in 2008 showing the effects of annual inrow subsoiling, no tillage, or in-row subsoiling prior to corn or cotton. Letters indicate statistical significance (LSD ≤ 0.10). Figure 1. Row spacings layout showing 30 inch corn spacings (bottom) and 36 inch cotton spacing (top). Annual Prior to Cotton Seed Cotton Yield (lb/ac) 3500 3000 2500 2000 1500 1000 500 0 a b Prior to Corn No-Tillage a b Figure 3. Cotton yield in 2008 showing the effects of annual in-row subsoiling, no tillage, or in-row subsoiling prior to corn or cotton. Letters indicate statistical significance (LSD ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 15 Figure 4. Cone index iso-profiles (MPa) for in-row subsoiling treatments conducted prior to cotton planting across the growing zone showing differences that were caused by vehicle traffic and in-row subsoiling for different row spacings (left) and similar row spacings (right). Figure 5. Cone index iso-profiles (MPa) for in-row subsoiling treatments conducted prior to corn planting across the growing zone showing differences that were caused by vehicle traffic and in-row subsoiling for different row spacings (left) and similar row spacings (right). Figure 6. Cone index iso-profiles (MPa) for no tillage treatments across the growing zone showing differences that were caused by vehicle traffic and in-row subsoiling for different row spacings (left) and similar row spacings (right). 16 ALABAMA AGRICULTURAL EXPERIMENT STATION EFFECT OF PREMATURE DEFOLIATION ON COTTON YIELD AND LINT QUALITY IN SOUTHWEST ALABAMA C. D. Monks, R. W. Goodman, M. Pegues, J. Jones, and R. Petcher The objective of this study was to investigate the impact that mid- to late-season leaf removal (i.e., hurricane damage) has on cotton yield and lint quality. This trial was conducted in 2006, 2007, and 2008 at the Gulf Coast Research and Extension Center in Fairhope (Tables 1, 2, and 3). Defoliation treatments began in mid-August when cotton maturity reached four to five nodes above white bloom and before cotton began opening. At this stage, there were no open bolls found in the plots. Subsequent defoliation was accomplished for each treatment on a weekly interval. Seed cotton yields were obtained approximately two weeks after each defoliation treatment was applied, and were then hand ginned. Turnout was either unaffected (2006) or lower when cotton was defoliated prior to opening. Micronaire was not affected in 2006 but was severely reduced in 2007 and 2008 by the early treatments. Fiber length was generally longer for the early application timings; however, fiber strength was less predictable. Lint yield was severely reduced in most years by early defoliation. Defoliation timing2 Turnout Trt. No. % 1 42 2 42 3 42 4 43 5 43 6 44 7 43 8 43 LSD (0.05) NS C.V. ( %) 1.9 Pr>F 0.1813 1 2 TABLE 1. EFFECT OF EARLY DEFOLIATION ON COTTON YIELD AND QUALITY, 20061 Lint yield lb/A 255 e 351 de 432 cd 463 bc 630 a 602 a 588 a 553 ab Above 12.5 0.0001 Mic. 3.1 3.9 4 4 4 3.3 4 4 NS 16.4 0.4516 Length Strength in g/tex 1.13 28.1 1.13 28.4 1.11 27.9 1.12 28.9 1.11 29.3 1.12 28.6 1.11 28.9 1.11 28.5 NS NS 1.6 3.6 0.5173 0.7191 Defoliation timing2 Turnout Trt. No. % 1 41 f 2 42 e 3 43 ab 4 44 bc 5 44 bc 6 45 a 7 44 ab 8 43 cd LSD (0.05) Above C.V. ( %) 1.4 Pr>F 0.0001 1 2 TABLE 2. EFFECT OF EARLY DEFOLIATION ON COTTON YIELD AND QUALITY, 20071 Lint yield lb/A 965 c 1121 bc 1342 ab 1477 a 1382 a 1426 a 1416 a 1427 a Above 11.5 0.0009 Mic. 3.1 d 3.5 c 4.1 b 4.4 b 4.3 b 4.7 a na 4.2 b Above 5.7 0.0001 Length Strength in g/tex 1.13 a 27.6 ab 1.12 ab 28 ab 1.11 abc 28.2 ab 1.11 abc 29 a 1.09 cd 27.6 ab 1.07 d 27.1 b na na 1.11 bc 28 ab Above Above 1.5 4 0.003 0.3717 Planting date: DP 555 BG/RR on May 8, 2006. First application date prior to boll opening: August 18, 2006. Planting date: DP 555 BG/RR on May 3, 2007. First application date prior to boll opening: August 16, 2007. Defoliation timing2 Trt. No. 1 2 3 4 5 6 7 8 LSD (0.05) C.V. ( %) Pr>F 1 2 TABLE 3. EFFECT OF EARLY DEFOLIATION ON COTTON YIELD AND QUALITY, 20081 Turnout % 41 b 41 b 41 b 43 a 43 a 43 a 43 a 43 a Above 1.8 0.0001 Lint yield lb/A 427 e 655 d 912 c 1160 b 1313 ab 1348 a 1327 a 1280 ab Above 9.1 0.0001 Mic. 2.7 d 2.7 d 3.1 c 3.6 b 3.9 a 4.0 a 4.0 a 4.1 a Above 5.2 0.0001 Length in 1.14 1.15 1.13 1.10 1.10 1.10 1.11 1.10 0.03 1.9 0.0169 Strength g/tex 27.4 bc 27.7 bc 29.0 a 28.4 ab 28.4 ab 27.2 c 29.1 a 27.7 bc Above 2.4 0.0061 Planting date: DP 555 BG/RR on May 8, 2008. First application date prior to boll opening: August 18, 2008. 2008 AU CROPS: COTTON RESEARCH REPORT 17 AGRONOMIC AND ECONOMIC IMPACT OF TIMING FOR PLANTING COTTON ON COTTON YIELD, QUALITY, AND PROFITABILITY J. Bergtold, C. D. Monks, K. S. Balkcom, R. Raper, and F. J. Arriaga AND DEFOLIATION OF This experiment was initiated in the fall of 2006 at the E.V. Smith Research Center, Field Crops Unit near Shorter, Alabama, on a Compass sandy loam (coarse-loamy, siliceous, subactive, thermic Plinthic Paleudults). The experiment was rotated to a different location each year, but the soil type was the same. The experimental design contained a strip-plot treatment restriction in a randomized complete block design with three replicates. All plots were 24 feet wide and 75 feet long in 2007 and 50 feet long in 2008. The horizontal plots consisted of three planting dates, and the vertical plots were defoliation times that corresponded to 40, 60, 80, and 100 percent open boll. A rye cover crop was drilled across the experimental area each fall at 90 pounds per acre. An in-row subsoiling operation was performed, prior to each planting date, with a KMC (Kelly Manufacturing Company) Rip Strip®. A starter fertilizer application was applied across the experimental area to supply 40 pounds N per acre, 11 pounds P2O5 per acre, and 40 pounds K2O per acre. Cotton (DPL 454BG/ RR®) was planted (73,000 plants per acre) in 36-inch rows with an in-furrow application of Temik® (7 pounds per acre) and Terraclor® (10 pounds per acre). Nitrogen applied as a UAN solution at 70 pounds per acre was sidedressed by early square for each planting date. A POST application of Roundup® (1.5 pints per acre) was applied for each planting date at the fourleaf stage, followed by a layby application of Roundup® (1.5 pints per acre) + Caparol® (1.5 pints per acre). For each defoliation time, all corresponding cotton plots were defoliated with Def 6® (8 ounces per acre), and Dropp® (3 ounces per acre). Four rows of the subsequent plots were harvested with a spindle picker equipped with a bagging attachment approximately two weeks following defoliation. A large sub-sample (approximately 50 pounds) was sent to the University of Georgia’s Micro-Gin Facility to determine ginning percentages. After the ginning process, another sub-sample of the lint from each plot was sent to the USDA Classing office in Macon, Georgia, to determine cotton quality from all plots with HVI-fiber analysis. Initial plant populations were recorded approximately four weeks after each planting date by counting all the plants from four 5-foot sections across four harvest rows within each plot. Final plant heights were recorded from 20 plants per plot (five per harvest row) just prior to defoliation. All response variables were analyzed using the MIXED procedure (Littell et al., 2006) and the LSMEANS PDIFF option to distinguish between treatment means (release 9.2; SAS Institute Inc., Cary, NC). Data were analyzed by year with planting date, defoliation time, and their interactions as fixed effects in the model, while replication, replication × planting date, and replication × defoliation time were considered random. Treatment differences were considered significant if P ≤ 0.05. Plant Populations. In 2007, plant populations were influenced by the planting dates (Pr> F = 0.0004). The plant populations were 45,400, 37,900, and 67,000 plants per acre for planting dates 1, 2, and 3, respectively. These values reflect the climate for the 2007 growing season. Early spring weather was cool, which certainly would affect cotton germination, followed by extremely dry weather. The dry weather forced seeding cotton for the second planting date to be planted in dry soil. No rainfall occurred after the second planting date, and cotton did not germinate until the field was irrigated approximately three weeks later. As a result, the lowest plant populations were recorded from the second planting date. Excellent planting conditions and subsequent moisture resulted in the highest plant stands recorded for the third planting date. In 2008, the growing season was much cooler initially, which delayed all three planting dates. However, differences among the plant populations were observed and as the planting dates progressed, the subsequent plant populations increased. Plant populations were 42,800, 50,500, and 57,300 for planting dates 1, 2, and 3, respectively. Plant Heights. No differences were observed among plant heights for the three planting dates of the 2007 growing season (Pr> F = 0.2430). Plant heights averaged 41, 43, and 40 inches tall for planting dates 1, 2, and 3, respectively. However, plant heights measured during the 2008 growing season were affected by planting dates (Pr> F = 0.0002). Plant heights in 2008 averaged 43, 55, and 46 inches tall for planting dates 1, 2, and 3, respectively. The much taller plants observed for the second planting date can be attributed to above average rainfall that stimulated vegetative growth. The wet soil conditions did not allow for timely growth regulator applications. Cotton Yields. As previously mentioned, extreme cool weather at the beginning of the 2008 growing season pushed all the planting dates back approximately 1 month. This delay combined with cool weather in early fall of 2008 did not allow for cotton harvest of the third planting date. In addition, only seed cotton values are available for the first and second planting dates of the 2008 growing season. However, there was an interaction between planting dates and defoliation dates (Pr > F = 0.0507) for the 2008 seed cotton yields as illustrated in Figure 1. Seed cotton yields from the first planting date were numerically higher than values from the second planting date with the exception of the 100 percent defoliation time. Yields from the 100 percent defoliation of the first planting date 1 were significantly lower than the 40 percent and 80 percent defoliation times of the first planting date. Seed cotton yields from the second planting date were equivalent across defoliation times, but the 40 percent and 80 percent defoliation dates for the second planting date were lower than yields from the 80 percent defoliation of the first planting date. At this time, a complete data analysis that includes fiber quality is only available for the 2007 growing season. This analysis will focus on lint, length, micronaire, strength, and uniformity with the means across treatments presented in the table. 18 ALABAMA AGRICULTURAL EXPERIMENT STATION An interaction (Pr> F = 0.0003) was observed between planting dates and defoliation percentages for cotton lint yields (Figure 2). This interaction can be attributed to 33 percent lower lint yields measured from the second planting date compared to the first and third planting dates. The lower lint yields for the second planting date resulted from dry conditions at planting, which suppressed cotton emergence and subsequent growth. In addition, cotton lint yields were more variable across the different defoliation percentages from the first planting date compared to lint yields across defoliation percentages for the third planting date (Figure 2). These yields indicate that for early planted cotton, there may be a yield advantage to defoliating the cotton slightly later. Fiber Quality. Length, micronaire, and strength were only affected by planting date in 2007, but planting date affected the fiber properties differently (see table). The first planting date produced the longest fibers followed by the third and second planting dates. This indicates that cotton from the first planting date was not stressed as much as cotton in the other planting dates. On the other hand, micronaire values for the first planting date were in the discount range for low micronaire. This would indicate more immature bolls at cotton harvest. This is supported by the lower gin turnout for this planting date (data not shown). Micronaire values for the second planting date were in the premium range, but due to low yields, this seems more due to chance. The highest micronaire values were for the third planting date; they were just below the discount range for high micronaire. Fiber strength values were equivalent for the first and second planting dates, but approximately 10 percent greater for the third planting date. Uniformity values for different defoliation percentages within each planting date were not consistent, which resulted in an observed interaction (Pr> F = 0.0392) across planting dates and defoliation percentages (Figure 3). Although uniformity values were not below discount thresholds, the third planting date produced higher uniformity values. Uniformity values for the third planting date were superior to at least one of the other planting dates across most of the defoliation times. In conclusion, one year of data collection for fiber properties that were influenced by the environment limit the scope of these results. However, combining these results across multiple years should allow trends to become more apparent and enable different management strategies to be tested across various climatic and market conditions. 4000 PD 1 PD 2 LSD0.05 = 410 lb/ac 2008 Seed cotton, lb/ac 3750 3500 3250 3000 40 60 Defoliation % 80 100 Figure 1. Seed cotton yields measured across two planting dates and four defoliation times during the 2008 growing season at the Field Crops Unit of E.V. Smith Research Center in Shorter, AL. 2008 AU CROPS: COTTON RESEARCH REPORT 19 COTTON LINT, AND HVI FIBER PROPERTIES MEASURED ACROSS THREE PLANTING DATES (PD) AND FOUR DEFOLIATION TIMES (DEF) AT THE FIELD CROPS UNIT, EVSRC, 2007 PD1 PD2 PD3 Def-40% Def-60% Def-80% Def-100% PD Def PD x Def 1600 1400 1200 2007 Lint yields, lb/ac 1000 800 600 400 200 0 40 60 Defoliation % 80 100 PD 1 PD 2 PD 3 Lint lb/A 1022 670 987 715 884 988 984 0.0021 0.0386 0.0003 Staple 32nds 35 32 33 33 34 33 34 0.0003 0.8950 0.6206 Length in 1.10 1.01 1.04 1.05 1.05 1.05 1.05 0.0000 0.9903 0.9535 Micronaire 34 39 48 40 41 41 40 0.0000 0.8192 0.2262 Strength kN m/kg 281.8 282.6 310.5 293.7 293.3 290.8 288.7 0.0041 0.7054 0.3761 Uniformity % 80.8 80.7 82.0 81.2 81.6 81.3 80.7 0.0165 0.1116 0.0392 LSD0.05 = 207 lb/ac Figure 2. Cotton lint yields measured across three planting dates and four defoliation times during the 2007 growing season at the Field Crops Unit of E.V. Smith Research Center in Shorter, Alabama. 83.0 82.5 82.0 Uniformity, % 81.5 81.0 80.5 80.0 79.5 79.0 78.5 40 60 Defoliation % Figure 3. Cotton fiber uniformity values measured across three planting dates and four defoliation times during the 2007 growing season at the Field Crops Unit of E.V. Smith Research Center in Shorter, Alabama. LSD0.05 = 1.0 % PD 1 PD 2 PD 3 80 100 20 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF A CORS FOR USE BY ALABAMA PRODUCERS A. Winstead, S. H. Norwood, J. P. Fulton, and T. Harbuck Data provided by a Continuously Operating Reference Station (CORS) can be used for Real-Time Kinematic (RTK) applications in agriculture. The main use for CORS in agriculture has been to replace traditional base station use by producers for RTK level guidance systems. Agriculture equipment outfitted with an internet accessible cellular phone or modem (with internet data package) and RTK-level GPS equipment can utilize the aroundthe-clock data output for their GPS correction signal (Figure 1). A CORS provides extended signal range (with no line-of-sight, only cellular coverage, required), accessibility by a wide range of users, and reduced investment costs for RTK-level technology (i.e. auto-steer systems). Therefore, the objective of this study was to evaluate the accuracy of autoguidance systems utilizing CORS as their correction service. Courtland CORS Project. In March 2008, the Alabama Cooperative Extension System facilitated a partnership between Lawrence County, Alabama, farmers; the Alabama Department of Transportation; the Lawrence County Board of Education; and Alabama commodity groups (Alabama Cotton Commission and Alabama Wheat and Feed Grain Committee) for installation of the first CORS site designated for agriculture (Figure 2). While the site remains accessible to the public, the primary users have been Alabama producers, making it the first of its kind in the nation. Results and Planned Efforts. Preliminary data collected on the Auburn Campus suggest that 2 to 4 inch horizontal accuracy can be maintained up to 25 miles from the base station. However, a more thorough investigation is planned during 2009 with compatible autoguidance systems set up to use CORS. RTK autosteer systems at the Tennessee Valley (Belle Mina, Alabama) and Gulf Coast (Fairhope, Alabama) Research and Extension Center were upgraded in 2008 to make them compatible for use with CORS. Each tractor was upgraded to a Trimble Field Manager Display, RTK GNSS AgGPS 442 Receiver with NavII Controller and 900 MHz radio. Installation of the appropriate modems and data packages is planned for February 2009 with testing to commence shortly thereafter. Research will focus on evaluating the position accuracy, repeatability, and applications of CORS for agriculture during 2009 at both Research and Extension Centers. The dynamic assessment will determine horizontal and vertical position accuracy as a function of distance from the CORS site, accuracy of CORS as compared to a traditional base station, and repeatability of CORS data as compared to RTK base stations. Figure 1. Tractor equipped with RTK GPS receiver and Internet accessible cellular phone, which receives real-time GPS correction signal from a CORS site in Lawrence County, Alabama. Figure 2. CORS GPS receiver mounted on top of a building in Courtland, Alabama (left), and streaming data output from Courtland station (right). 2008 AU CROPS: COTTON RESEARCH REPORT 21 EVALUATION OF VARIABLE-RATE SEEDING FOR COTTON J. P. Fulton, S. H. Norwood, J. N. Shaw, C. H. Burmester, C. Brodbeck, A. Winstead, B. Ortiz, M. H. Hall, and P. L. Mask This ongoing study was conducted through collaboration with a cooperative farmer in Northern Alabama and covers 2006 through 2008. The objective of this project is to evaluate opportunities for increased yield or profits through variable-rate (VR) seeding for cotton production. This farmer utilizes a cotton and corn rotation while also managing center pivot irrigation on a select portion of managed farmland permitting the comparison of irrigated and dryland cotton production. Selected seeding rates, based on the farmer’s traditional seeding rates and recommendations from consultants for both dryland and irrigated fields, included 35,000, 50,000, 65,000, and 80,000 seeds per acre. A 24-row planter equipped with a VR drive system was used. A plot within each field was blocked to provide four replications for each seeding treatment. Treatments were then randomly assigned within each block with a single pass of the planter representing a specific population treatment within the block. Subsequent to planting, stand counts were measured to determine the actual germinated population. Stand count measurements were gathered on each 12-row section of the planter, and counts were collected at three or more places along each of the two sections, depending upon terrain variability. A cotton picker equipped with an AgLeader yield monitor was used to obtain spatial performance data for each plot. Yield and stand count data were statistically analyzed for each year individually, using T-tests and Least Significant Difference (α = 0.1) to determine if differences existed between seeding treatments. Results showed that stand counts were all significantly lower in both irrigated and non-irrigated fields than the targeted seeding rate with the exception of one treatment (35,000 seeds SUMMARIZED YIELD AND EMERGENCE DATA FOR 2006, 2007, AND 20081 Treatment seed/A 35,000 50,000 65,000 80,000 35,000 50,000 65,000 80,000 35,000 50,000 65,000 80,000 1 —Field 1, nonirrigated— Actual Yield plants/A lb sc/A 2008 25,628 d 2,417 a 34,558 c 2,373 a 40,583 b 2,393 a 47,190 a 2,312 a 2007 38,714 b 1,796 a 32,815 b 2,293 a 39,986 b 2,162 a 56,701 a 1,878 a 2006 33,251 d 1,651 c 40,874 c 1,553 c 54,813 b 1,560 c 62,944 a 1,612 c —Field 2, irrigated— Actual Yield plants/A lb sc/A 32,428 b 32,888 b 44,431 a 48,569 a 27,080 b 31,508 a 42,979 a 52,490 a 26,455 d 37,679 c 47,335 b 52,199 a 2,671 a 2,684 a 2,148 a 2,356 a 2,812 b 3,136 ab 3,271 a 3,256 a 3,457 ab 2,733 b 2,928 b 3,979 a per acre within the irrigated plot). A plant population lower than the target application rate has been a consistent result repeated through the 2006, 2007, and 2008 growing seasons. It has been thought that this could be a result of improper planter calibration or late freezes affecting emergence; however, the reason for the lower than expected actual populations is still unknown. Statistically comparing the actual populations of the four seeding rates indicated that as the target seeding rate was increased, there was a significant increase in the actual population for all four seeding rates in the non-irrigated field. For the irrigated results, a similar trend existed; the two higher seeding rates, 65,000 and 80,000, had significantly higher actual populations that the two lower seeding rates, 35,000 and 50,000. A significant difference in seed cotton yield between the four seeding rates did not exist for both irrigated and non-irrigated treatments (see table). This outcome was interesting since both irrigated and non-irrigated plots produced significant differences in the actual plant populations in 2006 and 2008 with no differences in yield. In 2008, there were no yield differences between the irrigated and non-irrigated fields. In summary, similarities were reported for the 2006, 2007, and 2008 growing seasons. On the non-irrigated treatments, the actual populations were all significantly less than the target population during the three growing seasons except for the lowest seeding rate (35,000) in the 2006 and 2007 growing seasons. While significant differences between actual populations did exist for most seeding rates in the non-irrigated treatments (except 35,000, 50,000, and 65,000 in 2007), no significant differences in seed cotton yields were reported for the 2006, 2007, and 2008 growing seasons. In the irrigated treatments, all actual populations were significantly lower than the target seeding rates throughout the three growing seasons, except for the 35,000 treatment in 2008. Reported actual populations and seed cotton yields for the irrigated treatments during the three growing seasons were not as consistent as with the non-irrigated treatments. For example, during the 2006 growing season there were significant differences between actual populations for all seeding rates, in 2007 only the 35,000 population was significantly lower, and in 2008 the 65,000 and 80,000 populations were significantly higher that the two lower target rates. Statistically, the results for the non-irrigated and irrigated cotton were similar for 2006, 2007, and 2008 suggesting that increasing seeding rates has minimal impact on yield. A more thorough analysis is being conducted for this study. Statistical comparisons were only performed within each year and column. Means with similar letters in each column for each year indicates they are not statistically different at the 90 percent confidence level. 22 ALABAMA AGRICULTURAL EXPERIMENT STATION THE OLD ROTATION (CIRCA 1896) - 2008 C. C. Mitchell, D. P. Delaney, and K. S. Balkcom The Old Rotation (circa 1896) is the oldest, continuous cotton experiment in the world. Its 13 plots on 1 acre of land on the campus of Auburn University continue to document the longterm effects of crop rotations with and without winter legumes (crimson clover) as a source of nitrogen for cotton, corn, soybean, and wheat. The 112th year of the Old Rotation experiment continues the trend that began in 1996 when the experiment changed from conventional tillage to conservation tillage and GMO crops. Good yields of most crops were produced in 2008 with irrigation. Non-irrigated cotton and corn suffered through another drought year in Central Alabama. Erratic yields from the winter legume cover crop (A.U. Robin crimson clover) have puzzled project leaders for the last three or four years. We speculate that residue from the cotton defoliant, Dropp® (thidiazuron) and Ginstar® (thidiazuron + diuron), may be affecting germination and survival of the crimson clover planted after cotton harvest. An alternative defoliant was used in the fall of 2008. Plot 1 2 3 4 5 6 7 8 9 10 11 12 13 Description no N/no legume winter legume winter legume cotton-corn cotton-corn + N no N/no legume cotton-corn winter legume cotton-corn + N 3-year rotation 3-year rotation 3-year rotation cont. cotton/ no legume + N Mean Clover dry matter Irrig. Non-irrig. lb/A lb/A 0 0 1214 1747 1074 1754 1464 973 1532 1201 2423 2675 776 1350 658 1939 1404 1405 0 0 2506 2831 0 0 1450 1764 TABLE 1. OLD ROTATION YIELDS, 2008 Wheat Non-irrig. bu/A ——Corn—— Irrig. Non-irrig. bu/A bu/A 49.5 184.2 63.9 159.9 24 0 0 ——Cotton—— Irrig. Non-irrig. lb/lint/A lb lint/A 758 444 845 706 1420 688 1194 714 1446 592 819 514 corn corn 1194 802 corn corn 1481 462 corn corn wht/sbn wht/sbn 1420 531 1175 606 —Soybean— Irrig. Non-irrig. bu/A bu/A 40.2 28.8 131.2 8 TABLE 2. EFFECT OF ROTATION TREATMENT AND IRRIGATION ON COTTON LINT YIELDS, 2003-2008 Treatment No N/no legumes Legume N only 120 lb N/A 2-yr rotation/ legume N only 2-yr rotation + legumes + 120 lb N/A 3-yr rotation/ no N P>F for Treatment P>F for Irrigation ——2003—— ——2004—— ——2005—— ——2006—— ——2007—— ——2008—— Irrig. Non-irrig. Irrig. Non-irrig. Irrig. Non-irrig. Irrig. Non-irrig. Irrig. Non-irrig. Irrig. Non-irrig. ——————————————————lint yield lb/A———————————————————— 320 240 500 400 450 470 520 380 540 0 790 480 1000 1150 1200 990 690 850 1140 1300 1040 710 1150 730 1040 1200 1610 1180 720 1040 1420 1260 1830 0 1420 530 1030 1030 1330 1120 770 1020 1400 1650 1370 920 1990 710 1080 1520 1650 1150 1210 1660 1730 1760 1940 750 1450 530 960 850 ≤ 0.01 0.21 ns 1450 360 ≤ 0.01 ≤ 0.01 1060 850 ≤ 0.01 0.05 900 900 ≤ 0.01 0.60 ns 1660 250 0.06 ≤ 0.01 1480 460 0.11 ≤ 0.01 continued TABLE 2. EFFECT OF ROTATION TREATMENT AND IRRIGATION ON COTTON LINT YIELDS, 2003-2008, CONTINUED Treatment No N/no legumes Legume N only 120 lb N/A 2-yr rotation/ legume N only 2-yr rotation + legumes + 120 lb N/A 3-yr rotation/ no N Overall mean P>F for Treatment = ≤ 0.01 P>F for Irrigation = ≤ 0.01 ——Six-yr. mean 1—— Irrig. Non-irrig. —lint yield lb/A— 520 d 330 d 1040 c 850 d 1340 ab 870 bc 1320 ab 1080 ab 1510 a 1250 a 1250 bc 1060 670 c 820 Means within a column and followed by the same letter are not significantly different at P=0.05. 2008 AU CROPS: COTTON RESEARCH REPORT 23 This is the sixth year that irrigation on the Old Rotation could be compared with non-irrigated plots. Irrigation had a highly significant effect on cotton yields in four of the six years. The last two years, 2007 and 2008, have been drought years and dramatic differences are apparent (Table 2). Corn grain yields are more erratic from year to year even with irrigation (Table 3). However, mean corn grain yields over the past six years indicate a highly significant increase due to irrigation. Likewise, mean soybean yields following wheat are increased with irrigation. TABLE 3. EFFECT OF ROTATION TREATMENT AND IRRIGATION ON SOYBEAN AND CORN GRAIN, 2003-2008 Treatment 3-yr rotation 2-yr rotation/ legume N only 2-yr rotation + legumes + 185 120 lb N/A 3-yr rotation/ no N 75 CORN MEAN 112 Treatment ————2003———— ————2004———— ————2005———— Irrigated Nonirrigated Irrigated Nonirrigated Irrigated Nonirrigated ———————————————————bushels/A——————————————————— SOYBEAN YIELD 43.2 41.3 60.6 59.8 48.3 26.9 CORN YIELD 78 82 62 52 62 34 164 86 110 186 183 143 113 99 88 133 52 82 141 48 74 3-yr rotation 2-yr rotation/ legume N only 2-yr rotation + legumes + 154 120 lb N/A 3-yr rotation/ no N 103 CORN MEAN 106 Treatment ————2006———— ————2007———— ————2008———— Irrigated Non-irrigated Irrigated Non-irrigated Irrigated Non-irrigated ———————————————————bushels/A——————————————————— SOYBEAN YIELD 66.1 48.3 61.5 20.6 40.2 28.8 CORN YIELD 62 54 81 46 50 24 118 74 82 173 183 145 42 50 462 .184 160 130 0 0 82 2-yr rotation/ legume N only 2-yr rotation + legumes + 169 a 120 lb N/A 3-yr rotation/ no N 126 b Overall mean 120 1 2 6-YEAR CORN MEAN1 Irrigated Non-irrig. -——grain yield, bu/A—— 65 c 49 b 96 a 59 b 682 --3-yr rotation 6-YEAR SOYBEAN Mean Irrigated Non-irrig. —————bu/A————— ---53 -39.13 Values followed by the same letter are not significantly different at P≤ 0.05. Non-irrigated mean significantly different from irrigated mean at P≤ 0.05. 3 Non-irrigated mean significantly different from irrigated mean at P≤ 0.001, 24 ALABAMA AGRICULTURAL EXPERIMENT STATION THE CULLARS ROTATION (CIRCA 1911) - 2008 C. C. Mitchell, D. P. Delaney, and K. S. Balkcom The Cullars Rotation is the oldest, continuous soil fertility experiment in the southern United States and the second oldest experiment in the world that includes cotton. It was placed on the National Register of Historical Places in 2003. It continues to document the long-term yield trends of five crops in a threeyear rotation with 14 soil fertility variables. Each fertility treatment is replicated three times. On the Marvyn loamy sand where the Cullars Rotation is located, dry weather, particularly early in the growing season, limited yields of wheat, corn and cotton. Timely fall rainfall helped yields of soybean (see table). All corn and cotton plots received 120 pounds total N per acre in split applications except on plots A, B, and C. The complete fertilizer plus micronutrient treatment produced the equivalent of almost three bales of cot- ton per acre. In spite of the dry fall, soybean yields were generally higher than the irrigated soybean yields on the nearby Old Rotation experiment. The 2005 yields continue a trend of high yields that began about the time we converted this experiment from conventional tillage to conservation tillage in 1997. Conservation tillage includes either in-row subsoiling or paratilling prior to planting wheat, cotton, and corn. While long-term trends seem to indicate higher yields on the well-fertilized plots, the plots with low levels of one or more nutrient or factor (e.g., plot C [nothing], plot 2 [no P], plot 6 [no K], and plot 8 [no lime]), continue a trend toward lower yields. For example, plot C (nothing) produced very low yields of most crops until recently when we get nothing from this treatment. Yields on the no P, no K, and no lime plots are also decreasing. Plot A B C 1 2 3 4 5 6 7 8 9 10 11 Description no N/+legume no N/no legume nothing no legume no P complete 4/3 K rock P no K 2/3 K no lime no S complete + micros 1/3 K Clover dry matter lb/A 1320 0 0 0 282 2090 1321 1221 0 1038 0 425 1545 1164 CULLARS ROTATION YIELDS, 2008 Wheat bu/A 19.1 18.3 0.0 38.7 19.1 45.6 41.0 38.2 26.6 45.9 15.4 50.2 49.1 48.1 Corn Non-irrig. bu/A 35.8 42.3 0.0 39.8 0.0 39.8 45.4 41.4 0.0 42.6 13.4 39.5 50.7 33.0 Cotton Non-irrig. lb lint/A 767 906 0 984 993 932 906 1106 0 950 427 854 845 802 Soybean Non-irrig. bu/A 43.1 41.3 0.0 40.9 10.9 41.8 43.9 45.2 22.8 42.4 15.5 42.7 41.0 41.7 2008 AU CROPS: COTTON RESEARCH REPORT 25 IMPACT OF CROP ROTATION ON DISEASES AND NEMATODE PESTS OF COTTON, CORN, AND PEANUT AS WELL AS ON THE ECONOMICS OF COTTON, CORN, AND PEANUT PRODUCTION A. K. Hagan, K. L. Bowen, K. S. Lawrence, H. L. Campbell, C. D. Monks, D. P. Delaney, and R. W. Goodman Studies concerning the impact of rotation on disease and nematode pests of cotton, corn, and peanut are in progress at the Plant Breeding Unit of the E.V. Smith Research Center, the Gulf Coast Research and Extension Center, and the Wiregrass Research and Extension Center. Corn is an excellent bridge host for the cotton root knot nematode between cotton crops. Reproduction rates for this nematode on corn and cotton are similar. Reduced cotton yields are linked with increasing cotton root knot larvae populations that are associated with continuous cotton or cotton – corn rotation patterns. Regardless of the cropping sequence, no intensi- fication of any diseases of cotton or corn has been observed at any study location. Higher yields were noted when cotton was cropped behind at least one year of peanut. Due to nematode suppression and yield gains, peanut is a better rotation partner for cotton than corn in fields where the cotton root knot nematode is present. Corn and cotton are not bridge hosts for peanut root knot nematode, and pod yields are higher where peanut follows one or more years of corn or cotton due reduced disease pressure. Results are provided here for the Plant Breeding Unit (PBU) and the Gulf Coast Resarch and Extension Center (CGREC). TABLE 1. IMPACT OF COUNTER INSECTICIDE/NEMATICIDE TREATMENT ON COTTON ROOT KNOT JUVENILE COUNTS AND YIELD OF CORN WHEN AVERAGED ACROSS ALL CROPPING SEQUENCES, PBU, 2008 Treatment and rate/A Counter 15G 6.5 lb Non-treated control Cotton root knot counts1 341 a 366 a Yield bu/A 126 a 120 a TABLE 2. IMPACT OF CROP SEQUENCE ON COTTON ROOT KNOT NEMATODE COUNTS AND ON THE YIELD OF CORN, PBU, 2008 2003 Corn Corn Pnut Pnut Cttn Cttn Cttn Cttn 1 1 Number of J2 cotton root knot (Meloidogyne incognita race 3) juveniles per 100cm3 soil sample. Means in each column that are followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). 2004 Corn Corn Corn Pnut Corn Corn Corn Cttn 2005 Corn Corn Pnut Corn Cttn Corn Corn Corn 2006 2007 Corn Corn Pnut Corn Corn Pnut Pnut Pnut Corn Cttn Cttn Corn Corn Cttn Cttn Cttn 2008 Corn Corn Corn Corn Corn Corn Corn Corn Cotton root knot counts1 298 bcd 330 abc 74 d 159 cd 516 ab 362 abc 528 ab 561 a Yield bu/A 106 e 128 bc 141 ab 151 a 113 de 121 cd 109 de 113 de Number of J2 cotton root knot (Meloidogyne incognita race 3) juveniles per 100cm3 soil sample. Means in each column that are followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). TABLE 3. IMPACT OF CROP ROTATION ON THE LEVEL OF DAMAGE ATTRIBUTED TO DISEASES AND NEMATODES OF PEANUT, PBU, 2008 2003 Corn Corn Pnut Cttn Cttn 1 2 2004 Pnut Corn Pnut Pnut Cttn 2005 Corn Pnut Pnut Cttn Pnut 2006 Pnut Corn Pnut Pnut Cttn 2007 Corn Corn Pnut Cttn Cttn 2008 Pnut Pnut Pnut Pnut Pnut TSWV1 5.0 a 3.3 a 3.0 a 2.0 a 2.5 a ELS2 5.1 ab 5.0 ab 5.8 a 5.5 ab 4.6 b White mold1 10.5 b 9.0 b 22.0 a 6.0 b 6.0 b Yield bu/A 3967 b 4118 b 2399 c 4967 ab 5002 a TSWV and average white mold incidence is expressed as number of hits per 60 foot of row. Early leaf spot (ELS) was rated using the Florida 1 to 10 scoring system. Means in each column followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). —————————————————Crop Sequence————————————————— 2003 2004 2005 2006 2007 2008 Cotton Cotton Cotton Cotton Cotton Cotton Peanut Peanut Cotton Peanut Peanut Cotton Peanut Cotton Peanut Cotton Peanut Cotton Peanut Cotton Cotton Peanut Cotton Cotton Cotton Cotton Cotton Peanut Cotton Cotton Cotton Cotton Cotton Corn Cotton Cotton TABLE 4. IMPACT OF CROP SEQUENCE ON COTTON YIELD, PBU, 2008 Seed cotton lb/A 2375 b 3178 a 3003 a 2376 b 2450 b 2185 b Means in each column followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). 26 ALABAMA AGRICULTURAL EXPERIMENT STATION TABLE 5. AVERAGE YIELD RESPONSE OF CORN ACROSS ALL CROPPING SEQUENCES TO COUNTER 15G INSECTICIDE/ NEMATICIDE, GCREC, 2008 Treatment and rate/A Counter 15G 6.5 lb Non-treated control Yield bu/A 107.6 a 108.6 a TABLE 6. IMPACT OF CROP SEQUENCE ON THE YIELD OF CORN AND ROOT KNOT NEMATODE JUVENILE COUNTS, GCREC, 2008 2003 Corn Corn Pnut Pnut Cttn Cttn Cttn Cttn 2004 Corn Corn Corn Pnut Corn Corn Corn Cttn 2005 Corn Corn Pnut Corn Cttn Corn Corn Corn 2006 Corn Pnut Corn Pnut Corn Cttn Corn Cttn 2007 Corn Corn Pnut Pnut Cttn Corn Cttn Cttn 2008 Corn Corn Corn Corn Corn Corn Corn Corn Yield bu/A 104 d 109 c 116 a 111 ab 106 bcd 100 d 109 bc 111 ab Means in each column that are followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). Means in each column that are followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). TABLE 7. IMPACT OF CROP ROTATION ON THE LEVEL OF DAMAGE ATTRIBUTED TO DISEASES AND NEMATODES IN PEANUT, GCREC, 2008 2003 Pnut Corn Corn Cttn Cttn 1 2 2004 Pnut Pnut Corn Pnut Cttn 2005 Pnut Corn Pnut Cttn Pnut 2006 Pnut Pnut Corn Pnut Cttn 2007 Pnut Corn Corn Cttn Cttn 2008 Pnut Pnut Pnut Pnut Pnut TSWV1 3.8 a 3.3 a 3.0 a 4.3 a 2.3 a ELS2 4.5 a 3.4 b 3.0 b 3.0 b 2.8 b White mold1 3.1 a 1.0 b 1.8 ab 1.4 b 1.5 ab Yield bu/A 4238 b 4953 a 4969 a 4311 b 4793 a TSWV and average white mold incidence is expressed as number of hits per 60 foot of row. Early leaf spot (ELS) was rated using the Florida 1 to 10 scoring system. Means in each column followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). TABLE 8. IMPACT OF MONCUT 70DF ON PEANUT YIELD AND WHITE MOLD INCIDENCE AVERAGED ACROSS ALL PEANUT CROPPING SEQUENCES, GCREC, 2008 Treatment and rate/A Moncut 70DF Non-treated Control 1 White mold1 0.6 b 3.0 a Yield bu/A 4659 a 4652 a White mold incidence is expressed as number of hits per 60 foot of row. Means in each column that are followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). ———————————————Crop Sequence——————————————— 2003 2004 2005 2006 2007 2008 Cotton Cotton Cotton Cotton Cotton Cotton Peanut Peanut Cotton Peanut Peanut Cotton Peanut Cotton Peanut Cotton Peanut Cotton Peanut Cotton Cotton Peanut Cotton Cotton Cotton Cotton Cotton Peanut Cotton Cotton Cotton Cotton Cotton Corn Cotton Cotton TABLE 9. IMPACT OF CROPPING SEQUENCE ON COTTON YIELD, GCREC, 2008 Seed cotton lb/A 2643 a 2394 a 2439 a 2609 b 2439 b 2507 b Means in each column followed by the same letter are not significantly different according to Fisher’s least significant difference (LSD) test (P=0.05). IRRIGATION SPRINKLER IRRIGATION FOR SITE-SPECIFIC, PRECISION MANAGEMENT OF COTTON M. P. Dougherty, A. Abdelgadir, J. P. Fulton, C. H. Burmester, B. E. Norris, D. H. Harkins, L. M. Curtis, and C. D. Monks A sprinkler irrigation scheduling study initiated in 2006 at the Tennessee Valley Research and Extension Center (TVREC) was continued in 2008. The study evaluates cotton yield response to six irrigation treatments ranging from 0 percent (rainfed) to 125 percent of calculated pan evaporation adjusted for percent canopy cover. In 2007, the study was conducted on 48 plots, 39 feet long and 39 feet wide, arranged in a randomized complete block design with four replications. In 2008, a canolasoybean-cotton rotation was incorporated into 24 of the 48 sprinkler test plots to assess the economic feasibility of adding two oil crops to a northern Alabama cotton rotation. Total seasonal rainfall (June to August) at TVREC for 2008 was 11.27 inches, which was near the normal average of 11.50 inches. Comparable growing season rainfall in 2006 and 2007 was less than 6.5 inches (Figure 1). Because of higher rainfall in 2008, rainfed, non-irrigated yields were higher in 2008 than in 2006 and 2007 (Figure 2). 14.00 Due to irrigation malfunction, both the 50 percent and 75 percent irrigation treatments in 2008 were discarded. Due to the same malfunction, very little irrigation water (less than 0.5 inch) was applied to the 100 percent irrigation treatment during August and September. However, yield was not negatively impacted and treatment results are included in Table 1. All three 2008 irrigation treatments reported in Table 1 significantly increased (α = 0.10) seed cotton yield over the rainfed (0 percent) control. Irrigation near 100 percent of calculated pan evaporation adjusted for percent canopy cover resulted in the best yield in all three seasons (Table 1). Average sprinkler irrigated cotton yields were 2.3, 3.5, and 3.1 bales per acre in 2006, 2007, and 2008, respectively, compared to the three-season average of 1.5 bales per acre for rainfed controls. Malfunction of the 2008 irrigation scheduling system has been corrected for the upcoming 2009 season. 5000 4500 Seed cotton yield (lb/ac) 12.00 Rainfall (inch) 10.00 8.00 6.00 4.00 2.00 0.00 2006 2007 6.63 11.27 11.50 4000 3500 3000 2500 2000 1500 1000 500 0 0 5 10 15 20 25 30 6.06 2006 2007 2008 Irrigation water (inch) 2008 79-YR Mean Figure 1. Total seasonal rainfall during the June, July, and August periods versus the 79-year average. Figure 2. Effect of total amount of irrigation water on seed cotton yield at TVREC during 2006-2008. (Note: In 2008 two irrigation treatments were discarded due to irrigation malfunction.) Irrigation Treatment TABLE 1. IRRIGATION AMOUNTS AND LINT YIELD FOR SPRINKLER-SCHEDULING TRIALS, 2006-081 ——2006—— Irrig. Bales/A in 0.00 1.2 4.87 1.7 10.1 2.0 15.2 2.2 2.8 2.9 0 25 percent 50 percent 75 percent ——2007—— ——2008—— Irrig. Bales/A Irrig. Bales/A in in 0.00 1.0 0.00 2.3 4.29 2.2 3.16 3.0 9.63 3.4 3.702 — (6.76) 14.7 3.8 5.862 — (10.3) 19.3 24.4 4.0 3.9 7.91 (13.9) 17.3 3.3 3.1 100 percent 20.4 125 percent 25.2 1 In 2006, N=4, turnout = 38 percent. In 2007, N=8, turnout = 41 percent. In 2008, N=4, turnout 40 percent. 2 In 2008, the irrigation treatments 50 percent and 75 percent were discarded due to irrigation malfunction. Numbers in parentheses indicate target irrigation that was not achieved due to malfunction. 28 ALABAMA AGRICULTURAL EXPERIMENT STATION SUBSURFACE DRIP IRRIGATION FERTIGATION FOR SITE-SPECIFIC, PRECISION MANAGEMENT OF COTTON M. P. Dougherty, A. Abdelgadir, J. P. Fulton, C. H. Burmester, B. E. Norris, D. H. Harkins, L. M. Curtis, and C. D. Monks A subsurface drip irrigation study was installed at the Tennessee Valley Research and Extension Center (TVREC) in 2005 to evaluate four precision fertigation management scenarios. Approximately 7,500 feet of subsurface drip irrigation tape and four positive displacement liquid fertilizer injectors were installed on five treatments with four replications in randomized complete block design. The twenty treatment plots were made up of eight, 345-foot rows of cotton on a 40-inch row spacing, with drip tape between every other row of cotton. The four fertigation treatments and one non-fertigated control are described in Table 1. Yield results for 2008, are shown in Figure 1. Total seasonal rainfall at TVREC from June to August 2008 was 11.27 inches, which was near the normal average of 11.50 inches. Thus, seed cotton yields for this season were higher than in 2006 and 2007. The response to fertilizer treatments in 2008 was similar to 2007. In 2008, the 100 percent fertigated treatments (three and four) produced significantly lower (α= 0.1) yields than treatment one (100 percent surface-applied) and treatment five (30 percent surface + 70 percent drip), and they gave comparatively lower yield than treatment two (15 percent surface + 85 percent drip). The non-fertigated control treatment and the fertigated treatments that received surface-applied, preplant nitrogen and potassium (K2O) responded much better in 2008, possibly due to sufficient rainfall and better downward movement of surfaceapplied fertilizer. However, higher rains may have also resulted in leaching fertigated nutrients farther out of the root zone. This may explain observed plant yellowing and reduced vegetative growth in treatments 3 and 4 during the season, although soil compaction impeding root growth to fertigated nutrients cannot be ruled out. Treatments one and five were statistically the best yielding treatment in 2008 whereas treatments three and four were the lowest yielding. Cotton yield (bales per acre), lint quality parameters, and leaf nutrient analyses are presented in Table 2. None of the quality parameters were significantly affected by different fertilizer treatments except for lint length. Lint length in the 100 percent fertigated treatments (4) was significantly higher (α=0.1) than the fertigated treatments that received surface-applied, preplant nitrogen (N) and potassium (K2O). Plant uptake for N and K was significantly higher (α=0.1) in the surface-applied control treatment (treatment 1) than all fertigated treatments, with or without surface application. Higher seasonal rainfall in 2008 may have assisted delivery of surfaceapplied, preplant N and K. Phosphorus, Ca, and Mg contents were not significantly affected by any treatment. Treatment1 1. Control - drip irrigated, with all fertilizers surface applied 2. Timing 1 – with surface preplant fertilizer 3. Drip timing 1 – no preplant fertilizer 4. Drip timing 2 – no preplant fertilizer “spoon-fed” 5. Timing 2 – with surface preplant fertilizer TABLE 1. TREATMENT DESCRIPTION, FERTIGATION MANAGEMENT TRIALS, 2008 Description Preplant N and K at 60 pounds per acre Post-Plant N (75 pounds per acre) sidedressed at early square Preplant 20 pounds of N and K (surface) Drip 40 pounds N,K – square to bloom (25 days) Drip 75 pounds N,K – bloom to 25 days Planting Drip 20 pounds N,K Drip 40 pounds N,K – square to bloom (25 days) Drip 75 pounds N,K – bloom to 25 days Planting Drip 20 pounds N,K Drip 40 pounds N,K – square to bloom (25 days) Drip 75 pounds N,K – bloom to 40 days Preplant 40 pounds of N and K (surface) Drip 95 pounds N,K – square through bloom (50 days) 1 All treatments received 135 pounds per acre of nitrogen and potassium (K2O), 20 pounds per acre of sulfur, and l.0 pound per acre of boron. Phosphorus fertilizer was surface-applied to maintain P at high soil test levels. Drip fertilizer was 8-0-8-1.2S-0.06B made using 32 percent liquid N, potassium thiosulfate, fertilizer grade KCL, Solubor, and water. TABLE 2. LINT YIELD AND QUALITY ANALYSIS, COTTON FERTIGATION MANAGEMENT TRIALS, 2008 Treatment1 1 2 3 4 5 1 Yield bales/A 3.9 a 3.5 b 3.4 b 3.3 b 3.8 a Mic 4.62 a 4.78 a 4.75 a 4.58 a 4.65 a Length 1.10 b 1.07 c 1.11 ab 1.13 a 1.09 bc Strength Uniformity 27.2 a 84.2 a 27.2 a 83.2 a 28.5 a 84.1 a 28.4 a 84.5 a 28.9 a 84.0 a N % 4.32 a 3.36 c 3.24 c 3.35 c 3.57 b P % 0.28 a 0.27 a 0.28 a 0.30 a 0.28 a K % 1.20 a 1.09 b 1.13 b 1.14 b 1.13 b Ca % 2.27 a 2.22 a 2.26 a 2.36 a 2.28 a Mg % 0.26 a 0.26 a 0.25 a 0.26 a 0.26 a Treatment 1. Surface applied N-P-K with drip irrigation (control). Treatment 2. Preplant 20 pounds N-K surface with two N-K drip timings. Treatment 3. 20 lb N-K drip at planting with two N-K drip timings (to 25 days after bloom). Treatment 4. 20 lb N-K at planting with two N-K drip timings (to 40 days after bloom). Treatment 5. Preplant 40 pounds N-K surface with one N-K drip timing (square through bloom). Different subscripts denote statistical difference (α=0.1). N=4. Turnout = 40 percent. 2008 AU CROPS: COTTON RESEARCH REPORT 29 EVALUATING PRESSURE COMPENSATING SUBSURFACE DRIP IRRIGATION FOR NO-TILL ROW CROP PRODUCTION ON ROLLING, IRREGULAR TERRAIN J. P. Fulton, M. P. Dougherty, J. N. Shaw, R. L. Raper, L. M. Curtis, C. Brodbeck, C. H. Burmester, B. Durham, D. H. Harkins, A. Winstead, and S. H. Norwood This investigation was conducted on a 12-acre field located at the Tennessee Valley Research and Extension Center (TVREC), Belle Mina, Alabama. The two major objectives were to evaluate cotton production on rolling terrain irrigated with subsurface drip irrigation (SDI) in conjunction with cover crops and to evaluate spatial yield variability as related to water distribution and topography. The experimental design was a randomized block design with two irrigation treatments (irrigated and non-irrigated) and two cover crop treatments (cover and no cover) with four replications (Table 1). Each of the four treatments was replicated four times. Plots measured 27 feet by 1250 feet with SDI tape on 80-inch spacing (every other row of 40-inch cotton) and buried at an average depth of 13 inches. Plots receiving a cover crop treatment were planted with rye at a rate of 90 pounds per acre on November 2, 2007. The cover crop was desiccated on March 25, 2008. Cotton, variety ST 4554 B2RF, was planted on April 21, 2008. Yield and quality data were analyzed to determine significant differences (α=0.10). In 2008, irrigated treatments were scheduled based on daily application of 90 percent of daily pan evaporation, adjusted for percent crop canopy cover. However, with the dry early growing season, the daily amount was increased to maintain sufficient soil moisture within the rooting zone. Similarly, in 2007 the 90 percent pan adjusted for crop canopy was used but modified in mid-June to increase the application to more than two times the 90 percent level due to obvious plant development problems caused by extremely low soil moisture. Insufficient soil moisture monitoring in 2007 made it difficult to identify crop water deficiencies in advance of visible plant stress in early June. Soil moisture monitoring was initiated in 2008; however, due to delays with moisture profiler tube installation, monitoring did not commence until May 2. While there were some differences in soil moisture between the treatments, discrepancies existed making it difficult to evaluate the adequacy of irrigation scheduling. However, soil moisture sensing did provide feedback to ensure subsoil moisture content was maintained in order to minimize vertical water loss. Significant yield differences were measured between the irrigated and non-irrigated treatments as well as between the cover and no-cover treatments (Table 1). As in 2007, irrigated yields were significantly higher than non-irrigated yields with 2008 irrigated treatments yielding as high as 54 percent more than non-irrigated yields. Irrigated treatment yields averaged approximately 3.3 bales per acre in 2008. A noteworthy difference between 2007 and 2008 yields is the significant difference between the cover and no-cover treatments for both irrigated and non-irrigated. The plots with the cover crops yielded 22 percent and 9 percent higher than the plots without cover crops for the non-irrigated and irrigated treatments, respectively. In 2007 significant differences were not found between cover crop treatments. A quality analysis was conducted by harvesting 50 cotton bolls collected at six locations within each plot in 2007. Quality factors considered were micronaire, strength, uniformity, and lint length (Table 2). There were significant differences between the irrigated and non-irrigated treatments for all quality factors, which also existed in the 2007 quality data (Table 3). In 2008 micronaire values for the non-irrigated plots ranged between 5.1 and 5.4 (Table 2), signifying a gin discount. Uniformity and lint length were significantly higher on irrigated plots, with uniformity classifying as high on the irrigated plots and intermediate on the non-irrigated plots. No significant differences existed between the irrigated plots with a cover crop compared to irrigated plots without a cover crop. Micronaire, strength, uniformity, and lint length were significantly different for the cover and no-cover, non-irrigated treatments. Strength for the non-irrigated, nocover treatment was significantly higher than strength for any of the other treatments. In summary, irrigated treatments in the 2008 growing season had significantly higher yields (46 to 54 percent greater) than non-irrigated treatments comparable to similar yield differences (66 percent) observed in 2007. The winter cover crop plots also had significantly higher yields (9 to 22 percent) over the plots without a cover crop. Results of the 2008 quality data indicated that micronaire, lint uniformity, and lint length were significantly higher on irrigated than non-irrigated plots, a result also observed in 2007. 30 ALABAMA AGRICULTURAL EXPERIMENT STATION TABLE 1. YIELD AVERAGES PER TREATMENT, 2007 AND 2008 Treatment Irrigated / Cover Irrigated / No Cover Non-Irrigated / Cover Non-Irrigated / No Cover ——2007—— Seed Lint cotton bales lb/A bales/A 3574.8 a 3.1 3350.0 b 2.9 1187.9 b 1.0 1119.3 b 1.0 Treatment TABLE 2. QUALITY AVERAGES PER TREATMENT, 2008 Mic.1 ——2008—— Seed Lint cotton bales lb/A bales/A 4476.4 a 3.5 4067.4 b 3.2 2410.4 c 2.0 1866.1 d 1.5 Irrigated / Cover Irrigated / No Cover Non-Irrigated / Cover Non-Irrigated / No Cover 1 Strength Uniformity Length g/Tex % in 4.5 a 28.3 a 83.4 a 1.1 a 4.7 a 28.2 a 83.6 a 1.1 a 5.1 b 29.9 b 82.7 b 1.1 b 5.4 c 27.8 a 82.0 c 1.0 c Values between 3.5 and 4.9 are not discounted at the gin. Mean yields with similar letters indicate they are not statistically different at the 90 percent confidence level. Mean yields with similar letters indicate they are not statistically different at the 90 percent confidence level. Treatment TABLE 3. QUALITY AVERAGES PER TREATMENT, 2007 Mic.1 Irrigated / Cover Irrigated / No Cover Non-Irrigated / Cover Non-Irrigated / No Cover 1 Strength Uniformity Length g/Tex % in 4.7 a 30.0 a 82.9 a 1.10 a 4.6 a 29.4 a 83.0 a 1.11 a 3.3 b 26.3 b 79.6 b 1.05 b 3.1 c 26.1 b 80.9 c 1.08 c Values between 3.5 and 4.9 are not discounted at the gin. Mean yields with similar letters indicate they are not statistically different at the 90 percent confidence level. FERTILITY COTTON SOIL FERTILITY ON ALABAMA BLACK BELT SOILS C. C. Mitchell, G. Huluka, R. P. Yates, and J. Holliman Soil fertility research with cotton has not been conducted on the fine-textured, often calcareous soils of the Alabama Black Belt Prairie region in several decades although as much as 30,000 acres of cotton are being planted on these soils. Most fine-textured, Black Belt soils test low in P and high or very high in K if recognized analytical techniques are used that are appropriate for these highly buffered, often calcareous soils. Nevertheless, cotton growers in this area sometime suspect K deficiency in spite of following the soil test recommendation. Very little research has been conducted to verify soil test calibration or recommendations for cotton on these soils. The purpose of this experiment was to identify optimum rates of N, P2O5, and K2O for cotton on Black Belt soils. Another objective not covered in this paper was to develop soil test calibration for P and K for cotton on this soil. This experiment was laid out in 2004 and was designed to complement the “Rates of NPK Experiment” (circa 1929) on other outlying units of the Alabama Agricultural Experiment Station. The site is on an acid, Vaiden clay (very fine, smetitic, thermic, Vertic Hapludalfs) at the Black Belt Research and Extension Center in Marion Junction, Alabama. Initial soil tests from the site indicated a very uniform site typical of unfertilized Black Belt area cropland (Table 1). Phosphorus was rated low using the Mississippi/Lancaster extract. Potassium was rated very high. The experiment consisted of six N rates, four P rates, five K rates and a no-lime treatment and an unfertilized treatment replicated four times in a randomized block design (Table 2). Plots were 15 × 25 feet with five 36-inch wide rows. Because of disappointing yields in 2005 when cotton was planted no-till into a rye cover crop and excessive rainfall, the decision was made to switch to a ridge tillage system with no cover crop for 2006 and beyond. All the P and K and half of total N were applied within one week of planting in late April. Complement of N was applied in mid-June. Lint yields were estimated by hand-picking 20 feet from the two middle rows in each plot. Relative yields are yields compared to the mean yield of treatment 5, the control treatment, which received 90-100-100 pounds N-P2O5-K2O per acre each year. The 2008 growing season started out as the third drought year in a row for this area. Late summer rains resulted in relatively good cotton lint yields. Early defoliation due to leaf spot was noted in August, especially on the low K treatments (Figure 1). Excessive rainfall and anaerobic soil conditions dramatically limited cotton lint yields in 2005. Drought severely limited yields in 2006, but critical rainfall in July resulted in somewhat higher yields in 2007 (Table 2). Yields were from hand-picked plots. If the 2006 and 2007 crops had been machine harvested, very little of the lint would have been saved because of hard locks and weak bolls. Lint Quality. Cotton lint quality was measured in 2006, 2007, and 2008 on selected treatments by USDA AMS Cotton Program Birmingham Classing Office. There were no differences in mean fiber quality due to soil fertility treatment in 2006 and 2007, but there were differences in 2008 (Table 3). N rates. Because of the higher yields and significant differences in treatment on yields in 2007 and 2008, these data are probably more relevant to producers (Table 2). Optimum total N rates in the two dry years, 2006 and 2007, appear to be around 60 pounds N per acre, although rates above 30 pounds N per acre produced relative yields above 95 percent of maximum. In 2008, optimum yields were closer to the currently recommended 90 pounds total N per acre. There was a more dramatic response to N rates in 2005 but yields were low due to excessive rainfall and denitrification losses on these poorly drained soils. On-farm tests in 2003 when excessive rainfall also limited yields, showed that delaying N application until sidedressing could almost double the yield potential of cotton. In these tests, optimum N rate was 120 pounds N per acre as a sidedress. P2O5 rates. One would have anticipated more dramatic responses to rates of P than we found in these tests because of the low soil test P rating. Except for the low-yielding, wet year of 2005, there was very little yield response to added P. This calls into question the current low rating for this soil test value for cotton. The definition of a low soil test rating indicates that the soil will produce less than 75 percent of its potential without fertilization of that nutrient. Without P in 2006, 2007, and 2008, relative cotton lint yields were above 80 percent. K2O rates. In spite of the fact that this soil initially tested very high in K, there were significant increases in yield with higher rates of K2O up to 100 pounds per acre in 2005, 2007, and 2008. These results provide credibility to grower’s claims that additional K seems to increase yields even though the soils are rated very high for K. There may be justification to change soil test K ratings for these soils and increase K recommendations for cotton. In fact, without added K in 2005, 2007, and 2008, relative yields were at or below 50 percent of highest yields with K fertilization. According to 1994 research, a soil test rating of very low for a nutrient would be associated with a soil capable of producing only 50 percent of optimum yields without additional fertilization of that nutrient. This soil should be rated very low in K instead of very high. At this rating, current recommendations for cotton would be up to 120 pounds K2O per acre. Leaf spot diseases. In early August of 2008, foliar leaf spot diseases (Cercospora /Alternaria complex) were apparent in the low K plots and by mid-August, many of these plots had defoli- 32 ALABAMA AGRICULTURAL EXPERIMENT STATION ated due to the diseases. While this is the first time these diseases have been found in the four years of this experiment, it did appear to be much more severe in the low K treatments. In summary, this site has been plagued with extreme weather conditions and poor cotton yields in two out of four years. However, these conditions are not unlike that faced by most producers on these soils. Significant differences in 2007 and 2008 with reasonable, non-irrigated cotton lint yields suggest a need for modification of soil test ratings for both P and K on these soils. Phosphorus may be currently rated too low and potassium may be rated too high for cotton on these soils. Currently recommended total N rates for cotton on these soils, 90 pounds N per acre, is certainly not too high. Since these are the only established soil fertility variable plots on the Black Belt Research and Extension Center, we hope that they will be maintained indefinitely as is the “Rates of NPK” experiment at six other Alabama locations to provide more conclusive evidence for changes in soil test calibration for similar Alabama soils. Extract used Mehlich-1 Miss/Lancaster 1 TABLE 1. INITIAL, MEAN PLOW-LAYER SOIL TEST VALUE (N=4) FROM SITE TAKEN IN 2004 Soil pH 6.0 6.0 P K Mg Ca —————————————mg/kg and rating1—————————————— 4 Very Low 88 High 35 High 2330 (not rated) 16 Low 180 V. High 60 High 10,000+ Adams et al., 1994 Treatment number 1 2 3 5 4 6 7 8 9 10 5 11 12 13 14 15 5 TABLE 2. FERTILIZER TREATMENTS AND COTTON LINT YIELDS ON A VAIDEN CLAY IN WEST ALABAMA, 2005-2008 Description 16 17 L.S.D P≤ 0.1 1 ——Rate of nutrients applied—— ——————Cotton lint yields—————— N P2O5 K2O 2005 2006 20071 20081 ————————————————————lb/A———————————————————— N rates No N 0 100 100 177 311 870 bcd 960 cde Low N 30 100 100 214 380 1040 ab 1070 bcd Intermediate N 60 100 100 265 403 990 abc 1220 abc Control 90 100 100 388 393 1076 abc 1350 ab High N 120 100 100 237 400 1037 ab 1340 ab No S/VH N 150 100 100 320 387 1040 ab 1360 ab P rates No P 90 0 100 280 378 910 abcd 1300 ab Very low P 90 20 100 205 394 940 abcd 1350 ab Low soil P 90 40 100 274 375 1091 a 1260 abc Intermediate P 90 60 100 233 388 1027 ab 1460 a Control 90 100 100 388 393 1076 abc 1340 ab K rates No K 90 100 0 157 353 585 f 600 f Very low K 90 100 20 170 324 784 de 770 edf Low K 90 100 40 253 295 803 cde 1030 bcd Intermediate K 90 100 60 341 335 922 abcd 1030 bcd High K 90 100 80 319 349 806 cde 1150 abc Control 90 100 100 388 393 1076 ab 1340 ab Other treatments No lime 90 100 100 196 413 1027 ab 1350 ab Nothing 0 0 0 160 300 649 ef 670 ef 135 ns — — Values followed by the same letter are not significantly different at P≤ 0.05. Treatment no. and description Mean of all Mean of all 1. No N 4. 120 lb N/A 7. No P 11. No K 15. 80 lb K2O/A 1 TABLE 3. FIBER QUALITY FROM SELECTED TREATMENTS Lint (%) 47 43 49 a 46 bc 47 b 45 c 46 bc Micronaire 2006 4.60 2007 3.97 20081 4.05 a 4.22 a 4.18 a 3.15 b 3.78 ab Length 97.0 1.02 1.04 a 1.07 a 1.04 a 1.06 a 1.04 a Strength 26.9 26.4 27.5 ab 28.8 a 27.8 ab 26.7 b 28.8 a Uniformity 81.9 81.9 81.9 ab 83.0 a 81.0 b 80.5 b 82.0 ab Values within the same column followed by the same letter are not significantly different at P < 0.05. 2008 AU CROPS: COTTON RESEARCH REPORT 33 Figure 1 (left). Cotton in a “no K” treatment that was completely defoliated by September 1 due to leaf spot disease first noticed on August 1 (right). 34 ALABAMA AGRICULTURAL EXPERIMENT STATION ALTERNATIVE NITROGEN SOURCES FOR COTTON C.C. Mitchell, K. S. Balkcom, and C. H. Burmester Several alternative nitrogen (N) sources, rates of N, and amendments were evaluated at Prattville, Alabama, on cotton in 2008. Nitrogen rates reported in Figure 1 are for sidedress application only. Dry urea produced the highest yield, averaging 1100 pounds lint per acre (Figure 1). Ammonia volatilization was measured from selected topdress N materials for two weeks after they were applied on July 8, 2008. A commercially available, controlled-release N material, Nitamin Nfusion®, was included in the study. This material is recommended to be applied with liquid N or some other readily available N source, but we used it as a Cotton Lint Yields, 2008 ab topdress N application. All plots except the no-N plots received 40 pounds N at planting. Loss of urea from volatilization was also very low for dry urea, less than 5 pounds N per acre out of 80 pounds applied over a two-week period (Figure 2). Ammonia loss from liquid UAN solutions was the highest (20 pounds N per acre out of 80 applied). Dry urea likely dropped below the rolled rye cover crop residue whereas broadcast UAN solution was sprayed on top of the rye residue. Agrotain® (AG) appeared to reduce volatilization losses from urea but not from the UAN solution, but the results were erratic. Estimated net N volatilized over a 2 week period after topdressing Cotton on July 8, 2008. Total N Volatilized (lb/acre 25 20 15 10 5 0 AN Urea Urea+Ag UAN UAN+Ca UAN+Ag Material 1200 1100 1000 900 800 700 600 500 400 300 200 Lint yield (kg/ha)_ <40 lb. N/a> c c c d d <--------------80 lb. N/a-----------------> a ab ab ab ab b c 120 lb. N/a U AN U AN +C N a IT AM IN ® U re U a re a+ A g® Figure 1. Effect of sources of topdress N on cotton lint yields at Prattville in 2008. U AN U AN +C U AN a +A g® N IT AM Am IN ® .N itr at Am e .N itr at e N on e C aC l2 Figure 2. Estimated net N loss from ammonia volatilization over a two-week period following topdressing of cotton on July 8, 2008. INSECT MANAGEMENT EFFECTIVENESS OF DIFFERENT INSECTICIDES IN CONTROLLING SPIDER MITES AND APHIDS INFESTING COTTON T. Reed A strip trial to assess the efficacy of acaricides in suppressing spider mites was conducted at Greenbrier, Alabama, near the Limestone and Madison county line. Acaricides were applied on June 19, 2008 between 7 p.m. and 8:15 p.m. with a CO2 backpack sprayer that delivered 14 gallons of water per acre at 29 psi using TX 10 nozzles. Individual plots were 64 feet long and four rows wide. Plots were arranged in the order treatments are listed in Table 1. There was one untreated row between each plot. Mites were counted on June 23 (four days posttreatment) using a microscope. Fifteen leaves were collected from the two middle rows of each plot, placed in a zip-lock bag, transported to the lab in a cooler with ice, and inspected immediately. Mites were counted at the base of each leaf in an area between the leaf veins that was shaped like an equilateral triangle with 1 inch sides (Table 1). Aphid chemicals were applied to 38-inch row cotton using a CO2 back pack sprayer that delivered 11.34 gallons per acre at 26 psi using TX 10 nozzles. Treatments were applied on Tuesday, July 8, 2008 from 5.45 p.m. to 7.15 p.m. No wind was occurring at time of application. A total of 0.9 inches of rain fell the next afternoon. Plots were 20 feet long with two rows per plot. There were four repetitions per treatment with plots arranged in a randomized complete block design. One row was used as an untreated buffer between each plot. Aphids were counted on the third uppermost leaf from each of 10 plants per plot. Fungal disease significantly reduced aphid numbers at six days postapplication. Cotton was harvested from 10 row feet in each plot and weighed on October 22, 2008 (Table 2). The mean number of aphids counted in each of the four insecticide treatments was significantly less than that in the untreated check three days postapplication (Pr>F = 0.10, LSD = 36.4). Differences in yield could be attributed to an inconsistent stand in one of the Carbine plots and one of the Trimax Pro plots and not due to efficacy in controlling aphids. TABLE 1. EFFECTIVENESS OF INSECTICIDES IN CONTROLLING SPIDER MITES Treatment Curacron 8E Brigade 2EC Untreated Lorsban 4E Oberon 2SC Untreated Curacron 8E 1 Rate lb a.i./A 0.75 0.08 0.5 0.5 0.75 Average no. mites1 1.53 1.87 6.87 4.13 2.07 4.33 3.40 Reduction2 % 78 73 40 52 21 Number of mites per 0.36 square inch. Average for 15-leaf sample. 2 Percent reduction relative to nearest untreated plot. Treatment Check Carbine Trimax Pro Leverage acetamiprid Rate lb a.i./A 0.088 0.047 0.079 0.05 TABLE 2. EFFECTIVENESS OF INSECTICIDES IN CONTROLLING APHIDS Mean no. aphids per leaf 3 days postapplication 165 a 122 b 115 b 108 b 98 b Mean no. aphids per leaf 6 days postapplication 32 12 7 14 14 Seed cotton yield lb/A 4428 ab 4181 ab 4062 b 4987 a 4637 ab 36 ALABAMA AGRICULTURAL EXPERIMENT STATION STINK BUG RESIDUAL CONTROL WITH VARYING CLASSES OF CHEMISTRY R. H. Smith A trial established in 2008 at the Wiregrass Research and Extension Center (WREC) with a double peanut interface was utilized in a replicated study to determine the residual effectiveness of varying classes of chemistry when the treatments were made at set intervals of three, five, seven, and nine weeks of bloom. A phosphate (Bidrin) was compared to a pyrethroid (Discipline) and a combination of a pyrethroid (Karate) + a neonicotinoid (Centric). Weekly measurements of internal boll damage were made and yields taken. Approximately 56 percent of the quarter-size diameter bolls had internal stink bug injury when this trial was initiated on August 19 (third week of bloom). All treatments were applied on the same schedule (every other week) continuing from week three of bloom through week nine. Dates of application were August 19, Septmenber 2, September 16, and October 3. A total of four applications were made for each treatment. The last evaluation was made seven days following application number four. Plots were harvested on November 18. The damage in each treatment tracked relatively close together throughout the trial (see table). It could be concluded, based on the results of this test, that when stink bugs are mi- grating into cotton daily from an adjacent host crop, the spray interval is more important than the type of chemistry used. Little differences were measured between the residual of a phosphate (Bidrin), a pyrethroid (Discipline), or a tank mixture of two chemical classes (pyrethroid [Karate] and neonicotinoid [Centric]) in this trial conducted under heavy and continuous stink bug pressure. When yields were taken at maturity, some differences were noted. In each stacked replicate, the Discipline yields were lower than the other two treatments. However, some of this yield variabilty may be explained by factors other than stink bug damage. The first replicate of Bidrin that yielded 2962 pounds per acre was located on one end of the field that had soils with better moisture-holding capacity. The fourth replicate of Discipline yielding 1670 pounds per acre was located on the other end of the field, which was adjacent to another peanut field. Therefore, this plot actually had peanuts on both sides plus the end. On the average, Bidrin-treated plots yielded slightly higher while Discipline-treated plots yielded lower than the Karate + Centrictreated plots. However, based on stink bug damage recorded, these differences may not be related to stink bug control. PERCENT INTERNAL BOLL DAMAGE AND SEED COTTON YIELD, 2008 Treatment Rate oz/A 1. Bidrin 5.33 2. Discipline 4 3. Karate + Centric 5 Spray applications. ———————Week of bloom——————————— 31 4 51 6 71 8 91 10 ————————————%———————————— 56 37 47 20 13 20 23 23 56 27 40 40 13 27 20 10 56 30 43 17 13 17 23 27 Avg. weeks 4-10 26 25 24 Seed cotton lb/A 2246 1750 2091 1 2008 AU CROPS: COTTON RESEARCH REPORT 37 STINK BUG THRESHOLD VERIFICATION TRIAL (LATE PLANTING DATE) R. H. Smith The bug complex, specifically multiple stink bug species in Alabama and the southeastern U.S., has increased in importance following boll weevil eradication and the introduction of transgenic cottons. Much knowledge has been gained about stink bugs, but many questions concerning sampling, thresholds, and their movement from crop to crop or through the farmscape remain. This is particularly true concerning the interface of cotton and alternate stink bug hosts. A major objective of this project is to update and or advance management strategies for stink bugs in Alabama and the Southeast. A trial was established in 2008 at the Wiregrass Research and Extension Center in Headland, Alabama. Cotton for this trial was planted late, June 12, in order to have economic stink bug pressure throughout the entire boll production season. This would be representative of many fields planted in the coastal plains of the southeastern U.S., following a winter crop of wheat. One eight-row strip of cotton (1400 feet in length), planted with a double peanut interface, was utilized to evaluate four different threshold regimes: 20 percent internal boll damage; dynamic threshold (ranging from 10 to 50 percent boll damage, depending on the week of bloom); aggressively sprayed; and untreated. Treatments were replicated four times. Weekly boll damage counts were made and yields taken. Applications of a pyrethroid plus phosphate (Bidrin) were made to each treatment as needed from the third through the ninth week of bloom. The cotton for this trial was planted in an eight-row strip through the middle of a peanut field so that both sides of the plot would be susceptible to the movement of stink bugs from peanuts. This situation presented a worst case scenario in which to evaluate stink bug thresholds. This test was initiated the third week of bloom, as soon as some bolls reached the stage of stink bug injury susceptibility. The injury level was 52 percent internal injury on August 19 when treatments were initiated. Three weekly sprays were required in all treatments to bring stink bug damage below the 20 percent level. The 20 percent internal threshold was not treated, based on damage, for the next two weeks. However, stink bug populations rebounded and applications were required on weeks eight and nine. The dynamic threshold triggered and was sprayed four consecutive weeks (weeks three, four, five, and six). The stink bug injury in these plots never rebounded to treatable levels again, resulting in a total of only four sprays rather than five, as was made to the 20 percent internal injury threshold. The aggressively sprayed plots (applications made weekly) received a total of seven total sprays. However the seasonal injury level (averaged over the seven weeks of trial) was only slightly less than the dynamic threshold seasonal average. Both the dynamic and aggressively sprayed thresholds had slightly less damage than the 20 percent internal injury threshold. The average stink bug boll injury in the untreated, over the seven weeks of this trial, was 73 percent, which demonstrates the extremely high pressure encountered. Based on the results of this trial, conducted under a worst case situation, the dynamic threshold proved to be the most economical and efficacious treatment evaluated. Yields were taken at maturity. All threshold treatments were greatly superior to the untreated by about 2000 pounds of seed cotton per acre. Few differences were recorded between the dynamic threshold and aggressively sprayed (four total sprays versus seven). Both out-yielded the plots treated at the 20 percent injury threshold by about 200 pounds of seed cotton per acre. In summary, when considering the number of sprays needed, the level of damage incurred, and the yields, the dynamic threshold was the most economical and reasonable threshold to follow. Threshold treatment 1. Untreated 2. 20 percent internal boll damage 3. Dynamic threshold 4. Aggressively sprayed TABLE 1. DATE OF TREATMENT APPLICATIONS Application dates 8/19, 8/28, 9/2, 9/23, 9/30 8/19, 8/28, 9/2, 9/8 8/19, 8/28, 9/2, 9/8, 9/15, 9/23, 9/30 Total treatments 0 5 4 7 —————————Date and week of bloom———————— Avg. Number of 19 Aug 28 Aug 2 Sep 8 Sep 15 Sep 23 Sep 30 Sep weeks Treatment applications wk. 3 wk. 4 wk. 5 wk. 6 wk. 7 wk. 8 wk. 9 4-9 —————————————————%————————————————— 1. Untreated 0 521 58 75 70 80 82 75 73 2. 20 percent internal damage 5 522 382 382 8 2 302 222 23 3. Dynamic threshold 4 522 302 482 122 8 8 0 18 4. Aggressively sprayed 7 522 402 352 22 52 02 22 14 1 2 TABLE 2. PERCENT INTERNAL BOLL DAMAGE AND SEED COTTON YIELD, 2008 Seed cotton yield lb/A 897 2740 2964 2942 Ten quarter-size diameter bolls were collected and observed for internal injury weekly from each of four replicates. Applications made with Bidrin (4 ounces per acre) + Bifenthrin (3.2 ounces per acre). 38 ALABAMA AGRICULTURAL EXPERIMENT STATION STINK BUG THRESHOLD VERIFICATION TRIAL (NORMAL PLANTING DATE) R. H. Smith A trial to evaluate management strategies for stink bugs was established in 2008 at the Wiregrass Research and Extension Center in Headland, Alabama. Cotton utilized in this test was planted on May 15, which is within the normal planting window for southeast Alabama. Eight rows, approximately 1400 feet in length, along the border of the field interfacing with peanuts were utilized for this trial. This was done so that the plot would be susceptible to the movement of stink bugs from peanuts. This situation presented a worst case scenario under which to evaluate stink bug thresholds. Stink bug controls were initiated on August 12, about the third week of bloom, when boll damage was about 11 percent. Four threshold regimes were evaluated until there were no longer any bolls susceptible to stink bug injury. Untreated plots received no controls, while the aggressively sprayed received four. The 20 percent internal injury and dynamic threshold each received three sprays. Boll damage counts were taken weekly and few differences were noted between treated threshold regimes. By the end of the season the damage in the untreated plots reached 88 percent, which demonstrated the level of stink bug pressure experienced in this trial. Based on the results of this trial, it could be concluded that under heavy pressure, as experienced along the cotton-peanut interface border, the treatment threshold followed is not as important as long as stink bug damage is maintained to a minimal level. There was no advantage to the aggressively sprayed regime over the 20 percent or dynamic threshold. Yields were taken at maturity and followed the same trends as did the stink bug damage. All treated plots yielded more than the untreated while there were few differences in yield between the three treated regimes. It might be noted that when cotton is planted within a normal plant date window, the length of period when bolls are susceptible to stink bug injury is about three to four weeks along a cotton-peanut interface border. Threshold treatment 1. Untreated 2. 20 percent internal boll damage 3. Dynamic threshold 4. Aggressively sprayed TABLE 1. DATE OF TREATMENT APPLICATIONS Application dates Total treatments 0 8/12, 8/19, 9/2 3 8/12, 8/19, 9/2 3 8/12, 8/19, 8/27, 4 9/2 TABLE 2. PERCENT INTERNAL BOLL DAMAGE AND SEED COTTON YIELD Treatment Number of applications 0 3 3 4 1. Untreated 2. 20 percent Internal Damage 3. Dynamic Threshold 4. Aggressively Sprayed 1 2 ——Date and week of bloom—— 12 Aug 19 Aug 25 Aug 2 Sep Average wk. 3 wk. 4 wk. 5 wk. 6 damage ———————————%——————————— 111 48 40 88 59 112 202 8 152 14 112 152 3 182 12 112 202 102 202 15 Seed cotton yield lb/A 1285 2513 2627 2555 Ten quarter-size diameter bolls were collected and observed for internal injury weekly from each of four replicates. Applications made with Bidrin (4 ounces per acre) + Bifenthrin (3.2 ounces per acre). 2008 AU CROPS: COTTON RESEARCH REPORT 39 SYSTEMS TECHNOLOGY TRIAL, PRATTVILLE, ALABAMA R. H. Smith A small plot trial was conducted at the Prattville Agricultural Research Unit to compare genetically altered varieties, conventional varieties, and the new lepidopterous chemistry. Several Bt varieties were compared to conventional varieties with and without over-sprays for caterpillar pests. Delta Pine, Stoneville, and Phytogen biotech varieties were compared to conventional Delta Pine and Bronco varieties over-sprayed for bollworms and tobacco budworms. Insecticides evaluated were Coragen and Belt. Both test areas were over-sprayed as needed for bug and sucking pests. Bollworm and tobacco budworm larvae and damage counts were made. Yields were taken at maturity and plots were arranged in a randomized complete block design. Only one generation of bollworms infested this trial area in 2008. Furthermore, since the test area did not require an early season application for bug and/or sucking pests, beneficial insects were still present when the bollworm flight occurred about July 20. This minimized worm damage in this trial when compared to other trials on the same research farm that was oversprayed prior to July 20. On August 4, seven days after the initial application to treatments seven and eight, square damage was greatest in the conventional plots (treatments six, nine, and ten) that were untreated for worms. Live larvae found on the same date showed similar trends. Yields from these treatments showed quite a bit of variability between replicates. This likely was caused by the differences in moisture-holding capacity of the soil. Even though the final yields were considered good, there was an extended dry period in August which limited the yield potential of full-season varieties. In general, the varieties with Bt technology and the conventional varieties that were over-sprayed one time for worm control yielded more than the conventional varieties, where no worm control was applied. The conventional variety, Bronco 7139 unsprayed, was the lowest yielding treatment in this trial. Only moderate differences were found among any of the varieties containing the Bt gene (either single or stacked). The conventional varieties in this test were not over-sprayed prior to the July worm pressure to better reflect what growers planting conventional varieties in central Alabama are doing in their general production operations. No. damaged/ 10 squares 7 DAA1 0 0 0 0.25 0.75 2.75 0.75 1.25 4.0 5.25 No. live larvae/ 10 squares 7 DAA 0.25 0 0 0 0 1.5 0.5 0.25 0.75 0.75 Seed cotton yield lb/A 3156 3012 2964 3288 3048 2784 3180 3168 2880 2652 DAMAGE AND SEED COTTON YIELDS Variety 1. DP161 B2RF 2. DP143 B2RF 3. ST4554 B2RF 4. PHY 485 WRF 5. DP 555 BG/RR 6. DP174 RF 7. DP491 8. DP491 9. DP491 10. Bronco 7139 1 Treatment/Rate Untreated Untreated Untreated Untreated Untreated Untreated Coragen 0.088 lb/A Belt 3.0 oz/A Untreated Untreated Days after application. 40 ALABAMA AGRICULTURAL EXPERIMENT STATION SYSTEMS TECHNOLOGY TRIAL, WREC, HEADLAND, ALABAMA R. H. Smith A trial was conducted in 2008 at the Wiregrass Research and Extension Center to compare genetically altered varieties, conventional varieties, and the new lepidopterous chemistry. Several Bt varieties were compared to conventional varieties with and without over-sprays for caterpillar pests. Delta Pine, Stoneville, and Phytogen varieties were compared to conventional Delta Pine and Bronco varieties over-sprayed with all labeled chemical classes for bollworms and tobacco budworms. Insecticides evaluated were Coragen, Belt, Tracer, Steward, Denim, and Karate. The test area was over-sprayed as needed for bug and sucking pests. Bollworm and tobacco budworm larvae and damage counts were made. Yields were taken at maturity and plots were arranged in replicated adjacent strips. The first application was well timed on larvae one to four days old. Based on the species of moths observed, most of the population on July 8 was the tobacco budworm species. The second application was made one week later and the population had shifted to approximately 50 percent budworm and 50 percent bollworm. At the first evaluation (seven days after the first application), the least square damage was found in the varieties with Bt technology. The most effective over-sprays were Coragen, Tracer, and Belt. Note that a low rate of Coragen was made on application number one due to a miscalculated rate. Karate Z, as expected against budworms, was the least effective treatment and not greatly different than the untreated control. Another square damage evaluation was made (eight days after the second application). Again the overspray with Karate Z was similar to the untreated control. The varieties with Bt technology continued to show the least square damage. Only slight differences were recorded between the remaining Lepidopteron insecticides. Coragen (0.088 pounds a.i.), Steward, and Tracer had the least square damage. Based on the results of this trial, it could be concluded that Lepidoptera over-sprays, when well timed to target small larvae, can be as effective as the Bt technology in reducing damage. SQUARE DAMAGE Variety 1. PHY 485 WRF 2. DP 161 BG2RF 3. ST 4554 B2RF 4. DP 555 BG/RR 5. DP 174 RF 6. DP 174 RF 7. DP 174 RF 8. DP 174 RF 9. DP 174 RF 10. DP 174 RF 11. DP 174 RF 12. DP 174 RF 1 Insecticide ————Rate———— App. 1 App. 2 ————lb/a.i./A———— Coragen Coragen Belt Steward Tracer Denim Karate Untreated 0.0161 0.0111 2.5 oz 0.11 0.063 0.01 0.04 0.088 0.088 2.5 oz 0.11 0.063 0.01 0.04 ——Square damage—— 7 DAA#1 8 DAA#2 ———%——— 0 1 2 1 0 0 0 2 0 3 11 9 4 7 8 3 2 3 12 7 28 40 32 42 Rates were miscalculated. WEED MANAGEMENT EVALUATION OF HERBICIDES FOR PALMER AMARANTH CONTROL IN COTTON, HEADLAND, ALABAMA, 2008 M. G. Patterson Cotton, variety DPL 141 B2RF, was planted at the Wiregrass Research and Extension Center in Headland, Alabama, in early May 2008 in a field that was heavily infested with Palmer amaranth (Amaranthus palmeri). Although there are biotypes of this weed that are resistant to the ALS class of herbicides (Staple, Envoke, Cadre, Classic, etc.) and glyphosate (Roundup, etc.), the population at Headland has not shown resistance to date. Soil-applied and foliar-applied herbicides were evaluated for Palmer amaranth activity on this site. The trial site has been maintained in reduced tillage for the past 21 years. A strip till planting system was used and all production practices including soil fertility, disease, and insect control were maintained by Research Center personnel for optimum cotton production. The site was irrigated several times during the growing season using a lateral move irrigation system and specifically used to activate the PRE herbicides after planting. Lasso MT, an older herbicide not registered in cotton, was evaluated alone and in combination with Cotoran or Reflex. Lasso works using the same mode of action as Dual. In addition to the herbicides applied in the following table, the entire trial site including the untreated control was oversprayed with Roundup Weathermax at the rate of 32 fluid ounces per acre in early August after all weed control evaluations were obtained. Pigweed control from soil-applied preemergence treatments was good to excellent three weeks after planting (to four-leaf cotton). However, by seven weeks after planting without a follow up treatment of Roundup + metolachlor (Parrlay) applied at the four-leaf cotton stage the control began to decline significantly, resulting in significant yield loss (see the table). Lasso proved to be an effective and safe herbicide for soil residual control of pigweed in this trial. The results of this study clearly show that postemergence control is needed to control Palmer amaranth and obtain optimum cotton yields. In light of the development of herbicide resistant pigweed in Georgia, a logical approach would be to integrate both soil-applied and foliar herbicide programs using different modes of action to try to maintain season long control. Prowl + Reflex PRE or Prowl + Cotoran PRE followed by Roundup + metholachlor early postemergence followed by layby herbicide application would be such a program. Although this program will work in areas where glyphosate-resistant pigweed is not yet present, a program using glufosinate (Ignite) herbicide in Liberty-Link cotton may be required in fields with glyfosinate-resistant weeds. ——— Control——— ————%———— 5/28 6/13 7/17 98 90 42 97 99 97 Seed cotton lb/A 2122 3517 EVALUATION OF HERBICIDES FOR CONTROL OF PALMER AMARANTH Treatment1 Prowl + Reflex Prowl + Reflex followed by Roundup Wmax + Parrlay Prowl + Cotoran Prowl + Cotoran followed by Roundup Wmax + Parrlay Lasso + Cotoran Lasso + Cotoran followed by Roundup Wmax Lasso Untreated 1 Rate/A 2 pt + 1.5 pt 2 pt + 1.5 pt 22 oz + 1.3 pt 2 pt + 2 pt 2 pt + 2 pt 22 oz + 1.3 pt 3 pt + 2 pt 3 pt + 2 pt 22 oz + 1.3 pt 3 pt — Timing2 PPI PRE POT 4L PRE PRE POT 4L PRE PRE POT 4L PRE — 97 93 63 97 20 91 960 3549 98 94 93 0 88 98 72 0 56 83 48 0 2606 3340 1468 0 Treatments applied in 15 gallons of water per acre with flat fan nozzles. PRE treatments applied 5/7; POT 4L treatments applied 5/29. Lasso = alachlor, Reflex = fomesafen, Parrlay = metolachlor, Cotoran = fluometuron, Roundup Wmax = glyphosate. 2 PPI = preplant incorporated, PRE = preemergence, POT 4L = post over the top at four-leaf cotton stage. 42 ALABAMA AGRICULTURAL EXPERIMENT STATION RESIDUAL INFLUENCE OF PRIMARY TILLAGE ON WEED CONTROL AND COTTON YIELD M. G. Patterson and C. D. Monks Tillage systems including (1) moldboard plowing followed by disking with Prowl at 2 pints per acre followed by field cultivation, (2) disking twice with Prowl followed by field cultivation, (3) no-till with Prowl preemergence after planting, and (4) no-till without Prowl were evaluated for weed control and cotton yield over a three-year period beginning in 2006. These tillage systems were initiated in early May 2006 at the E.V. Smith Research Center. The trial was planted in Delta Pine 143 B2RF Roundup Ready Flex cotton in 2006 and 2007 and Delta Pine 141 B2RF in 2008. Preemergence herbicides including Cotoran, Caparol, or none were applied after planting. Postemergence herbicides used following preemergence herbicides included either glyphosate (Roundup Weathermax at 22 fluid ounces per acre) or none. The trial area was infested with annual grasses (goosegrass and crabgrass) and spiny pigweed. Visual weed control and seed cotton yields were obtained. The test area was replanted in 2007 and 2008 using no-till planting across the entire test area to determine the residual effects of primary tillage conducted in 2006. Weed control (not shown) and seed cotton yields in 2006 were higher overall for the plots that received moldboard plowing, regardless of the preemergence or postemergence herbicides applied after tillage operations (see the table). No-till without Prowl resulted in lower overall weed control and seed cotton yield. This tillage influence carried over somewhat to 2007 with the same trend as in 2006. Continuing the trial into 2008 shows that the yield increase attributed to primary tillage over no-till in 2006 and 2007 did not carry over into the third year. However, the advantage of applying Prowl herbicide in 2008 and previous years is evident (average 1634 pounds with Prowl versus 1110 pounds without Prowl in 2008, with an overall average yield decrease of 37 percent for the three-year period when Prowl was not used). Although preemergence herbicides provided better overall early-season control for all systems, the use of glyphosate postemergence was required for optimum weed control and cotton yield. ——2006—— ——2007—— ——2008—— Yield Change1 Yield Change Yield Change lbA % lbA % lbA % Inversion, Disk, 2713 0 2389 0 1597 0 Prowl Disk twice, 2061 -24 2064 -14 1650 +3 Prowl No-till, 1987 -27 2147 -10 1656 +3 Prowl No-till, 1442 -47 1574 -34 1110 -30 No Prowl Tillage System 1 TILLAGE EFFECTS ON SEED COTTON YIELD AVERAGED OVER HERBICIDE TREATMENTS Change % = relative to inversion, disk, prowl. 2008 AU CROPS: COTTON RESEARCH REPORT 43 EARLY SEASON PIGWEED CONTROL IN CONSERVATION TILLAGE COTTON A. J. Price, C. D. Monks, and M. G. Patterson Conservation-tillage systems are primarily used to address concerns about soil erosion, soil quality, and water availability. Cotton acreage in conservation tillage systems is estimated to be 30 percent in the U.S. and approaches 60 percent in the southeastern U.S. The use of cover crops in conservation tillage offers many advantages, one of which is weed suppression through physical barrier as well as chemical allelopathic effects. Cereal rye (Secale cereale L.) is one of the most common winter cover crops recommended for cotton production in the U.S. Recently, glyphosate resistant Palmer amaranth (Amaranthus palmeri) has been discovered in Arkansas, Georgia, North Carolina, South Carolina, and Tennessee and populations in Alabama may also be resistant. Current resistant Palmer amaranth control recommendations in Georgia rely on soil applied herbicides. However, conservation tillage systems are disadvantaged due to herbicide interception by winter cover residue. An alternative method may be to band herbicides over the drill, thus protecting cotton yield while reducing inputs. Previous research has also shown that high amounts of residue can inhibit weed germination and emergence. We hypothesize that pigweed control will be higher in high-residue systems versus low residue systems and at control levels equivalent to conventional tillage systems utilizing soil applied herbicides. Therefore, field studies were conducted evaluating pigweed density, biomass, and cotton yield provided by two tillage systems containing four winter residue amounts in the conservation tillage system and four herbicide systems. Identical field experiments were established at the E.V. Smith Research Center (EVSRC) located near Shorter, Alabama, and at the Tennessee Valley Research and Extension Center (TVREC) near Bella Mina, Alabama, in the fall of 2006 and fall 2007. The experimental design was a randomized complete block, having a split block restriction on randomization, with three treatment replicates. Native populations of Palmer amaranth and redroot pigweed (Amaranthus hybridus) were present at E. V. Smith and Tennessee Valley locations, respectively. However, an additional 120,000 seed of each respective pigweed species was broadcast early spring over each plot at each location to assure an adequate seedbank. The experiment involved two tillage systems, four winter residue amounts in the conservation-tillage system, and four herbicide regimes. Parallel strips consisted of four conservationtillage treatments: high, medium, and low amounts of cereal rye plus a winter fallow treatment, as well as a conventional tillage treatment that was left fallow prior to spring tillage. The three cereal rye residue amounts were generated by utilizing three fall planting dates: two and four weeks prior to and on the historical average first frost. The rye was established with a no-till drill at a seeding rate of 89 pounds per acre; fifty pounds of nitrogen (N) as ammonium nitrate was applied to rye in fall after establishment. Additionally, perpendicular strips consisted of four herbicide regimes: (1) S-metolachlor at 1 pound per acre applied broadcast preemergence (PRE) application followed by glyphosate at 1 pound a.i. per acre applied postemergence (POST) followed by a LAYBY application of diuron at 1 pound a.i. per acre + MSMA at 2 pounds a.i. per acre + 0.25 percent (v/v) NIS, (2) S-metolachlor at 1 pound per acre applied banded PRE followed by glyphosate at 1 pound per acre POST followed by a LAYBY application of diuron at 1 pound per acre + MSMA at 2 pounds per acre + 0.25 percent (v/v) NIS, (3) glyphosate applied at 1 pound per acre POST followed by a LAYBY application of diuron at 1 pound per acre + MSMA at 2 pounds per acre + 0.25 percent (v/v) NIS, and (4) a non-treated control. In the spring, the rye cover crop as well as weeds in the winter fallow treatment were terminated using glyphosate at 1 pound a. i. per acre and flattened prior to cotton seeding with a mechanical roller-crimper to form a dense residue mat on the soil surface. Cover biomass from each plot was measured immediately before termination; the above-ground portion of the rye cover was clipped from one randomly selected 0.25-m2 section in each plot, dried, and weighed. The cotton variety DP 555 BG/RR was seeded at E.V. Smith following within-row subsoiling all plots with a narrow-shanked parabolic subsoiler, equipped with pneumatic tires to close the subsoil channel. Subsoiling was necessary because this location had a well-developed hardpan. The cotton variety DP 444 BG/ RR was direct-seeded at Tennessee Valley. The conventional tillage treatment was prepared with multiple disk passes and cotton was seeded with a four-row planter equipped with row cleaners and double-disk openers at both locations. Both experimental areas were exposed to extreme drought, and the experimental area at E.V. Smith received minimal supplemental irrigation so that the experiment was not terminated. At both locations, plots consisted of four rows, each 25 feet long with a 40-inch row spacing. Evaluations also included pigweed density, dry weight and fresh weight before and after POST and LAYBY herbicide applications, cotton stand establishment, and height. Cotton seed lint yields were determined by machine-harvesting the middle two rows of each plot with a spindle picker. Winter Cover Crop Biomass and Weed Density. In 2007, at both locations, the highest rye biomass was attained following the earliest planting date and the lowest biomass was attained following the latest planning date. At Tennessee Valley, biomass yields of 7750, 6598, and 5742 pounds per acre were attained for planting dates one, two and three, respectively. At Tennessee Valley, the highest pigweed density (434,413 plants per acre) was observed following the winter fallow conservation-tillage (WF) treatment. The second highest densities were observed following the third planning date (199,595 plants per acre) and the conventional-tillage (CT) (226,701 plants per acre) treatments. The lowest densities followed the first (36,437 plants per acre) and second planting dates (49,798 plants per acre). At E.V. Smith, biomass yields of 7526, 5401, and 3723 pounds per acre were attained for planning dates one, two, and three, respectively. At E.V. Smith, the highest pigweed density again followed the winter fallow conservation-tillage treatment (322,672 plants per acre). The second highest density followed the conventionaltillage treatment (234,818 plants per acre). All three conserva- 44 ALABAMA AGRICULTURAL EXPERIMENT STATION tion-tillage systems provided lower densities ranging between 85,020 and 93,118 plants per acre compared to both the winter fallow conservation tillage and conventional tillage treatments. Similar to 2007, in 2008 at the Tennessee Valley location, the highest rye biomass was attained following the earliest planting date and the lowest biomass was attained following the latest planning date. At Tennessee Valley, biomass yields of 8410, 7863, and 7315 pounds per acre were attained for planting dates one, two, and three, respectively. Also similar to 2007 at Tennessee Valley, the highest pigweed density (20,918 plants per acre) was observed following the winter fallow conservation-tillage (WF) treatment. The second highest densities were observed following the conventional-tillage (CT) treatment (11,470 plants per acre). Interestingly, the lowest densities followed the third (2,025 plants per acre) and second planting dates (2,700 plants/ per acre), which both had lower cover biomass than the first planting date (4,703 plants per acre). At E.V. Smith, biomass yields of 6540, 6876, and 2374 pounds per acre were attained for planning dates one, two, and three, respectively. At E.V. Smith, the highest pigweed density again followed the winter fallow conservation-tillage treatment (44,197 plants per acre) and the conventional-tillage treatment (95,980 plants per acre). All three conservation-tillage systems provided lower densities ranging between 29,690 and 9,945 plants per acre compared to both the winter fallow conservation tillage and conventional tillage treatments. Overall, pigweed germination was substantially less in 2008 compared to 2007. Winter Cover Crop Biomass and Pigweed Biomass. In 2007 there were differences between locations; thus, pigweed species biomass response was significant. At Tennessee Valley, redroot pigweed biomass generally reflected pigweed density, with the highest pigweed biomass (240 pounds per acre) attained in winter fallow conservation tillage and conventional tillage (178 pounds per acre) treatments. Planting date three resulted in 1816 pounds biomass per acre while planting dates one and two resulted in ≤ 2.7 pounds biomass per acre. At E.V. Smith, similar Palmer amaranth biomasses were observed in the winter fallow conservation tillage (75 pounds per acre) and conventional tillage treatments (85 pounds per acre). Densities of 54 pounds per acre and 49 pounds per acre were observed in planting date treatments one and two, respectively. However, the third planning date which provided similar pigweed density compared to planning dates one and two provided the lowest pigweed bio- mass (22 pounds per acre). Because the experimental area experienced severe drought stress throughout the season, the larger pigweed in the earlier planting dates may be due to increased moisture conservation provided by the higher mulch residue attained in these treatments, resulting in larger plants. In 2007 there were differences between location; thus, pigweed species biomass response was significant. At Tennessee Valley, redroot pigweed biomass generally reflected pigweed density, with the highest pigweed biomass (467 pounds per acre) attained in winter fallow conservation tillage. The second highest biomass was attained in the highest winter cover biomass treatment (190 pounds per acre) and the conventional tillage (181 pounds per acre) treatments. Planting dates two and three resulted in similar biomass, 36 and 42 pounds biomass per acre, respectively. At E.V. Smith, the highest Palmer amaranth biomass was observed in the winter fallow conservation tillage (633 pounds per acre) treatment. The lowest biomass (82 pounds per acre) was observed in planting date two that also provided the highest biomass. Cotton Yield. In 2007 at Tennessee Valley and E.V. Smith, cotton yield was not dependent on pigweed density or pigweed biomass (data not shown). Additionally, all conservation-tillage treatments yielded more seed cotton than the conventional tillage treatment. Similar to 2007, in 2008 at Tennessee Valley and E.V. Smith, cotton yield was not dependent on pigweed density or pigweed biomass. However, the highest yield was attained under conventional tillage followed by winter fallow. Yield decreases are likely attributed to stand reductions due to hair-pinning of the rye cover crop into the seed furrow at planting. Results at E.V. Smith are similar to those observed in 2007, again cotton yield was not dependent on pigweed density or pigweed biomass. The following conclusions can be drawn: • Increasing amounts of winter cover biomass can decrease early season pigweed density in conservation-agriculture systems, thus allowing for a size differential between pigweed and crop for future herbicide applications. • Conservation-agriculture systems that do not utilize high-residue winter cover crops may have increased pigweed densities. • Weed control provided by shallow tillage is similar to conservation-agriculture systems that have moderate amounts of residue; systems with maximum levels of residue will have fewer pigweed. DISEASE MANAGEMENT EVALUATION OF SEED TREATMENT COMBINATIONS WITH SEED QUALITY FOR SEEDLING DISEASE MANAGEMENT IN COTTON IN NORTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, W. S. Gazaway, G. W. Lawrence, C. H. Burmester, and B. E. Norris Experimental seed treatments were evaluated for the management of cotton seedling disease in a naturally infested field on the Tennessee Valley Research and Extension Center in Belle Mina, Alabama. The field has a history of cotton seedling disease incidence and is colonized by Rhizoctonia solani, Pythium spp., Thielaviopsis basicola, and Fusarium spp. The soil type is a Decatur silt loam (24 percent sand, 49 percent silt, and 28 percent clay). The seed treatments were applied to the seed by Bayer to DPL 444BG/RR cotton seed. Temik 15G (5 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with a 40-inch row spacing, and were arranged in a randomized complete block design with five replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Plots were irrigated with a sprinkler system as needed. Seedling stand was determined at two and four weeks after planting on May 1 and May 15. The skip indexes were also recorded at four weeks after planting. Population densities of the nematodes were determined by taking ten soil cores, 1 inch in diameter and 6 inches deep, collected across the entire plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least sig- nificant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in mid-April through harvest in early October were 71.7, 78.4, 89.3, 91.1, 88.3, and 83.3 degrees F with average minimum temperatures of 48.9, 57.3, 65.9, 67.5, 66.4, and 63.5 degrees F, respectively. Rainfall accumulation for each month was 3.6, 4.0, 2.6, 2.3, 4.8, and 0.8 inches with a total of 18.2 inches. The drought continued in 2008 but was not as severe as in 2007. Seedling disease pressure was moderate. Plant stand was not different between any fungicide combinations or seed quality at 14 or 28 days after planting. All plant stands were within the optimum range of two to three plants per foot of row; thus, seedling disease was not severe enough to reduce the untreated controls (treatments one and five) to below two seed per foot of row. The skip index or the uniformity of the stand was improved (P≤ 0.10) in the RTU Baytan Thiram + Allegiance high seed quality (treatment two) and RTU Baytan Thiram, Allegiance, + Trilex (treatment seven) or Dynasty (treatment eight) low quality seed as compared to the untreated control high quality seed (treatment one). Seed cotton yields varied by 593 pounds per acre at harvest with an average of 4293 and 4346 pounds per acre of seed cotton produced over the fungicide treatments in the high and low seed qualities, respectively. The use of fungicides increased yield numerically by 129 pounds per acre in the high quality seed and by 119 pounds per acre in the low quality seed. YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA, 2008 No. 1 2 3 4 5 6 7 8 Treatment Untreated RTU Baytan Thiram + Allegiance TRT 2 Trilex advanced TRT 2 Dynasty CST Untreated RTU Baytan Thiram + Allegiance TRT 2 Trilex advanced TRT 2 Dynasty CST LSD (P≤ 0.10) Standard Deviation CV Seed quality High High High High Low Low Low Low —Stand/1-ft row1— 1 May 15 May 2.5 2.1 2.3 2.4 2.0 2.3 2.3 2.3 2.7 2.2 2.4 2.6 2.6 2.6 2.4 2.8 NS3 NS 4.3 5.0 18.0 20.8 Skip index2 15 May 2.3 a 1.0 b 1.8 a 2.0 a 2.0 a 1.3 a 1.0 b 1.0 b 1.1 0.9 57.7 Seed cotton lb/A 4160 4569 4325 3977 4225 4296 4361 4374 NS 480.2 11.2 Stand counted from 10 feet of row and averaged. Skip index is the uniformity of the cotton plant population across the row. Empty spaces of 1 row foot are given the value of 1 and each empty space increases the value up to 25. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 1 2 46 ALABAMA AGRICULTURAL EXPERIMENT STATION EFFICACY OF EXPERIMENTAL COMPOUNDS ON THE FUSARIUM WILT COMPLEX IN CENTRAL ALABAMA, 2008 N. S. Sekora, K. S. Lawrence, J. D. Castillo, S. R. Moore, and S. Nightengale Experimental seed treatments were evaluated for management of the fusarium wilt complex on cotton at the Plant Breeding Unit of the E. V. Smith Research Center near Tallassee, Alabama. The field site soil was Kalmia loamy sand soil type. At a soil depth of 4 inches on April 22 (day of planting), the soil temperature was 69.6 degrees F with adequate moisture. All seed treatments were applied by the manufacturer. Granular applicators attached to the planter also applied Temik 15G (5 pounds per acre) in the seed furrow at planting to all plots. All other production practices for herbicides, fertilizers, and insecticides were carried out as recommended by the Alabama Cooperative Extension System. Plots consisted of a randomized complete block arrangement of five blocks containing two 25-foot rows spaced 40 inches apart for each treatment. Nematode samples were taken by collecting ten soil cores (each 1 inch in diameter and 6 inches deep) randomly from within the rows of each plot. Nematodes were extracted from the soil samples by gravity sieving and sucrose centrifugation. Test plots were harvested on September 18. Fisher’s protected least significant difference (LSD) test was used for pairwise means comparisons and the SAS General Linear Models program was used for analysis of variance. Monthly rainfall totals for April through September were 0.13, 2.50, 1.98, 4.97, 9.92, and 0.72 inches, respectively. Total rainfall over the growing season was 20.1 inches. Average monthly maximum temperatures for April through September were 80.6, 84.5, 93.6, 92.5, 89.7, and 89.4 degrees F, respective- ly, and average minimum temperatures were 54.4, 60.9, 68.2, 70.0, 71.1, and 71.2 degrees F, respectively. Stand counts at 30 days after planting ranged from 89 to 134 plants per row within a plot. Treatment seven had a significantly higher mean stand count than treatment six and treatment nine, but it was similar to the other treatments. Vigor among treatments was similar to that of the control (data not shown). Fusarium wilt incidence was higher in treatment nine plots than treatment one, treatment six, and treatment eleven plots. The average number of plants demonstrating Fusarium wilt symptoms was 30 plants per plot with a range of three to 62 plants. Though differences in counts of M. incognita/150cm3 soil were observed at 30 days after planting, no differences were present at 114 days after planting. Harvest counts resembled those for total M. incognita over the season, so only total counts are presented. For the season, treatment three and treatment eight had significantly higher populations of M. incognita than treatment two, treatment four, treatment nine, and treatment eleven. The highest number of M. incognita per 150cm3 soil within a plot was 8343 individuals, but the average was 1945 individuals per 150cm3 across all plots for the season. Plot yields ranged from 627 to 3694 pounds per acre with a mean of 2224 pounds per acre. Treatment three had a significantly higher yield than treatment one, treatment four, treatment six, and treatment nine. Six of the eleven treatments showed similar yields to both the control and treatment three. 2008 AU CROPS: COTTON RESEARCH REPORT 47 EFFICACY OF EXPERIMENTAL COMPOUNDS ON THE FUSARIUM WILT COMPLEX IN CENTRAL ALABAMA, 2008 Treatment Cruiser 5 FS Apron XL 3 LS Maxim 4 FS Systhane 40 WP Cruiser 5 FS Apron XL 3 LS Maxim 4 FS A9625 Cruiser 5 FS Apron XL 3 LS Maxim 4 FS Systhane 40 WP A9625 Cruiser 5 FS Allegiance-FL Baytan 30 Thiram 42-S Cruiser 5 FS Allegiance-FL Baytan 30 Thiram 42-S A9625 Cruiser 5 FS Apron XL 3 LS Maxim 4 FS Systhane 40 WP Dynasty CST 125 FS A9625 Cruiser 5 FS Allegiance-FL Baytan 30 Thiram 42-S Dynasty CST 125 FS A9625 Cruiser 5 FS Allegiance-FL Baytan 30 Thiram 42-S Cruiser 5 FS Allegiance-FL Baytan 30 Trilex Flowable Apron XL 3 LS Maxim 4 FS Systhane 40 WP Cruiser 5 FS Allegiance-FL Baytan 30 Trilex Flowable Apron XL 3 LS Maxim 4 FS Systhane 40 WP A14635 Cruiser 5 FS LSD (P ≤ 0.10) Rate 0.342 7.5 2.5 21.0 0.342 7.5 2.5 1.0 0.342 7.5 2.5 21.0 1.0 0.342 15.0 10.0 31.0 0.342 15.0 10.0 31.0 1.0 0.342 7.5 2.5 21.0 0.03 1.0 0.342 15.0 10.0 31.0 0.03 1.0 0.342 15.0 10.0 31.0 0.342 15.0 10.0 10.0 7.5 2.5 21.0 0.342 15.0 10.0 10.0 7.5 2.5 21.0 20.0 0.342 Rate Unit mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg g ai/100 kg mg ai/seed Stand/ 25-ft row 20 May 108.8 ab 106.8 ab 1 2 Fusarium wilt Seed cotton incidence1 Total number of yield (lb/A) 14 Aug M. incognita/150cm3 17 Sep 23.4 b 1993 ab 1955 b 31.4 ab 1251 b 2460 ab 3 112.6 ab 36.4 ab 3368 a 2768 a 4 108.6 ab 29.7 ab 1406 b 1846 b 5 106.2 ab 33.0 ab 1916 ab 2485 ab 6 103.8 b 25.0 b 1823 ab 1972 b 7 115.4 a 30.2ab 1715 ab 2158 ab 8 111.4 ab 26.6 ab 3322 a 2179 ab 9 103.4 b 39.8 a 1514 b 1883 b 10 113.0 ab 27.4 ab 1978 ab 2287 ab 11 109.0 ab 24.2 b 1112 b 2408 ab 9.90 13.6 1713.5 737 1 Average number of plants with Fusarium wilt symptoms per plot. Means followed by the same letters are not significantly different according to Fisher’s LSD (P ≤ 0.10). 48 ALABAMA AGRICULTURAL EXPERIMENT STATION EFFICACY OF EXPERIMENTAL COMPOUNDS ON EARLY SEASON COTTON DISEASES IN NORTH ALABAMA, 2008 S. R. Moore and K. S. Lawrence Selected experimental seed treatments were evaluated to determine their efficacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, and 28 percent clay) with a history of seedling diseases. Soil temperature was 62.1 degrees F at a 4-inch depth on the day of planting, with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. For the high incidence disease trial, plots were infested with millet seed inoculated with Rhizoctonia solani and Pythium ultimum, while for the low incidence disease trial, plots were left naturally infested. Temik 15G (7.0 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. For each trial plots consisted of four rows, each 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with five replications. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used. Stand counts were recorded 21 and 35 days after planting to determine stand density and percent seedling loss resulting from cotton seedling diseases. Plots were harvested on September 30. Data were analyzed using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least significant difference (LSD) test. Seedling disease pressure was high for early planted cotton in north Alabama in 2008. At 21 days after planting, 85 per- cent of all seeds planted in the high disease pressure trial did not emerge compared to 30 percent in the low disease pressure trial. Under low disease pressure, all treatments produced cotton seedling stands comparable to the Cruiser 5 FS-treated control at 21 and 35 days after planting. Skip indices for low disease pressures were also comparable to the Cruiser 5 FS-treated control at 35 days after planting and all fungicide seed treatments yielded as well as the Cruiser 5 FS-treated control. Under high disease pressure, all treatments with the exception of treatment three (treatment one + Apron XL 3 LS + Maxim 4 FS + A9625) increased cotton seedling stands at 21 days after planting compared to the Cruiser 5 FS-treated plots. At 35 days after planting, cotton seedling stands were significantly increased by treatments five (treatment one + Allegiance FL, Baytan 30 + Thiram 42 S), seven (treatment four + Dynasty CST125 FS), eight (treatment six + Dynasty CST125 FS), nine (treatment five + Allegiance FL + Baytan 30 + Trilex Flowable), ten (treatment two + Allegiance FL + Baytan 30 + Trilex Flowable), and eleven (treatment two + A16148) compared to the Cruiser 5 FS-treated control. These treatments also produced significantly lowered skip indices compared to the Cruiser 5 FS-treated control. All fungicide seed treatments with the exception of treatment three (treatment one + Apron XL 3 LS + Maxim 4 FS + A9625) produced significantly higher yields than the Cruiser 5 FS-treated control by an average of 2613.3 pounds seed cotton per acre. 2008 AU CROPS: COTTON RESEARCH REPORT 49 Rate ——Stand/10-ft row—— unit 21 DAP1 35 DAP Low Disease Pressure 1. Cruiser 5 FS 0.34 mg/seed 22.4 a 20.4 a 2. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 27.4 a 28.0 a Systhane 40 WP + 0.21 g/kg seed Cruiser 5 FS 0.34 mg/seed 3. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 27.6 a 25.0 a A9625 + 0.01 g/kg seed Cruiser 5 FS 0.34 mg/seed 4. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 29.4 a 26.4 a Systhane 40 WP + A9625 + 0.21 + 0.01 g/kg seed Cruiser 5 FS 0.34 mg/seed 5. Allegiance-FL + Baytan 30 0.15 + 0.1 g/kg seed 26.0 a 24.8 a Thiram 42 S + 0.31 g/kg seed Cruiser 5 FS 0.34 mg/seed 6. Allegiance-FL + Baytan 30 0.15 + 0.1 g/kg seed 26.4 a 28.6 a Thiram 42 S + A9625 + 0.31 + 0.01 g/kg seed Cruiser 5 FS 0.34 mg/seed 7. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 29.4 a 29.4 a Systhane 40 WP + A9625 + 0.21 + 0.01 g/kg seed Dynasty CST125 FS + 0.03 mg/seed Cruiser 5 FS 0.34 mg/seed 8. Allegiance-FL + Baytan 30 + 0.15 + 0.1 g/kg seed 27.2 a 29.2 a Thiram 42 S + A9625 + 0.31 + 0.01 g/kg seed Dynasty CST125 FS + 0.03 mg/seed Cruiser 5 FS 0.34 mg/seed 9. Allegiance-FL + Baytan 30 + 0.15 + 0.1 g/kg seed 24.6 a 25.2 a Thiram 42 S + Allegiance-FL + 0.31 + 0.15 g/kg seed Baytan 30 + Trilex Flowable + 0.05 + 0.1 g/kg seed Cruiser 5 FS 0.34 mg/seed 10. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 28.2 a 27.8 a Systhane 40 WP + Allegiance-FL + 0.21 + 0.15 g/kg seed Baytan 30 + Trilex Flowable + 0.05 + 0.1 g/kg seed Cruiser 5 FS 0.34 mg/seed 11. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 29.4 a 26.0 a Systhane 40 WP + A16148 + 0.21 + 0.2 g/kg seed Cruiser 5 FS 0.34 mg/seed LSD (P≤ 0.10) 5.9 5.5 High Disease Pressure 1. Cruiser 5 FS 0.34 mg/seed 0e 0c 2. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 4.6 cd 3 abc Systhane 40 WP + 0.21 g/kg seed Cruiser 5 FS 0.34 mg/seed 3. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 0.2 e 1.6 bc A9625 + 0.01 g/kg seed Cruiser 5 FS 0.34 mg/seed 4. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.025 g/kg seed 4.0 d 3.8 abc Systhane 40 WP + A9625 + 0.21 + 0.01 g/kg seed Cruiser 5 FS 0.34 mg/seed 5. Allegiance-FL + Baytan 30 0.15 + 0.1 g/kg seed 6.4 abcd 5.2 ab Thiram 42 S + 0.31 g/kg seed Cruiser 5 FS 0.34 mg/seed 6. Allegiance-FL + Baytan 30 0.15 + 0.1 g/kg seed 5.4 bcd 3.8 abc Thiram 42 S + A9625 + 0.31 + 0.01 g/kg seed Cruiser 5 FS 0.34 mg/seed 7. Apron XL 3 LS + Maxim 4 FS + 0.075 + 0.02 g/kg seed 7.8 abc 7.2 a Systhane 40 WP + A9625 + 0.21 + 0.0 g/kg seed Dynasty CST125 FS + 0.03 mg/seed Cruiser 5 FS 0.34 mg/seed 8. Allegiance-FL + Baytan 30 + 0.15 + 0.1 g/kg seed 9.4 a 7.8 a Thiram 42 S + A9625 + 0.31 + 0.01 g/kg seed Dynasty CST125 FS + 0.03 mg/seed Cruiser 5 FS 0.34 mg/seed 9. Allegiance-FL + Baytan 30 + 0.15 + 0.1 g/kg seed 7.8 abc 7.6 a Thiram 42 S + Allegiance-FL + 0.31 + 0.15 g/kg seed Baytan 30 + Trilex Flowable + 0.05 + 0.1 g/kg seed Cruiser 5 FS 0.34 mg/seed Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008 Rate/seed Skip index2 Yield lb/A 3700 a 3855 a 3684 a 4016 a 4378 a 4226 a 4122 a 1.8 a 1.8 a 1.6 a 0.8 a 0.6 a 0.6 a 0.4 a 1.0 a 4095 a 0.6 a 4239 a 1.0 a 4134 a 0.6 a 1.1 9.8 a 8.8 ab 8.8 ab 7.6 ab 6.8 b 7.8 ab 6.8 b 4342 a 570 0e 1549 cd 508 de 1875 bcd 1850 bcd 2255 abc 3637 a 6.2 b 3492 ab 6.4 b 2727 abc continued 50 ALABAMA AGRICULTURAL EXPERIMENT STATION Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008, CONT. Rate ——Stand/10-ft row—— unit 21 DAP1 35 DAP High Disease Pressure, cont. 0.075 + 0.025 g/kg seed 8.6 ab 5.0 ab 0.21 + 0.15 g/kg seed 0.05 + 0.1 g/kg seed 0.34 mg/seed 0.075 + 0.025 g/kg seed 8.6 ab 7.2 a 0.21 + 0.2 g/kg seed 0.34 mg/seed 2.4 2.7 Rate/seed Skip index2 Yield lb/A 3005 abc 10. Apron XL 3 LS + Maxim 4 FS + Systhane 40 WP + Allegiance-FL+ Baytan 30 + Trilex Flowable + Cruiser 5 FS 11. Apron XL 3 LS + Maxim 4 FS + Systhane 40 WP + A16148 + Cruiser 5 FS LSD (P≤ 0.10) 1 7.4 ab 6.2 b 1.6 3131 abc 1000 Days after planting. 2 Skip index indicates uniformity of plants in the row, calculated as the total length of row without plants at 35 DAP. Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 51 EFFICACY OF COMBINATION SEED TREATMENTS ON EARLY SEASON COTTON DISEASES IN NORTH ALABAMA, 2008 S. R. Moore and K. S. Lawrence Selected seed treatment combinations were evaluated to determine their efficacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, and 28 percent clay) with a history of seedling diseases. Soil temperature was 62.1 degrees F at a 4-inch depth on the day of planting, with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. Temik 15G (7.0 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. Each plot consisted of four rows, each 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with five replications. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used. Stand counts were recorded 21 and 35 days after planting to determine stand density and percent seedling loss. Plots were harvested on September 30. Data were analyzed by using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least significant difference (LSD) test. Seedling disease pressure was high for early planted cotton in north Alabama in 2008. At 21 days after planting, 55 percent of all seeds planted did not emerge. All fungicide seed treatments produced significantly higher cotton seedling stands in comparison to the untreated check at 21 days after planting with no significant differences among seed treatments. At 35 days after planting, all fungicide seed treatments produced cotton seedling disease stands statistically comparable to the untreated check. Treatments four (treatment two + Trilex FL + Baytan 30 + Allegiance FL) and five (treatment two + Dynasty CST) had significantly lower skip indices compared to the untreated check. Yields were significantly increased over the untreated check by treatments six (treatment three + Vortex FL) and eight (treatment two + Vortex FL + Baytan 30 + Allegiance FL) by an average of 1045 pounds seed cotton per acre All other treatments produced yields comparable to the untreated check. Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008 Rate/seed Rate unit ——Stand/10-ft row—— 21 DAP1 35 DAP 10.8 b 13.4 a 17.0 a 18.4 a 18.2 a 17.6 a 21 a 16.8 a 18.0 a 21.6 a 20.0 a 19.0 a 1. Untreated 2. RTU Baytan Thiram + Allegiance FL 3. RTU Baytan Thiram + Allegiance FL + Trilex Advanced FS300 4. RTU Baytan Thiram + Allegiance FL + Trilex FL + Baytan 30 + Allegiance FL 5. RTU Baytan Thiram + Allegiance FL + Dynasty CST 6. RTU Baytan Thiram + Allegiance FL + Trilex Advanced FS300 + Vortex FL 7. RTU Baytan Thiram + Allegiance FL + Trilex Advanced FS300 + Kodiak FL 8. RTU Baytan Thiram + Allegiance FL + Vortex FL + Baytan 30 + Allegiance FL LSD (P ≤ 0.10 1 1.9 0.47 1.9 0.47 1.0 1.9 0.47 + 0.4 0.16 + 0.47 1.9 0.47 + 2.5 1.9 0.47 1.0 0.12 1.9 0.47 1.0 0.31 1.9 0.47 + 0.12 0.16 + 0.16 g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed g/kg seed Skip index2 4.0 a 2.4 ab 2.6 ab 1.4 b Yield lb/A 3263 b 4026 ab 3743 ab 4024 ab 3995 ab 4291 a 1.2 b 2.2 ab 20.0 a 16.6 a 2.6 ab 3952 ab 17.6 a 4.1 18.4 a 4.4 1.8 ab 1.4 4580 a 518 Days after planting. 2 Skip index indicates uniformity of plants in the row, calculated as the total length of row without plants at 35 DAP. Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 52 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF THE EXPERIMENTAL COMPOUND V-10116 ON EARLY SEASON COTTON DISEASES IN NORTH ALABAMA, 2008 S. R. Moore and K. S. Lawrence Selected experimental seed treatments were evaluated to determine their efficacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, and 28 percent clay) with a history of seedling diseases. Soil temperature was 62.1 degrees F at a 4-inch depth on the day of planting, with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. For the high incidence disease trial, plots were infested with millet seed inoculated with Rhizoctonia solani and Pythium ultimum, while for the low incidence disease trial, plots were left naturally infested. Temik 15G (7.0 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. For each of the low and high disease pressure trials, each plot consisted of four rows, each 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with five replications. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used. Stand counts were recorded 21 and 35 days after planting (DAP) to determine stand density and percent seedling loss. Plots were harvested on September 30. Data were analyzed by using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least significant difference (LSD) test. Seedling disease pressure was high for early planted cotton in north Alabama in 2008. At 21 days after planting, 89 percent of all seeds planted in the high disease pressure trial did not emerge compared to 45 percent in the low disease pressure trial. Under low disease pressure, all fungicide seed treatments produced comparable cotton seedling stands at 21 and 35 days after planting, as well as comparable skip indices at 35 days after planting. There were no significant differences in yields in the low disease pressure trials. Under high disease pressure, treatment eight (V-10182 + V-10209) produced significantly higher cotton seedling stands than all other treatments at 21 days after planting with the exception of treatment ten (V10178 + treatment five). At 35 days after planting, treatment eight (V-10182 + V-10209) again produced significantly higher cotton seedling stands than all other treatments. Treatment ten (V10178 + treatment five) produced significantly higher cotton seedling stands than treatments six (V-10116 + V-10209) and seven (V-10116 + V10209). Skip indices taken at 35 days after planting were comparable to the untreated check for all fungicide seed treatments. Yields were significantly higher for treatment eight (V-10182 + V-10209) than all other treatments by an average of 3114.1 pounds seed cotton per acre. Treatment ten (V10178 + treatment five) and treatment six (V-10116 + V-10209) yielded significantly higher than all other treatments by an average of 2358 pounds seed cotton per acre. 2008 AU CROPS: COTTON RESEARCH REPORT 53 Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008 Rate/seed Rate ——Stand/10-ft row—— unit 21 DAP1 35 DAP Low Disease Pressure 18.6 18.0 g/kg seed 18.2 20.0 g/kg seed 21.2 20.0 g/kg seed 21.2 21.4 g/kg seed 24.8 24.6 g/kg seed 17.8 17.8 g/kg seed 20.6 19.4 g/kg seed 22.0 24.0 g/kg seed 22.0 18.2 g/kg seed 22.0 23.6 g/kg seed g/kg seed 23.4 22.6 NS3 NS High Disease Pressure 0.2 d 1.0 d g/kg seed 2.2 cd 2.8 cd g/kg seed 0.0 d 0.8 d g/kg seed 3.4 cd 3.6 cd g/kg seed 2.8 cd 3.8 cd g/kg seed 5.8 bc 5.6 bc g/kg seed 5.6 bc 5.8 bc g/kg seed 10.0 a 13.6 a g/kg seed 3.0 cd 2.4 cd g/kg seed 9.2 ab 8.8 b g/kg seed g/kg seed 5.6 bc 3.2 cd 2.6 2.7 Skip index2 2.8 3.2 2.8 1.6 0.4 3.2 3.0 0.8 2.8 1.6 2.8 NS 8.8 7.6 8.6 8.0 7.6 8.4 8.2 7.0 7.8 8.4 6.6 NS Yield lb/A 3304 4295 3538 4103 3871 3708 3960 4158 3838 4358 4133 NS 233 f 836 ef 187 f 1324 def 2107 cde 2855 bc 2260 cd 4757 a 1459 def 3601 b 1566 def 883 1. Untreated 2. Baytan 30 3. Allegiance FL 4. Baytan 30 + Allegiance FL 5. V-10116 + V-10209 6. V-10116 + V-10209 7. V-10116 + V-10209 8. V-10182 + V-10209 9. V-10178 + V-10209 10. V-10178 + V-10116 + V-10209 11. V-10202 + V-10209 LSD (P≤ 0.10) 1. Untreated 2. Baytan 30 3. Allegiance FL 4. Baytan 30 + Allegiance FL 5. V-10116 + V-10209 6. V-10116 + V-10209 7. V-10116 + V-10209 8. V-10182 + V-10209 9. V-10178 + V-10209 10. V-10178 + V-10116 + V-10209 11. V-10202 + V-10209 LSD (P≤ 0.10) 1 2 0.1 0.15 0.1 + 0.15 0.1 + 0.15 0.15 + 0.15 0.2 + 0.15 0.15 + 0.15 0.5 + 0.15 0.5 + 0.1 0.15 0.1 + 0.15 0.1 0.15 0.1 + 0.15 0.1 + 0.15 0.15 + 0.15 0.2 + 0.15 0.15 + 0.15 0.5 + 0.15 0.5 + 0.1 0.15 0.1 + 0.15 Days after planting. Skip index indicates uniformity of plants in the row, calculated as the total length of row without plants at 35 DAP. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 54 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF THE EXPERIMENTAL COMPOUND V-10190 ON EARLY SEASON COTTON DISEASES IN NORTH ALABAMA, 2008 S. R. Moore and K. S. Lawrence Selected experimental seed treatments were evaluated to determine their efficacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, and 28 percent clay) with a history of seedling diseases. Soil temperature was 62.1 degrees F at a 4-inch depth on the day of planting with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. For the high incidence disease trial, plots were infested with millet seed inoculated with Rhizoctonia solani and Pythium ultimum, while for the low incidence disease trial, plots were left naturally infested. Temik 15G (7.0 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. For each trial, each plot consisted of four rows, each 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with five replications. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used. Stand counts were recorded 21 and 35 days after planting to determine stand density and percent seedling loss. Plots were harvested on September 30. Data were analyzed by using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least significant difference (LSD) test. Seedling disease pressure was high in north Alabama for early planted cotton in 2008. At 21 days after planting, 93 percent of all seed planted in high disease pressure trials did not emerge compared to 44 percent in the low disease pressure trial. Under low disease pressure, all fungicide seed treatments were comparable to the untreated check in cotton seedling stands at 21 and 35 days after planting, as were skip indices at 35 days after planting. Seed cotton yields were comparable to the untreated check for all treatments. Under high disease pressure, treatment four (Baytan 30 + Allegiance) and treatment seven (V-10116 + V-10209) had significantly higher cotton seedling stands at 21 days after planting. All fungicide seed treatments had cotton seedling stands and skip indices comparable to the untreated check at 35 days after planting. Yields were improved by the experimental treatment seven (V-10116 + V-10209), which was comparable to the industry standard treatment four (Baytan 30 + Allegiance). Treatments two (Baytan 30), four (treatment one + treatment two), five (V-10178 + V-10209), six (V-10178 + V-10208), eleven (V-10182 + V-10209), and twelve (V-10182 + V-10209) produced similar yields, averaging an increase of 1484 pounds seed cotton per acre. Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008 Rate/seed Rate ——Stand/10-ft row—— unit 21 DAP1 35 DAP Low Disease Pressure 19.6 19.8 g/kg seed 24.6 22.0 g/kg seed 19.6 20.8 g/kg seed 21.2 21.2 g/kg seed 23.0 26.4 g/kg seed 21.4 24.0 g/kg seed 21.2 22.6 g/kg seed 22.2 18.6 g/kg seed 19.8 21.8 g/kg seed 20.2 23.8 g/kg seed 24.0 25.6 g/kg seed 19.4 22.2 NS3 NS High Disease Pressure 0.2 c 2.0 g/kg seed 3.2 abc 1.6 g/kg seed 0.2 c 2.4 g/kg seed 5.6 a 1.8 g/kg seed 3.8 abc 1.4 g/kg seed 3.4 abc 1.0 g/kg seed 6.0 a 1.2 g/kg seed 0.4 c 1.6 g/kg seed 0.8 bc 1.4 g/kg seed 0.6 bc 1.6 g/kg seed 4.2 ab 1.4 g/kg seed 3.2 abc 2.0 2.2 NS Skip index2 Yield lb/A 4553 4161 4162 4432 4284 4418 4158 4173 3945 4323 3988 4610 NS 165 c 2019 ab 349 c 2397 ab 1969 ab 1513 b 2645 a 381 c 457 c 618 c 15496 b 1818 ab 628 1. Untreated 2. Baytan 30 3. Allegiance FL 4. Baytan 30 + Allegiance FL 5. V-10178 + V-10209 6. V-10178 + V-10208 7. V-10116 + V-10209 8. V-10190 + V-10209 9. V-10190 + V-10209 10. V-10190 + V-10209 11. V-10182 + V-10209 12. V-10182 + V-10209 LSD (P≤ 0.10) 1. Untreated 2. Baytan 30 3. Allegiance FL 4. Baytan 30 + Allegiance FL 5. V-10178 + V-10209 6. V-10178 + V-10208 7. V-10116 + V-10209 8. V-10190 + V-10209 9. V-10190 + V-10209 10. V-10190 + V-10209 11. V-10182 + V-10209 12. V-10182 + V-10209 LSD (P≤ 0.10) 1 2 0.1 0.15 0.1 + 0.15 0.5 + 0.15 0.5 + 0.15 0.1 + 0.15 0.1 + 0.15 0.15 + 0.15 0.2 + 0.15 0.1 + 0.15 0.2 + 0.15 0.2 3.0 2.8 2.4 3.6 3.6 4.0 1.6 0.8 0.8 3.6 2.8 NS 10.0 7.6 9.6 7.8 7.4 20.6 7.0 10.0 9.8 9.4 8.0 8.0 NS 0.1 0.15 0.1 + 0.15 0.5 + 0.15 0.5 + 0.15 0.1 + 0.15 0.1 + 0.15 0.15 + 0.15 0.2 + 0.15 0.1 + 0.15 0.2 + 0.15 Days after planting. Skip index indicates uniformity of plants in the row, calculated as the total length of row without plants at 35 DAP. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 55 EVALUATION OF THE EXPERIMENTAL COMPOUND V-10208 ON EARLY SEASON COTTON DISEASES IN NORTH ALABAMA, 2008 S. R. Moore and K. S. Lawrence Selected experimental seed treatments were evaluated to determine their efficacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, and 28 percent clay) with a history of seedling diseases. Soil temperature was 62.1 degrees F at a 4-inch depth on the day of planting, with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. For the high incidence disease trial, plots were infested with millet seed inoculated with Rhizoctonia solani and Pythium ultimum, while for the low incidence disease trial, plots were left naturally infested. Temik 15G (7.0 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. For each of the low and high disease pressure trials, each plot consisted of four rows, each 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with five replications. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used. Stand counts were recorded 21 and 35 days after planting to determine stand density and percent seedling loss. Plots were harvested on September 30. Data were analyzed by using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least significant difference (LSD) test. Seedling disease pressure was high for early planted cotton in north Alabama in 2008. At 21 days after planting, 97 percent of all seeds planted in the high disease pressure trial did not emerge, compared to 38 percent in the low disease pressure trial. Under low disease pressure, all fungicide seed treatments produced cotton seedling stands comparable to the untreated check. Cotton seedling stand and skip indices at 35 days after planting were comparable for all treatments, as were seed cotton yields. Under high disease pressure, treatment nine (V-10230 100 FS 0.55 g/kg seed) and treatment ten (V-10230 100 FS 0.65 g/kg seed) produced significantly higher cotton seedling stands than all other treatments at 21 and 35 days after planting. Skip indices at 35 days after planting were comparable for all treatments. Treatments nine (V-10230 100 FS 0.55 g/kg seed) and ten (V-10230 100 FS 0.65 g/kg seed) produced significantly higher yields than all other treatments. Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008 Rate/seed Rate ——Stand/10-ft row—— unit 21 DAP1 35 DAP Low Disease Pressure 22.2 ab 18.8 g/kg seed 28.8 a 23.4 g/kg seed 22.2 ab 20.6 g/kg seed 20.4 b 20.6 g/kg seed 22.2 ab 21.0 g/kg seed 25.6 ab 21.4 g/kg seed 23.2 ab 22.4 g/kg seed 28.6 a 23.2 g/kg seed 23.2 ab 19.2 g/kg seed 24.6 ab 20.6 g/kg seed 22.2 ab 22.4 g/kg seed 21.2 b 18.6 g/kg seed 24.4 ab 24.0 4.0 NS3 High Disease Pressure 0.8 b 0.4 b g/kg seed 0.2 b 0.4 b g/kg seed 0.8 b 0.6 b g/kg seed 0.6 b 0.6 b g/kg seed 0.4 b 0.4 b g/kg seed 0.2 b 0.6 b g/kg seed 0.2 b 0b g/kg seed 0b 0b g/kg seed 4.4 a 3.2 a g/kg seed 3.4 a 2.8 a g/kg seed 1.0 b 0.6 b g/kg seed 0.4 b 0.2 b g/kg seed 0.8 b 0.6 b 1.0 1.0 Skip index2 Yield lb/A 4038 3926 4261 4255 3954 4186 3965 4085 4115 4099 4209 3793 4270 NS 158 b 0b 118 b 157 b 80 b 123 b 0.0 b 0.0 b 1382 a 1358 a 170 b 61 b 196 b 549 1. Untreated 2. Allegiance FL 3. V-10208 3.6 FS 4. V-10208 3.6 FS 5. V-10208 3.6 FS 6. V-10208 3.6 FS 7. V-10208 3.6 FS 8. V-10208 3.6 FS 9. V-10230 100 FS 10. V-10230 100 FS 11. V-10280 100 FS 12. V-10280 0.83 SC 13. V-10231 100 FS LSD (P≤ 0.10) 1. Untreated 2. Allegiance FL 3. V-10208 3.6 FS 4. V-10208 3.6 FS 5. V-10208 3.6 FS 6. V-10208 3.6 FS 7. V-10208 3.6 FS 8. V-10208 3.6 FS 9. V-10230 100 FS 10. V-10230 100 FS 11. V-10280 100 FS 12. V-10280 0.83 SC 13. V-10231 100 FS LSD (P≤ 0.10) 1 2 0.15 0.05 0.075 0.1 0.15 0.2 0.25 0.55 0.65 0.15 0.15 0.15 3.0 0.8 1.6 1.8 2.0 1.4 1.6 1.8 2.4 1.8 1.2 2.8 2.4 NS 10.0 10.0 9.6 10.0 10.0 9.8 10.0 9.8 8.8 8.8 9.8 10.0 10.0 NS 0.15 0.05 0.075 0.1 0.15 0.2 0.25 0.55 0.65 0.15 0.15 0.15 Days after planting. Skip index indicates uniformity of plants in the row, calculated as the total length of row without plants at 35 DAP. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 56 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF COTTON SEEDLING DISEASE MANAGEMENT IN NORTH ALABAMA, 2008 S. R. Moore and K.S. Lawrence Selected seed treatments were evaluated to determine their efficacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, and 28 percent clay) with a history of seedling diseases. Soil temperature was 62.1 degrees F at a 4-inch depth on the day of planting, with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. For the high incidence disease trial, plots were infested with millet seed inoculated with Rhizoctonia solani and Pythium ultimum, while for the low incidence disease trial, plots were naturally infested. Temik 15G (7 pounds per acre) was applied at planting on April 15 in the seed furrow with chemical granular applicators attached to the planter. For each of the low and high disease pressure trials, each plot consisted of four rows, each 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with five replications. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used. Stand counts were recorded 21 and 35 days after planting to determine stand density and percent seedling loss. Plots were harvested on September 30. Data were analyzed by using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least significant difference (LSD) test. Seedling disease pressure was high in north Alabama for early planted cotton in 2008. At 21 days after planting, 88 percent of all seed planted in the high disease pressure trials did not emerge compared to 57 percent in the low disease pressure trial. Under low disease pressure, treatment two (Baytan 30 + Allegiance FL + Vortex FL) produced significantly higher cotton seedling stand than the untreated check, while all other treatments were comparable to the untreated check at 21 days after planting. At 35 days after planting, treatment five (treatment four + Trilex FL) produced significantly higher cotton seedling stands than the untreated check while all other treatments were comparable to the untreated check. Skip indices for treatments four (Baytan 30 + Allegiance FL +Vortex FL), five (treatment four + Trilex FL), and six (Dynasty CST) were significantly lower than the untreated check at 35 days after planting. Yields averaged 688.5 pounds seed cotton per acre higher than the untreated check. Under high disease pressure, all fungicide seed treatments produced significantly higher cotton seedling stands than the untreated check at 21 and 35 days after planting. Skip indices at 35 days after planting were comparable to the untreated check. All fungicide seed treatments produced significantly higher yields than the untreated check at an average of 2233.2 pounds seed cotton per acre. Treatment YIELD, SKIP INDEX, AND STAND COUNT OF COTTON IN NORTH ALABAMA TRIAL, 2008 Rate/seed Rate ——Stand/10-ft row—— unit 21 DAP1 35 DAP Low Disease Pressure 11.6 b 13.6 b g/kg seed 20.4 a 20.6 ab g/kg seed g/kg seed 18.0 ab 20.6 ab g/kg seed g/kg seed g/kg seed 16.2 ab 19.8 ab g/kg seed g/kg seed 18.2 ab 22.2 a g/kg seed g/kg seed 14.4 ab 20.6 ab 5.1 4.9 High Disease Pressure 0.4 d 0.4 c g/kg seed 4.6 bc 4.0 b g/kg seed g/kg seed 6.2 ab 4.0 b g/kg seed g/kg seed g/kg seed 6.8 ab 6.8 a g/kg seed g/kg seed 7.4 a 7.2 a g/kg seed g/kg seed 3.2 c 2.6 b 1.8 1.4 Skip index2 Yield lb/A 505 4205 4017 4317 4115 4314 NS3 53 d 2002 b 2536 a 3002 a 2888 a 970 c 520 1. Untreated 2. Baytan 30 + Allegiance FL + Vortex FL 3. Trilex Advanced FS 300 + Baytan 30 + Allegiance FL + Vortex FL 4. Baytan 30 + Allegiance FL + Vortex FL 5. V Baytan 30 + Allegiance FL + Vortex FL + Trilex FL 6. Dynasty CST LSD (P≤ 0.10) 1. Untreated 2. Baytan 30 + Allegiance FL + Vortex FL 3. Trilex Advanced FS 300 + Baytan 30 + Allegiance FL + Vortex FL 4. Baytan 30 + Allegiance FL + Vortex FL 5. V Baytan 30 + Allegiance FL + Vortex FL + Trilex FL 6. Dynasty CST LSD (P≤ 0.10) 1 0.104 + .155 0.025 0.05 0.104 + .155 0.025 0.207 + .31 0.5 0.207 + .31 0.5 + 0.05 0.32 4.0 a 2.2 ab 2.2 ab 1.8 b 1.2 b 1.4 b 1.5 6.4 a 7.6 a 7.4 a 6.2 a 6.2 a 8.2 a 2.4 0.104 + .155 0.025 0.05 0.104 + .155 0.025 0.207 + .31 0.5 0.207 + .31 0.5 + 0.05 0.32 Days after planting. Skip index indicates uniformity of plants in the row, calculated as the total length of row without plants at 35 DAP. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). NEMATODE MANAGEMENT PERFORMANCE OF SELECTED COTTON VARIETIES AGAINST THE ROOT-KNOT NEMATODE IN CENTRAL ALABAMA, 2008 N. S. Sekora, K. S. Lawrence, J. D. Castillo, S. R. Moore, C. H. Burmester, and S. Nightengale Cotton varieties were tested to determine yield response to root-knot nematode. The field site at the Plant Breeding Unit of the E.V. Smith Research Center had Kalmia loamy sand soil type. At a 4-inch soil depth on April 22 (day of planting), soil temperature was 69.6 degrees F with adequate moisture. The manufacturer applied all fungicide seed treatments. All other treatments were applied at planting with a chemical applicator, and Temik 15G (5 pounds per acre) was applied in the seed furrow by granular applicators attached to the planter. Plots consisted of a randomized complete block arrangement of two 25-foot rows spaced 40 inches apart. Nematode samples were taken by randomly collecting ten soil cores (each 1 inch in diameter and 6 inches deep) from the two rows of each plot. Nematodes were extracted from the soil samples by gravity sieving and sucrose centrifugation. All other production practices for herbicides, fertilizers, and insecticides were carried out as recommended by the Alabama Cooperative Extension System. Plots were harvested on September 17. The SAS General Linear Models program was used for analysis of variance, and Fisher’s protected least significant difference (LSD) test was used for paired-means comparisons. Monthly average minimum temperatures were 54.4, 60.9, 68.2, 70.0, 71.1, and 71.2 degrees F, respectively; average maximum temperatures for April through September were 80.6, 84.5, 93.6, 92.5, 89.7, and 89.4 degrees F, respectively. Monthly rainfall totals for April through September were 0.13, 2.50, 1.98, 4.97, 9.92, 0.72 inches, respectively. Total rainfall over the growing season was 20.1 inches. Moderate conditions for M. incognita disease severity were present this year. At 28 days after planting, stand counts were significantly higher for DP 162 B2RF, DP 174 RF, and DP 161 B2RF than both DP 147 RF and DP 444 BG/RR. No significant difference among varieties was observed in vigor at 28 days after planting. Numbers of M. incognita/150cm3 soil were similar among varieties throughout the growing season. The average number of M. incognita at the end of the season was 303 nematodes/150cm3 of soil. Plot yields ranged from 1162 to 3189 pound per acre with a mean of 2125 pounds per acre. Yield for DP 174 RF was significantly higher than DP 147 RF, but not so from the remaining treatments. Though not significantly different, DP 174 RF also had the lowest populations of M. incognita at harvest and the lowest total population over the season. PERFORMANCE OF SELECTED COTTON VARIETIES AGAINST THE ROOT-KNOT NEMATODE IN CENTRAL ALABAMA, 2008 Variety 1. DP 147 RF 2. DP 162 B2RF 3. DP 174 RF 4. DP 161 B2RF 5. DP 444 BG/RR LSD (P ≤ 0.10) 1 Stand/ 25-ft row 20 May 77.4 b 89.0 a 82.2 a 87.8 a 71.0 b 9.09 Vigor1 20 May 2.4 2.4 3.0 3.0 2.6 0.64 Total number of nematodes/150cm3 M. incognita M. incognita 20 May 8 Aug 46.4 77.3 15.5 170.0 46.4 155.0 15.5 139.1 46.4 108.2 61.2 97.6 M. incognita 17 Sep 370.8 216.3 185.4 293.6 448.1 281.1 Seed yield lb/A 17 Sep 1741 b 2180 ab 2477 a 2308 ab 1920 ab 610 Vigor ratings based on 1-5 scale, one being least vigorous and 5 being the most vigorous. Means followed by the same letters are not significantly different according to Fisher’s LSD (P ≤ 0.10). 58 ALABAMA AGRICULTURAL EXPERIMENT STATION ON-FARM FIELD TRIALS TO TEST THE EFFECTIVENESS OF SEED NEMATACIDES FOR MANAGING RENIFORM AND ROOT-KNOT NEMATODES ON COTTON IN ALABAMA L. Kuykendall, J. Clary, W. C. Birdsong, B. Dillard, C. D. Monks, and D. P. Delaney Cotton yield-reducing levels of both reniform and rootknot nematodes continue to infest and grow in all major cotton growing areas of Alabama. Cotton yield loss is variable but is documented to be significant. Except in severe stress conditions, yield loss from nematode damage is not visible. Seed-applied nematacide treatments are gaining popularity with growers as they have only been commercially available for one and four years for Aeris and Avicta, respectively. The question remains: Are seed-applied nematacides a viable alternative to the proven and traditional nematacides of 3 to 5 gallons of Telone and 5 to 7 pounds Temik in furrow? When conducted with objective and non-biased tests, onfarm large plot cotton nematode trials give growers, extension agents and spectialist, consultants, and suppliers a basis for making nematode management decision. Fields for these trials with selected farmer cooperators were sampled prior to planting to confirm nematode pressure. All trial fields chosen had very high populations of either reniform or root-knot nematodes, except the E.V. Smith trial which had a moderate population level. Seed from the same seed lot was used for all treatments within each trial. Gaucho Grande was included as an untreated check treatment with no nematicide claims. All test treatments were planted in three to four randomized replications per location. Due to stand problems following flooding conditions, the E.V. Smith trial was not weighed at harvest. In general all locations had enough soil moisture to achieve an adequate stand; all locations had varied dry conditions that dictated the crop response to the late summer tropical moisture. Cotton yields ranged from below average to outstanding. The Walt Corcoran and the Mark and Ron Taylor trials exhibited a numerical spread of 145 and 73 pounds lint cotton respectively between the treatments. The Richard Edgar and Carl and Paul Taylor trials showed little change between the treatments with lint cotton yield. The two-year average does show an advantage of the seed nematicide treatments when compared to the standard 5 pounds of Temik and untreated check treatments. Longer term studies over many years and trials still favor the proven and traditional nematicide treatments of 5 pounds Temik and 3 to 5 gallons of Telone when compared to an untreated non-nematicide check. However these data give more promise to the seed nematicide treatments as an alternative to the traditional proven nematicide treatments. Nematode Nematodes/ Species 100cm3 soil Root-knot Reniform 1030 Reniform 3686 Reniform 2282 Root-knot 55 Planting Date 4/23/08 5/6/08 4/22/08 4/22/08 5/22/08 Harvest Date 10/21/08 10/20/08 10/29/08 10/3/08 NA TABLE 1. LOCATION OF TRIALS, NEMATODE INFORMATION, AND PLANTING AND HARVEST DATES Farmer Cooperator Walt Corcoran Richard Edgar Carl and Paul Taylor Mark and Ron Taylor E.V. Smith County Barbour Elmore Elmore Elmore Macon Extension Agronomist William Birdsong/Brandon Dillard Leonard Kuykendall Leonard Kuykendall/Jeff Clary Leonard Kuykendall/Jeff Clary Leonard Kuykendall/Jeff Clary Variety DP555BR DP143B2RF DP164B2RF DP164B2RF DP555BR FarmerNo. Cooperator reps. Richard Edgar 3 Carl & Paul Taylor 4 Mark & Ron Taylor 3 Walt Corcoran 4 Average Two-year average1 1 TABLE 2. POUNDS LINT COTTON PER ACRE: CHANGE FROM UTC (UNTREATED CHECK) Gaucho UTC Aeris 548 -12 996 +4 1417 + 48 936 +117 + 39 + 61 Avicta +9 + 19 -5 -28 -1 + 17 Temik 5 lb +9 - 28 - 25 +62 +5 +6 Same field in 2007, except Edgar is adjoining field 2008 AU CROPS: COTTON RESEARCH REPORT 59 COTTON RESPONSE TO NEMOUT® FOR RENIFORM NEMATODE MANAGEMENT IN SOUTH ALABAMA, 2008 J. D. Castillo, K. S. Lawrence, S. R. Moore, and J. R. Akridge This trial was conducted to determine cotton response to the biological nematicide NemOut® (Paecilomyces lilacinus strain 251) to control the reniform nematode (Rotylenchulus reniformis). The test was carried out near Huxford, Alabama. Two-row plots were arranged in a randomized complete block design with seven treatments and six repetitions. The chemical nematicide standards were applied at cotton planting on May 29, 2008, and NemOut® was applied at the three- to seven-cotton leaf stage. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Stand and vigor evaluations were recorded at 34 days after planting on June 4. Stand counts were made on the number of plants in a 10-foot row and vigor evaluations were visually rated on a 1 to 5 visual scale, where 1 represents a poor vigor and 5 represents highest vigor. Soil samples were taken from each plot at 34, 63, 96, and 155 days after planting. A 150 cm³ subsample from each plot was processed and reniform nematodes were extracted by the sucrose centrifugation-flotation methods, and counted under the inverted microscope. Entire plots were harvested mechanically 150 days after planting on October 13. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test. Seasonal rainfall and temperature were generally good for the cropping period. Monthly average maximum temperatures from June to September were 93.4, 92.8, 93.5, and 88 degrees F, and average minimum temperature were 69.2, 71.4, 71.4, and 67.3 degrees F. Total rainfall from June to September was 7.3, 5, 9.4, and 1.7 inches. The total rainfall for the growing season was 23.5 inches. In the stand and vigor evaluations there were no differences between the treatments. Initial populations of the reniform nematode were low for all the treatments. In the evaluation 63 days after planting, populations of reniform nematode from the treatment with Avicta at 0.15 g.a.i./seed (treatment three), were higher than the treatment with Temik 15G + NemOut® at 0.10 pound per acre (treatment four). However, 96 days after planting, treatment with Temik 15G + NemOut® at 0.10 pound per acre (treatment four) contained higher numbers of reniform nematodes than treatments with Temik 15G (treatment two) and Avicta + NemOut® at 0.15 pound per acre (treatment seven). At harvest time, reniform populations in the treatment with Temik 15G (treatment two) were lower than populations in the control (treatment one) and Avicta (treatment three) treatments. Seed cotton yields varied by 317 pounds per acre at harvest with an average of 2804 pounds per acre of seed cotton produced over all nematicide treatments. Statistically cotton yields were similar among all the nematicides and the untreated control. COTTON RESPONSE TO NEMOUT® FOR RENIFORM NEMATODE MANAGEMENT IN SOUTH ALABAMA, 2008 Treatment 1. Control 2. Temik 15 G 3. Avicta 4. Temik 15 G NemOut 3-7 Leaf stage 5. Temik 15 G NemOut 3-7 Leaf stage 6. Avicta NemOut 3-7 Leaf stage 7. Avicta NemOut 3-7 Leaf stage LSD (P≤0.05) 1 Rate 5.00 lb/A 0.151 5.00 lb/A 0.10 lb/A 5.00 lb/A 0.15 lb/A 0.151 0.10 lb/A 0.151 0.15 lb/A Stand 34 DAP2 32.3 29.1 32.2 29.2 33.0 34.2 32.2 NS3 Vigor 34 DAP 1.8 3.2 1.7 2.2 2.8 1.8 2.2 NS ——Rotylenchulus reniformis/150 cm³—— 34 DAP 63 DAP 96 DAP 155 DAP 206 3260 ab 10133 ab 3039 a 373 1777 ab 6142 b 1095 b 425 5377 a 9824 ab 3245 a 425 1691 b 12579 a 1803 ab 451 309 322 NS 2395 ab 4836 ab 3245 ab 3650.3 9605 ab 10944 ab 6116 b 5996.1 2150 ab 1803 ab 2627 ab 1648 Yield lb/A 2790 2570 2754 2693 2804 2881 2754 NS Avicta is a seed treatment placed on the seed by the manufacturers at a rate of 0.15 mg a.i. per seed. 2 Days after planting. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 60 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF AERIS SEED TREATMENT FOR RENIFORM NEMATODE MANAGEMENT IN COTTON IN NORTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, C. H. Burmester, and B. E. Norris Experimental seed treatments were evaluated for the management of reniform nematodes in a naturally infested producer’s field near the Tennessee Valley Research and Extension Center in Belle Mina, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Decatur silty loam (24 percent sand, 49 percent silt, 28 percent clay). The seed treatments were applied to ST 4554 Flex B2 cotton seed by Bayer. Temik 15G (5 pounds per acre) was applied at planting on April 30 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with a 40-inch row spacing, and were arranged in a randomized complete block design with five replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 35, 63, 97, and 154 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in late April through harvest in early October were 71.1, 78.4, 89.3, 91.1, 88.3, and 83.3 degrees F with average minimum temperatures of 48.9, 57.3, 65.9, 67.5, 66.4, and 62.5 degrees F, respectively. Rainfall accumulation for each month was 3.6, 4.0, 2.6, 2.3, 4.8, and 0.8 inches with a total of 18.2 inches. The drought continued in 2008 but was not as severe as in 2007. Thus, reniform nematode pressure was moderate. Reniform nematode numbers at planting averaged 1500 vermiform life stages per 150 cm3 of soil at planting. Plant stand was not reduced by any nematicide application and all stands were within the optimum range of three plants per foot of row. Plant vigor was visually improved in all plots with a nematicide application as compared to the untreated control (treatment one). Reniform numbers were lower (P ≤ 0.10) at 35 days after planting in all treatments with Temik 15G (treatments four, five, six, and eight). However a lack of rainfall in June reduced nematode collection efficiency and no differences were observed between any treatments. By August all nematicide treatments except for the Aeris + Temik 15 G sidedress (treatment six) supported lower reniform numbers (P ≤  0.10) as compared to the untreated control. By harvest reniform numbers had dropped in all treatments, but the lowest numbers were observed in Abermectin + Temik 15 G combinations (treatments five and seven). Seed cotton yields varied by 595 pounds per acre at harvest with an average of 3150 pounds per acre of seed cotton produced over all nematicide treatments. The Aeris seed treatment (treatment two) and Abermectin + Temik 15G (treatment 5) produced greater yields (P ≤ 0.10) than the untreated control and the Temik 15 G treatment alone. EFFECT OF COTTON SEED TREATMENTS ON STAND, PLANT VIGOR, NEMATODE NUMBERS AND SEED COTTON YIELD Treatment 1. Untreated 2. Aeris 3. Abermectin 4. Aeris Temik 15G 5. Abermectin Temik 15G 6. Aeris Temik 15G SD3 7. Abermectin Temik 15G SD 8. Temik 15G LSD (P≤ 0.10) SD CV 1 2 Rate 0.75 mg ai/seed 500.4 mg ai/seed 0.75 mg ai/seed 5 lb/A 500.4 mg ai/seed 5 lb/A 0.75 mg ai/seed 5 lb/A 500.4 mg ai/seed 5 lb/A 5 lb/A Stand/1-ft row1 13 May 3.2 2.6 2.8 3.0 3.0 2.5 2.9 3.1 NS4 3.9 13.5 Plant vigor2 —Rotylenchulus reniformis/150cm3 soil— 4 Jun 4 Jun 2 Jul 5 Aug 6 Oct 2.3 b 3172.4 a 479.0 3043.6 a 1236.2 a 3.5 a 1668.8 ab 262.7 1776.8 b 1900.4 a 3.3 a 2070.2 ab 370.8 1776.8 b 1112.2 a 3.7 a 1437.0 b 401.7 1452.4 b 1328.6 a 3.9 a 3.7 a 3.4 a 880.8 b 1220.6 b 2209.4 ab 1143.6 b 1546.7 1437.7 83.3 247.2 309.0 216.3 432.6 NS 274.4 80.7 1375.2 b 741.8 b Seed cotton lb/A 2819 b 3299 a 3114 ab 3138 ab 3413 a 3183 ab 3037 ab 2883 b 378 381.2 11.3 2147.8 ab 1405.8 a 1761.4 b 2256.0 b 1227.8 1141.3 58.6 865.2 b 1143.2 a 767.7 713.56 58.65 3.7 a 0.6 0.5 15.5 Stand counted from 10 feet of row and averaged. Plant vigor ratings scale from 1 to 5 with 5 being the most vigorous and 1 the least. 3 Sidedress application. 4 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 61 EVALUATION OF EXPERIMENTAL SEED TREATMENT COMBINATIONS FOR RENIFORM NEMATODE MANAGEMENT IN COTTON IN NORTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, C. H. Burmester, and B. E. Norris Experimental seed treatments were evaluated for the management of reniform nematodes in a naturally infested producer’s field near the Tennessee Valley Research and Extension Center in Belle Mina, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Decatur silty loam (24 percent sand, 49 percent silt, 28 percent clay). The seed treatments were applied to DPL444BG/RR cotton seed by Syngenta. Temik 15G (5 pounds per acre) was applied at planting on April 30 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25-foot long with a 40-inch row spacing, and were arranged in a randomized complete block design with five replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 35, 63, 97, and 154 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in late April through harvest in early October were 71.1, 78.4, 89.3, 91.1, 88.3, and 83.3 degrees F with average minimum temperatures of 48.9, 57.3, 65.9, 67.5, 66.4, and 62.5 degrees F, respectively. Rainfall accumulation for each month was 3.6, 4.0, 2.6, 2.3, 4.8, and 0.8 inches with a total of 18.2 inches. The drought continued in 2008 but was not as severe as in 2007. Thus reniform nematode pressure was moderate. Reniform nematode numbers at planting averaged 1716 vermiform life stages per 150 cm3 of soil at planting. Plant stand was not affected by any nematicide application and all stands were in the optimum range of three plants per foot of row. Plant vigor was visually improved in A15436, Dynasty CST 125 FS, Cruiser 5 FS, AVICTA 4.17 FS, + A9890 (treatment six) as compared to the control A15436 + Cruiser 5 FS (treatment one). Reniform numbers were lower (P≤ 0.10) at 30 days after planting on June 4 in the combination treatment of A15436, Allegiance-FL, Baytan 30 Trilex F, STO15273, and STP17217 (treatment nine) and A15436 + Temik 15G (treatment ten). However a lack of rainfall in June reduced nematode collection efficiency and no differences were observed between any treatments. By August the combination treatment of A15436, Allegiance-FL, Baytan 30 Trilex F, STO15273, and STP17217 (treatment nine) supported higher nematode numbers than all other treatments. At harvest reniform numbers had dropped in all treatments. Seed cotton yields varied by 499 pounds per acre at harvest with an average of 3480 pounds per acre of seed cotton produced over all nematicide treatments. None of the experimental seed treatment nematicides nor the standard A15436 + Temik 15 G (treatment ten) increased yield (P ≤ 0.10) as compared to the control. Nematode numbers did not increase to levels as seen in this field in previous years probably due to the lack of rainfall in June and July. 62 ALABAMA AGRICULTURAL EXPERIMENT STATION EFFECT OF EXPERIMENTAL SEED TREATMENTS ON STAND, PLANT VIGOR, NEMATODE NUMBERS, AND SEED COTTON YIELD Treatment 1. A15436 Cruiser 5 FS 2. A15436 Cruiser 5 FS A9625 3. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS 4. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS A9625 5. A15436 Cruiser 5 FS A9890 6. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS A9890 7. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS A9890 A9625 8. Mertect 500 SC A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS 9. A15436 Allegiance –FL Baytan 30 Trilex Flowable STP15273 STP17217 10. A15436 Temik 15 G LSD (P≤ 0.10) SD CV 1 2 Stand/1-ft row1 Plant vigor2 Rate 13 May 4 Jun 31 g ai 100 kg seed 3.4 3.1 b 0.342 mg ai/seed 31 g ai 100 kg seed 3.4 3.1 b 0.342 mg ai/seed 1.0 g ai 100 kg seed 31 g ai 100 kg seed 3.7 3.5 ab 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 31 g ai 100 kg seed 3.9 3.4 ab 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 1.0 g ai 100 kg seed 31 g ai 100 kg seed 3.7 3.7 ab 0.342 mg ai/seed 40 g ai 100 kg seed 31 g ai 100 kg seed 3.4 4.1 a 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 40 g ai 100 kg seed 31 g ai 100 kg seed 3.9 3.2 b 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 40 g ai 100 kg seed 1.0 g ai/100 kg seed 20.0 g 100 kg seed 3.7 3.9 ab 31 g ai 100 kg seed 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 31 g ai 100 kg seed 3.7 3.5 ab 15.0 g 100 kg seed 5.0 g 100 kg seed 10 g ai/100 kg seed 0.375 mg ai/seed 0.375 mg ai/seed 31 g ai 100 kg seed 3.3 3.7 ab 5 lb/A NS3 0.5 0.6 0.5 1.6 13.7 —Rotylenchulus reniformis/150cm3 soil— 4 Jun 2 Jul 5 Aug 6 Oct 2441.0 a 309.0 2259.4 b 386.3 1746.0 a 2101.4 a 231.7 448.1 2225.0 b 2849.0 b Seed cotton lb/A 3513 a 3496 a 3327 b 479.0 401.7 2462.6 a 293.5 1591.4 b 401.7 3238 b 1699.6 a 1282.4 ab 401.7 401.7 2410.4 b 1884.8 b 587.1 247.2 3529 a 3590 a 2054.8 a 448.1 2518.4 b 324.5 3420 b 1653.2 a 401.7 1529.6 b 170.0 3429 b 1251.4 b 463.5 5006 a 664.35 3539 a 1050.6 b 1610.7 1589.3 87.1 185.4 NS 263.4 73.5 1730.6 b 2058.2 1932.5 80.5 463.5 NS 344.9 83.6 3737 a 264 248 7.1 Stand counted from 10 feet of row and averaged. Plant vigor ratings scale from 1 to 5 with 5 being the most vigorous and 1 the least. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 63 EVALUATION OF EXPERIMENTAL NEMATICIDE SEED TREATMENTS FOR RENIFORM NEMATODE MANAGEMENT IN COTTON IN NORTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, C. H. Burmester, and B. E. Norris Experimental seed treatment nematicides were evaluated for the management of reniform nematodes in a naturally infested producer’s field near the Tennessee Valley Research and Extension Center in Belle Mina, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Decatur silty loam (24 percent sand, 49 percent silt, 28 percent clay). The seed treatments were applied to DPL444BG/RR cotton seed by Syngenta. Temik 15G (5 pounds per acre) was applied at planting on April 30 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25-foot long with a 40-inch row spacing, and were arranged in a randomized complete block design with five replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 35, 63, 97, and 154 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in late April through harvest in early October were 71.1, 78.4, 89.3, 91.1, 88.3, and 83.3 degrees F with average minimum temperatures of 48.9, 57.3, 65.9, 67.5, 66.4, and 62.5 degrees F, respectively. Rainfall accumulation for each month was 3.6, 4.0, 2.6, 2.3, 4.8, and 0.8 inches with a total of 18.2 inches. The drought continued in 2008 but was not as severe as in 2007. Reniform nematode pressure was moderate and secondary to the lack of rainfall during bloom. Reniform nema- tode numbers at planting averaged 1716 vermiform life stages per 150 cm3 of soil at planting. Plant stand was not affected by any nematicide application as compared to the control A15436 + Cruiser 5 FS (treatment one) and all stands were in the optimum range of three plants per foot of row. Plant vigor was visually improved (P ≤ 0.10) in six of the eight seed treatments as compared to the control A15436 + Cruiser 5 FS (treatment one). The A15436, Dynasty CST 125 FS, A16115, + EXC3405 (treatment eight) appeared to suffer some phytotoxicity. Reniform numbers were lower (P ≤ 0.10) at 30 days after planting on June 4 in the combination treatment of A15436, Dynasty 100FS + A16115 (treatment five) as compared to A15436, AllegianceFL, Baytan 30 Trilex F, STO15273, and STP17217 (treatment nine) but not the control A15436 + Cruiser 5 FS (treatment one). However a lack of rainfall in June and July reduced nematode numbers below expected populations and no differences were observed between any treatments. The total reniform numbers across the season were reduced 60 percent in the A15436, Dynasty 100FS + A16115 (treatment five) as compared to the control A15436 + Cruiser 5 FS. Seed cotton yields varied by 462 pounds per acre at harvest with an average of 2031 pounds per acre of seed cotton produced over all nematicide treatments. None of the experimental seed treatment nematicides nor the standard A15436 + Temik 15 G (treatment two) increased yield (P ≤ 0.10) as compared to the control A15436 + Cruiser 5 FS (treatment one). However, A15436, Dynasty 100FS + A16115 (treatment six); A15436, A16115, Dynasty 100FS + EXC3405 (treatment seven); and A15436, Allegiance-FL, Baytan 30 Trilex F, STO15273, and STP17217 (treatment nine) increased yields (P ≤ 0.10) as compared to the A15436, Dynasty CST 125 FS, A16115, + EXC3405 (treatment eight), which had appeared to suffer some phytotoxicity early in the season. 64 ALABAMA AGRICULTURAL EXPERIMENT STATION EFFECT OF NEMATICIDE SEED TREATMENTS ON STAND, PLANT VIGOR, NEMATODE NUMBERS, AND SEED COTTON YIELD Treatment 1. A15436 Cruiser 5 FS 2. A15436 Temik 15 G 3. A15436 Dynasty 100 FS Cruiser 5 FS AVICTA 4.17 FS 4. A15436 Dynasty 100 FS A16115 5. A15436 Dynasty 100 FS A16115 6. A15436 Dynasty 100 FS A16115 7. A15436 A16115 Dynasty 100 FS EXC3405 8. A15436 Dynasty 100 FS A16115 EXC3405 9. A15436 Allegaince-LS Baytan 30 Trilex F STP15273 STP17217 LSD (P ≤ 0.10) SD CV 1 2 Stand/1-ft row1 Plant vigor2 Rate 13 May 4 Jun 31.0 g ai/100 kg 3.78 3.0 b 0.342 mg ai/seed 31.0 g ai/100 kg 3.42 3.4 a 5 lb/A 31.0 g ai/100 kg 3.84 3.6 a 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 31.0 g ai/100 kg 4.04 3.2 ab 0.034 mg ai/seed 0.5 mg ai/seed 31.0 g ai/100 kg 3.22 3.6 a 0.034 mg ai/seed 0.5 mg ai/seed 31.0 g ai/100 kg 3.60 3.5 a 0.034 mg ai/seed 0.5 mg ai/seed 31.0 g ai/100 kg 3.46 3.4 a 0.5 mg ai/seed 0.034 mg ai/seed 29.57 ml/100 kg 31.0 g ai/100 kg 3.44 2.0 c 0.034 mg ai/seed 0.5 mg ai/seed 29.57 ml/100 kg 31.0 g ai/100 kg 3.30 3.4 a 15.0 g ai/100 kg 5.0 g ai/100 kg 10.0 g ai/100 kg 0.375 mg ai/seed 0.375 mg ai/seed NS3 0.3 4.9 0.3 13.8 9.0 —Rotylenchulus reniformis/150cm3 soil— 4 Jun 2 Jul 5 Aug 6 Oct 2008.3 a 339.9 988.8 972.1 679.8 a 1514.1 a 139.1 92.7 633.8 726.0 Seed cotton lb/A 2159 1925 1854 885.8 978.5 1436.9 a 339.9 b 741.6 a 973.4 a 309.0 216.3 123.6 293.6 954.0 509.8 1128.2 1637.6 1091.8 664.4 1313.3 1339.0 2010 1970 2213 2227 1529.6 a 154.5 1313.4 1313.3 1787 2302.1 a 139.1 1498.8 1066.1 2249 1811.1 1687.5 131.8 NS 240.0 119.5 NS 1136.1 108.9 NS 832.3 77.8 NS 387.7 19.0 Stand counted from 10 feet of row and averaged. Plant vigor ratings scale from 1 to 5 with 5 being the most vigorous and 1 the least. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 65 EVALUATION OF STARTER FERTILIZER AS A MEANS FOR RENIFORM NEMATODE CONTROL IN SOUTH ALABAMA, 2008 N. S. Sekora, K. S. Lawrence, J. D. Castillo, S. R. Moore, and J. R. Akridge Evaluations were carried out at a field site in Huxford, Alabama with sandy loam soil. At the soil depth of 4 inches on May 6 (day of planting), soil temperature was 75 degrees F with adequate moisture. The manufacturer applied all fungicide seed treatments. All other treatments were applied with a chemical applicator attached to the planter. Temik 15G (5 pounds per acre) was applied in the seed furrow at planting by granular applicators attached to the planter. Plots consisted of a randomized complete block arrangement of two 25-foot rows spaced 40 inches apart. Nematode samples were taken by collecting ten soil cores (each 1 inch in diameter and 6 inches deep) randomly from the two rows of each plot. Nematodes were extracted from the soil samples by gravity sieving and sucrose centrifugation. All other production practices for herbicides, fertilizers, and insecticides were carried out as recommended by the Alabama Cooperative Extension System. Test plots were harvested on October 10. The SAS General Linear Models program was used for analysis of variance, and Fisher’s protected least significant difference (LSD) test was used for pairwise means comparisons. Average maximum temperatures for May 6 through October 10 were 87.4, 93.3, 92.8, 90.4, 88.0, and 83.9 degrees F, respectively, and average minimum temperatures were 64.8, 69.6, 71.5, 71.4, 67.3, and 59.4 degrees F, respectively. Rainfall totals for May 6 through October 10 were 2.80, 7.32, 5.04, 9.46, 1.68, and 1.61 inches, respectively. Total rainfall over the growing season was 27.9 inches. Moderate conditions were present for Rotylenchulus reniformis impact this year. At both 29 days after planting and 44 days after planting, no difference was observed in R. reniformis numbers within plots. However, differences in R. reniformis numbers were observed at both 77 days after planting and at harvest. Numbers at 77 days after planting ranged from 1236 to 8729 nematodes/150cm3 soil. Treatment one plots (nitrogen) had significantly fewer nematodes/150cm3 soil than treatment two (nitrogen phosphorus) and treatment three (worm tea of fermented worm castings) plots. Overall, all of the treatments were similar to the control at 77 days after planting. At harvest, treatment three (worm tea) had significantly lower populations of R. reniformis per 150cm3 soil than the control and both nitrogen-based treatments. The decreased populations did not impact yield, since no significant difference in yield was observed among treatments. Plot yields ranged from 2213 to 3551 pounds per acre with a mean of 2861 pounds per acre. EVALUATION OF STARTER FERTILIZER AS A MEANS FOR RENIFORM NEMATODE CONTROL IN SOUTHERN ALABAMA, 2008 Treatment 1. Nitrogen 20 lb/A 2. Nitrogen 20 lb/A Phosphorus 19 lb/A 3. Worm tea 4. Control LSD (P ≤ 0.10) 1 2 Vigor 4 Jun 3.3 3.6 3.7 3.5 NS2 1 ————Total number of nematodes/150cm3 soil ———— R. reniformis R. reniformis R. reniformis R. reniformis 4 Jun 9 Jul 11 Aug 10 Oct 185.4 1514.1 1993.0 b 3460.8 a 185.4 1081.5 4357.0 a 4171.5 a 401.7 525.3 NS 818.9 1622.3 NS 4511.6 a 3692.8 ab 2022.2 1931.3 b 3182.7 a 1102.5 Seed yield lb/A 10 Oct 2874 2837 2817 2916 NS Vigor ratings based on 1-5 scale, 1 being least vigorous and 5 being the most vigorous. NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 66 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF STARTER FERTILIZER AS A MEANS FOR RENIFORM NEMATODE CONTROL IN NORTH ALABAMA, 2008 N. S. Sekora, K. S. Lawrence, J. D. Castillo, S. R. Moore, C. H. Burmister, and B. E. Norris The field site was a sandy loam soil. The soil temperature was 70.0 degrees F with adequate moisture at a soil depth of 4 inches on April 29 (day of planting). The manufacturer applied all fungicide seed treatments and all other treatments were applied with a chemical applicator attached to the planter. Temik 15G (5 pounds per acre) was applied in the seed furrow at planting by granular applicators attached to the planter. Plots consisted of a randomized complete block arrangement of blocks with two 25-foot rows spaced 40 inches apart per plot. Nematode samples were taken by collecting ten soil cores (each 1 inch in diameter and 6 inches deep) randomly from the rows within each plot. Nematodes were extracted from the soil samples by combined gravity sieving and sucrose centrifugation. All other production practices for herbicides, fertilizers, and insecticides were carried out as recommended by the Alabama Cooperative Extension System. Test plots were harvested on September 18. The SAS General Linear Models program was used for analysis of variance, and Fisher’s protected least significant difference (LSD) test was used for pairwise treatment mean comparisons. Average monthly maximum temperatures for April 29 through October 3 were 65.0, 78.4, 89.3, 91.1, 88.3, 88.0, 78.0 degrees F, respectively, and average minimum temperatures were 38.0, 57.3, 65.9, 67.5, 66.4, 67.3, and 46.7 degrees F, respectively. Total rainfall over the growing season was 15.5 inches and monthly rainfall totals for April 29 through October 10 were 0.00, 4.00, 2.66, 2.26, 4.81, 1.68, and 0.00 inches, respectively. Growing conditions for cotton were moderate this year, but dry during the bloom period. Initial populations of Rotylenchulus reniformis at 36 days after planting were significantly lower in the treatment one (nitrogen) plots than treatment four (control), though not significantly different from treatment two (nitrogen phosphorus) or treatment three (worm tea of fermented worm castings). Populations of R. reniformis per 150cm3 soil showed no significant difference among treatments at both 65 days after planting and 96 days after planting. At harvest, treatment one (nitrogen) and treatment four (control) had significantly lower populations of R. reniformis than treatment three (worm tea). Treatment two (nitrogen phosphorus) was not significantly different from any other treatment. The population differences among treatments at harvest did not impact yield. Though no significant difference in yield was observed among treatments, plot yields ranged from 3136 to 4710 pounds per acre with a mean of 4147 pounds per acre. Differences among treatments were likely not observed due to drought conditions at the test site during the cotton bloom period. EVALUATION OF STARTER FERTILIZER AS A MEANS FOR RENIFORM NEMATODE CONTROL IN NORTH ALABAMA, 2008 Treatment 1. Nitrogen 20 lb/A 2. Nitrogen 20 lb/A Phosphorus 19 lb/A 3. Worm tea 4. Control LSD (P ≤ 0.10) 1 Stand/25-ft row 13 May 55.6 48.4 53.8 50.2 NS1 ————Total number of nematodes/150cm3 soil———— R. reniformis R. reniformis R. reniformis R. reniformis 4 Jun 3 Jul 5 Aug 6 Oct 324.6 b 185.4 1483.2 216.3 b 880.6 ab 160.0 1143.3 339.9 ab 648.8 ab 1143.2 a 585.8 216.3 200.9 NS 2024.0 1606.8 NS 664.4 a 170.0 b 440.4 Seed yield lb/A 3 Oct 4052 4120 4226 4191 NS NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 2008 AU CROPS: COTTON RESEARCH REPORT 67 EVALUATION OF AERIS SEED TREATMENT AND GRANULAR NEMATICIDES FOR RENIFORM NEMATODE MANAGEMENT IN SOUTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, J. D. Castillo, N. S. Sekora, and J. R. Akridge Experimental seed treatments were evaluated for the management of reniform nematodes in a naturally infested producer’s field near Huxford, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Ruston very fine sandy loam (59 percent sand, 33 percent silt, 8 percent clay). The seed treatments were applied to ST 4554 Flex B2 cotton seed by Bayer Crop Science. Temik 15G (5 pounds per acre) was applied at planting on May 6 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with 3-foot row spacing, and were arranged in a randomized complete block design with six replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 30, 63, 96, and 155 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤  0.10). Monthly average maximum temperatures from planting in early May through harvest in early October were 86.5, 93.3, 92.8, 90.4, and 88.8 degrees F with average minimum temperatures of 63.6, 69.6, 71.5, 71.4, and 67.3 degrees F, respectively. Rainfall accumulation for each month was 3.6, 7.3, 5.0, 9.5, and 1.7 inches with a total of 27 inches. The drought continued in 2008 but was not as severe as in 2007. Thus, reniform nematode pressure was moderate. Reniform nematode numbers at planting averaged 47 vermiform life stages per 150 cm3 of soil at planting, which is low, but the soil moisture was 6.0 percent. Plant stand was greater in Aeris + Temik 15 G (treatment four) and Abermectin + Temik 15 G (treatment five) as compared to Abermectin alone (treatment three) but not from the control (treatment one) and all stands were within the optimum of three plants per foot of row. Plant vigor was visually improved in these same seed treatments + Temik 15 G combinations as compared to the control (treatment one). Reniform numbers were similar between all treatments at 30 days after planting, although only 3.6 inches of rain had been recorded during this month. By July the seed treatment + Temik 15 G combination treatments (treatments four, five, six, and seven) supported 56 percent fewer reniform as compared to the untreated control; however, these reduced numbers were not significant. At mid-season, August 11, the combination seed treatment + Temik 15 G continued to support fewer reniform (P ≤ 0.10) as compared to the control. By harvest reniform numbers had dropped in all treatments except for Abermectin + Temik 15 G SD (treatment seven). Seed cotton yields varied by 530 pounds per acre at harvest with an average of 2973 pounds per acre of seed cotton produced over all nematicide treatments. EFFECT OF NEMATICIDE SEED TREATMENTS ON STAND, PLANT VIGOR, NEMATODE NUMBERS, AND SEED COTTON YIELD Treatment 1. Untreated 2. Aeris 3. Abermectin 4. Aeris Temik 15G 5. Abermectin Temik 15G 6. Aeris Temik 15G SD3 7. Abermectin Temik 15G SD 8. Temik 15G LSD (P≤ 0.10) SD CV 1 2 Stand/1-ft row1 Plant vigor2 —Rotylenchulus reniformis/150cm3 soil— 6 Jun 4 Jun 6 Jun 9 Jul 11 Aug 11 Oct 3.9 ab 3.3 b 283.3 3660.8 8819.4 a 4184.4 b 0.75 mg ai/seed 4.1 ab 3.5 b 206.0 3575.0 6295.9 a 3643.6 b 500.4 mg ai/seed 3.2 b 3.4 b 154.5 3029.9 8175.6 a 4287.4 b 0.75 mg ai/seed 4.5 a 4.0 a 180.3 1763.9 6115.6 b 3695.1 b 5 lb/A 500.4 mg ai/seed 4.2 a 3.8 a 399.1 1137.3 5832.4 b 3128.6 b 5 lb/A 0.75 mg ai/seed 3.9 ab 3.7 a 218.9 1802.5 6759.4 a 3759.5 b 5 lb/A 500.4 mg ai/seed 3.8 ab 3.6 ab 218.9 1708.1 8252.9 a 8046.9 a 5 lb/A 5 lb/A 4.1 ab 3.3 b 141.6 2503.1 9707.8 a 3115.8 b 0.9 0.3 NS4 NS 3564.6 2001.0 9.0 0.4 228.9 2562.9 3638.2 2042.3 22.5 10.2 101.6 106.9 48.5 48.3 Rate Seed cotton lb/A 2994 ab 2998 ab 3180 a 2650 b 2912 ab 3101 a 3135 a 2817 ab 422 430 14.49 Stand counted from 10 feet of row and averaged. Plant vigor ratings scale from 1 to 5 with 5 being the most vigorous and 1 the least. 3 Sidedress application of the granule at pin head square growth stage. 4 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 68 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF EXPERIMENTAL BIOLOGICAL NEMATICIDE SEED TREATMENTS FOR RENIFORM NEMATODE MANAGEMENT IN COTTON IN SOUTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, J. D. Castillo, N. S. Sekora, and J. R. Akridge Experimental seed treatments were evaluated for the management of reniform nematodes in a naturally infested producer’s field near Huxford, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Ruston very fine sandy loam (59 percent sand, 33 percent silt, 8 percent clay). The seed treatments were applied to DPL555BG/RR cotton seed by Bayer Crop Science. Temik 15G (5 pounds per acre) was applied at planting on May 6 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with 3-foot row spacing, and were arranged in a randomized complete block design with six replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 30, 63, 96, and 155 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in early May through harvest in early October were 86.5, 93.3, 92.8, 90.4, and 88.8 degrees F with average minimum temperatures of 63.6, 69.6, 71.5, 71.4, and 67.3 degrees F, respectively. Rainfall accumulation for each month was 3.6, 7.3, 5.0, 9.5, and 1.7 inches with a total of 27 inches. The drought continued in 2008 but was not as severe as in 2007. Reniform nematode pressure was moderate and secondary to the lack of rainfall during bloom. Reniform nematode numbers at planting averaged 56 vermiform life stages per 150 cm3 of soil at planting. Plant stand was similar between all experimental seed treatments with cotton plant stands in the optimum range of three plants per foot of row. The skip index, indicating stand uniformity, was higher in the Baytan 30 + Vortex FL + Allegiance FL + Aeris seed applied system (treatment four) as compared to the Baytan 30 + Vortex FL + Allegiance FL + Gaucho Grande (treatment one) industry standard. Reniform numbers were higher (P ≤ 0.10) in the Baytan 30 + Vortex FL + Allegiance FL + Aeris (treatment three) combination as compared to the Baytan 30 + Vortex FL + Allegiance FL + Gaucho Grande (treatment one) industry standard control at 30 days after planting. However, by 63 days after planting, no differences in nematode numbers were observed between any treatments. At midseason, nematode numbers increased in the Baytan 30 + Vortex FL + Allegiance FL + Crusier 600FS +Avicta 500FS (treatment eight) as compared to Baytan 30 + Vortex FL + Allegiance FL + Aeris (treatment three) combination and the Baytan 30 + Vortex FL + Allegiance FL +Aeris + with Bacillus firmus (treatment four). By harvest, the seed treatment combination Baytan 30 + Vortex FL + Allegiance FL + test compound 1 (treatment six) held nematode numbers below that in the Baytan 30 + Vortex FL + Allegiance FL + Aeris treatment (treatment three). Seed cotton yields varied by 173 pounds per acre at harvest with an average of 2752 pounds per acre of seed cotton produced over all nematicide treatments. None of the experimental seed treatment nematicides increased yield (P ≤ 0.10) as compared to the control. The lack of rainfall during the bloom period caused plant stress and probably reduced yield differences due to the nematode. 2008 AU CROPS: COTTON RESEARCH REPORT 69 SEED TREATMENT EFFECTS ON COTTON STAND, SKIP INDEX, NEMATODE NUMBERS, AND SEED COTTON YIELD Treatment 1. Baytan 30 Vortex FL Allegiance FL Gaucho Grande 2. Baytan 30 Vortex FL Allegiance FL Aeris 3. Baytan 30 Vortex FL Allegiance FL Aeris Bacillus firmus tech 4. Baytan 30 Vortex FL Allegiance FL Aeris Bacillus firmus tech 5. Baytan 30 Vortex FL Allegiance FL Aeris Bacillus firmus tech 6. Baytan 30 Vortex FL Allegiance FL Test compound 1 7. Baytan 30 Vortex FL Allegiance FL Gaucho Grande Bacillus firmus tech 8. Baytan 30 Vortex FL Allegiance FL Crusier 600FS Avicta 500FS LSD (P=0.10) Standard Deviation CV 1 2 Rate 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.375 mg ai/seed 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.75 mg ai/seed 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.75 mg ai/seed 1.0 g/100 kg 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.75 mg ai/seed 1.0 g/100 kg 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.75 mg ai/seed 1.0 g/100 kg 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 1.0 g/100 kg 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.375 mg ai/seed 1.0 g/100 kg 32.5 ml/100 kg 2.5 g ai/100 kg 15.6 g ai/100 kg 0.34 mg ai/seed 0.15 mg ai/seed Stand/ 1-ft row1 4 Jun 3.4 Skip index2 —Rotylenchulus reniformis/150cm3 soil— 4 Jun 4 Jun 7 Jul 11 Aug 6 Oct 0.2 b 154.5 1686.8 5716.7 ab 1648.0 b Seed cotton lb/A 2736 3.1 0.3 b 193.1 2343.3 6399.0 ab 2884.0 ab 2732 3.3 0.3 b 450.6 1802.8 4532.2 b 3437.6 a 2726 2.9 2.0 a 154.5 1970.0 4673.7 b 2652.3 ab 2663 2.8 1.0 ab 193.1 2111.7 5703.7 ab 2343.3 ab 2782 3.0 1.5ab 218.9 2279.0 5111.7ab 1828.3b 2836 3.0 0.8ab 257.5 1725.7 6025.7ab 2420.5ab 2735 2.9 0.8 ab 244.6 2369.2 7081.2 a 2188.8 ab 2795 NS3 0.8 2.6 1.5 1.6 176.7 NS 195.2 83.7 NS 1540.1 75.6 2348.5 2397.0 42.4 1382.3 1410.8 58.2 NS 239.3 8.7 Stand counted from 10 feet of row and averaged. Skip index is a measure of uniformity of the stand across the row. The higher the number, the more space between plants with 1 = 1 foot of empty row and 25 = 25 feet of row. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 70 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF COTTON SEED TREATMENT AND GRANULAR NEMATICIDES FOR RENIFORM NEMATODE MANAGEMENT IN SOUTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, J. D. Castillo, N. S. Sekora, and J. R. Akridge Experimental seed treatments were evaluated for the management of reniform nematodes in a naturally infested producer’s field near Huxford, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Ruston very fine sandy loam (59 percent sand, 33 percent silt, 8 percent clay). The seed treatments were applied to DPL555BG/RR cotton seed by Syngenta. Temik 15G (5 pounds per acre) was applied at planting on May 6 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with a 3-foot row spacing ,and were arranged in a randomized complete block design with six replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 30, 63, 96, and 155 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in early May through harvest in early October were 86.5, 93.3, 92.8, 90.4, and 88.8 degrees F with average minimum temperatures of 63.6, 69.6, 71.5, 71.4, and 67.3 degrees F, respectively. Rainfall accumulation for each month was 3.6, 7.3, 5.0, 9.5, and 1.7 inches with a total of 27 inches. The drought continued in 2008 but was not as severe as in 2007. Thus reniform nematode pressure was moderate. Reniform nematode numbers at planting averaged 52 vermiform life stages per 150 cm3 of soil at planting. Plant stand was similar (P≤ 0.10) to the control A15436 + Cruiser 5 FS (treatment one) in all treatments except for A15436 + Temik 15G (treatment ten). The A15436 + Temik 15G (treatment ten) seed treatment plus granular nematicide produced a stand of less than the optimum three plants per foot of row. The skip index was greater in the A15436 + Temik 15G (treatment ten) and A15436, Allegiance FL, Bayan 30, Trilex F, STP 15273, and STP 17217 (treatment nine) as compared to the control A15436 + Cruiser 5 FS (treatment one). Reniform numbers were lower than expected at 30 days after planting on June 4 due to the dry weather. None of the nematicide combinations reduced nematode numbers as compared to the control A15436 + Cruiser 5 FS (treatment one). Reniform numbers increased in July with all nematicde treatments supporting lower populations (P ≤ 0.10) than A15436 + Cruiser 5 FS (treatment one), the control. By mid-season on August 11 and at harvest on October 6, nematode numbers had increased in all treatments and no differences were found between any treatments. At harvest, reniform numbers had dropped in all treatments. Seed cotton yields varied by 723 pounds per acre at harvest with an average of 2626 pounds per acre of seed cotton produced over all nematicide treatments. All of the experimental seed treatment nematicides yielded similarly to the control A15436 + Cruiser 5 FS; however, the standard A15436 + Temik 15 G (treatment ten) produced lower yields (P ≤ 0.10) than all other seed treatments. 2008 AU CROPS: COTTON RESEARCH REPORT 71 SEED TREATMENT EFFECTS ON COTTON STAND, SKIP INDEX, NEMATODE NUMBERS, AND SEED COTTON YIELD Treatment 1. A15436 Cruiser 5 FS 2. A15436 Cruiser 5 FS A9625 3. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS 4. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS A9625 5. A15436 Cruiser 5 FS A9890 6. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS A9890 7. A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS A9890 A9625 8. Mertect 500 SC A15436 Dynasty CST 125 FS Cruiser 5 FS AVICTA 4.17 FS 9. A15436 Allegiance –FL Baytan 30 Trilex Flowable STP15273 STP17217 10. A15436 Temik 15 G LSD (P≤ 0.10) SD CV 1 2 Stand/ 1-ft row1 Rate 4 Jun 31 g ai 100 kg seed 3.4 a 0.342 mg ai/seed 31 g ai 100 kg seed 3.0 ab 0.342 mg ai/seed 1.0 g ai 100 kg seed 31 g ai 100 kg seed 3.2 a 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 31 g ai 100 kg seed 3.4 a 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 1.0 g ai 100 kg seed 31 g ai 100 kg seed 3.4 a 0.342 mg ai/seed 40 g ai 100 kg seed 31 g ai 100 kg seed 3.1 a 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 40 g ai 100 kg seed 31 g ai 100 kg seed 3.2 a 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 40 g ai 100 kg seed 1.0 g ai/100 kg seed 20.0 g 100 kg seed 3.4 a 31 g ai 100 kg seed 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 31 g ai 100 kg seed 3.3 a 15.0 g 100 kg seed 5.0 g 100 kg seed 10 g ai/100 kg seed 0.375 mg ai/seed 0.375 mg ai/seed 31 g ai 100 kg seed 2.2 b 5 lb/A 0.9 0.9 2.9 Skip index2 —Rotylenchulus reniformis/150cm3 soil— 4 Jun 4 Jun 7 Jul 11 Aug 6 Oct 1.7 b 154.5 ab 2858.5 a 4828.2 2072.9 2.5 ab 3.0 ab 115.9 b 257.5 a 1261.8 b 1326.5 b 4390.5 3785.3 1673.8 2111.5 Seed cotton lb/A 2400 a 2655 a 2603 a 2.5 ab 193.1 ab 1532.3 b 4570.8 1982.8 2682 a 1.8 b 2.5 ab 90.1 b 115.9 b 1030.2 b 1313.3 b 4635.3 4686.5 2034.3 1326.1 2814 a 2671 a 2.0 b 283.3 a 1828.5 a 3605.0 2394.8 2658 a 1.3 b 167.4 ab 927.2 b 4351.8 1841.1 2663 a 3.2 a 154.5 ab 1879.8 b 4313.2 2678.0 2787 a 3.8 a 1.7 1.7 7.2 257.5 a 135.3 139.2 77.8 2008.8 a 1219.8 1254.6 78.6 3746.7 NS3 1925.5 44.9 1532.1 NS 1402.6 71.4 2091 b 443 455.9 17.5 Stand counted from 10 feet of row and averaged. Skip index is a measure of uniformity of the stand across the row. The higher the number, the more space between planst with 1 = 1 foot of empty row and 25 = 25 feet of row. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 72 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF EXPERIMENTAL NEMATICIDE SEED TREATMENTS FOR RENIFORM NEMATODE MANAGEMENT IN COTTON IN SOUTH ALABAMA, 2008 K. S. Lawrence, S. R. Moore, J. D. Castillo, N. S. Sekora, and J. R. Akridge Experimental seed treatments were evaluated for the management of reniform nematodes in a naturally infested producer’s field near Huxford, Alabama. The field has a history of reniform nematode infestation, and the soil type is a Ruston very fine sandy loam (59 percent sand, 33 percent silt, 8 percent clay). The seed treatments were applied to DPL555BG/RR seed by Syngenta. Temik 15G (5 pounds per acre) was applied at planting on May 6 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with a 3-foot row spacing, and were arranged in a randomized complete block design with six replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined at 30, 63, 96, and 155 days after planting. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 3. Data were statistically analyzed by GLM and means compared using Fisher’s protected least significant difference test (P ≤  0.10). Monthly average maximum temperatures from planting in early May through harvest in early October were 86.5, 93.3, 92.8, 90.4, and 88.8 degrees F with average minimum temperatures of 63.6, 69.6, 71.5, 71.4, and 67.3 degrees F, respectively. Rainfall accumulation for each month was 3.6, 7.3, 5.0, 9.5, and 1.7 inches with a total of 27.1 inches. The drought continued in 2008 but was not as severe as in 2007. Reniform nematode pressure was moderate and secondary to the lack of rainfall during bloom. Reniform nematode numbers at planting averaged 56 vermiform life stages per 150 cm3 of soil at planting. Plant stand was similar between all experimental seed treatments and the control A15436 + Cruiser 5 FS (treatment one); however the industry standard A15436 + Temik 15 G (treatment two) did have a lower stand (P ≤ 0.10) as compared to the control A15436 + Cruiser 5 FS (treatment one). The skip index was also lower in the industry standard A15436 + Temik 15 G (treatment two) as compared to the control A15436 + Cruiser 5 FS (treatment one). Reniform numbers were uniform across all treatments at 30 days after planting on June 4. By July 9, however, the A15436 + Dynasty CST + A16115 (treatment five) supported fewer reniform (P ≤ 0.10) than the control A15436 + Cruiser 5 FS (treatment one) although the numbers were not lower than the A15436 + Temik 15 G (treatment two) standard. No differences in nematode numbers were observed at mid-season or at harvest on August 11 and October 6, respectively. The total reniform numbers across the season were reduced by an average of 20 percent over all experimental seed treatments as compared to the control. Seed cotton yields varied by 323 pounds per acre at harvest with an average of 2942 pounds per acre of seed cotton produced over all nematicide treatments. None of the experimental seed treatment nematicides nor the standard A15436 + Temik 15 G (treatment two) increased yield (P ≤ 0.10) as compared to the control A15436 + Cruiser 5 FS (treatment one). The lack of rainfall during the bloom period caused plant stress and probably reduced yield differences due to the nematode. 2008 AU CROPS: COTTON RESEARCH REPORT 73 SEED TREATMENT EFFECTS ON COTTON STAND, SKIP INDEX, NEMATODE NUMBERS, AND SEED COTTON YIELD Treatment 1. A15436 Cruiser 5 FS 2. A15436 Temik 15 G 3. A15436 Dynasty 100 FS Cruiser 5 FS AVICTA 4.17 FS 4. A15436 Dynasty 100 FS A16115 5. A15436 Dynasty 100 FS A16115 6. A15436 Dynasty 100 FS A16115 7. A15436 A16115 Dynasty 100 FS EXC3405 8. A15436 Dynasty 100 FS A16115 EXC3405 9. A15436 Allegaince-LS Baytan 30 Trilex F STP15273 STP17217 LSD (P ≤ 0.10) SD CV 1 2 Stand/1-ft row1 Rate 4 Jun 31.0 g ai/100 kg 4.0 ab 0.342 mg ai/seed 31.0 g ai/100 kg 2.9 c 5 lb/A 31.0 g ai/100 kg 3.9 abc 0.034 mg ai/seed 0.342 mg ai/seed 0.145 mg ai/seed 31.0 g ai/100 kg 3.6 abc 0.034 mg ai/seed 0.5 mg ai/seed 31.0 g ai/100 kg 4.2 a 0.034 mg ai/seed 0.5 mg ai/seed 31.0 g ai/100 kg 3.5 abc 0.034 mg ai/seed 0.5 mg ai/seed 31.0 g ai/100 kg 3.2 abc 0.5 mg ai/seed 0.034 mg ai/seed 29.57 ml/100 kg 31.0 g ai/100 kg 3.5 abc 0.034 mg ai/seed 0.5 mg ai/seed 29.57 ml/100 kg 31.0 g ai/100 kg 2.9 bc 15.0 g ai/100 kg 5.0 g ai/100 kg 10.0 g ai/100 kg 0.375 mg ai/seed 0.375 mg ai/seed 0.7 0.7 1.92 Skip index2 —Rotylenchulus reniformis/150cm3 soil— 4 Jun 4 Jun 7 Jul 11 Aug 6 Oct 0.7 b 167.4 1945.8 4995.5 2987.0 2.8 a 1.3 b 321.9 296.1 1287.7 1855.2 4030.0 4686.8 Seed cotton lb/A 2992 2829 2961 3154.4 2935.5 1.7 ab 0.5 b 1.7 ab 1.5 ab 334.8 167.4 141.6 334.8 1879.8 850.0 1660.8 2047.0 3875.7 4377.7 5047.2 3862.5 3102.9 3205.9 2330.4 2533.8 3024 2958 2918 3011 0.8 b 206.0 1815.5 4583.3 3579.3 2701 1.7 ab 283.3 1120.3 3849.8 3296.0 3008 1.3 1.3 94.9 NS3 209.2 83.6 NS 964.6 60.0 NS 1708.5 39.1 NS 1518.0 50.4 NS 347.5 10.5 Stand counted from 10 feet of row and averaged. Skip index is a measure of uniformity of the stand across the row. The higher the number, the more space between planst with 1 = 1 foot of empty row and 25 = 25 feet of row. 3 NS indicates that there was no significant difference (P≤ 0.10). Means within columns followed by different letters are significantly different according to Fisher’s LSD (P ≤ 0.10). 74 ALABAMA AGRICULTURAL EXPERIMENT STATION COTTON CULTIVAR RESPONSE TO ROOT-KNOT NEMATODES IN TWO TILLAGE REGIMES, 2008 K. S. Lawrence, S. R. Moore, K. S. Balkcom, and B. Durbin Six cotton cultivars were evaluated for yield response to the root-knot nematode in a naturally infested field at E. V. Smith Research and Extension Center, near Shorter, Alabama. The field had a long history of root-knot nematode infestation, and the soil type was classified as a sandy loam. Plots consisted of four rows, 50 feet long with 36-inch row spacing, and were planted in a factorial arrangement with five replications. Convention tillage and no tillage were the main factors and cotton cultivar was the sub factor with plots split with and without nematicide. Avicta amd Cruiser was applied to the seed by the manufacturer. Temik 15G (5 pounds per acre) was applied at planting on May 23 in the seed furrow with chemical granular applicators attached to the planter. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the root knot nematodes were determined at mid-seasons after a significant rainfall event. Ten soil cores, 1 inch in diameter and 6 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plant height and nodes per plant were also recorded at this time. Plots were harvested on October 22. Data were statistically analyzed by GLM and means com- pared using Fisher’s protected least significant difference test (P ≤ 0.10). Monthly average maximum temperatures for May through September were 84.5, 93.6, 92.5, 89.7, and 86.7 degrees F with average minimum temperatures of 60.9, 68.2, 70.0, 71.1, and 66.0 degrees F, respectively. Rainfall accumulation for each month was 2.52, 1.98, 4.97, 9.92, and 0.73 inches with a total of 20.1 inches. Rainfall was a limiting factor in the 2008 season; thus, rootknot nematode pressure was moderate under these conditions. Only 20 inches of rain were recorded for the entire growing season. At planting, root-knot nematode numbers averaged 51 J2’s per 150 cm3 of soil. Interactions between cultivar, tillage, and nematicide were observed for plant height and nodes per plant. Root-knot numbers of J2 from the soil varied between varieties with the lowest numbers observed in DPL 117, STM, and ST 5599. Over all cultivars, no tillage plots contained higher numbers of root-knot nematodes than conventionally tilled plots. Nematicide application did not consistently reduce rootknot numbers across cultivars. Seed cotton yields averaged 3708 pounds per acre across all cultivars with ST 5599 and STM producing a greater yield (P ≤ 0.01) than DPL 555, DPL 515, DPL 117, and DPL 143. Nematicide and tillage did not affect seed cotton yields (P ≤ 0.01). COTTON CULTIVAR RESPONSE TO ROOT-KNOT NEMATODES IN TWO TILLAGE REGIMES, 2008 Plant height in 39.7 42.3 40.4 44.6 33.7 37.7 38.1 44.2 40.5 41.1 40.7 46.2 43.0 44.5 41.5 46.6 39.3 39.3 37.1 40.6 35.7 37.0 37.5 37.7 3.4 Nodes/plant no. 19.3 17.8 18.3 19.3 15.5 16.5 17.8 19.5 18.8 18.8 20.3 21.0 20.0 19.0 19.8 21.3 16.8 18.0 16.0 17.5 18.0 18.0 18.0 18.0 1.1 Meloidogyne incognita J2 14 Aug N2 115.9 115.9 579.4 424.9 115.9 231.8 1332.6 927.0 193.1 173.8 695.3 598.7 193.1 637.3 984.9 1100.8 193.1 212.4 560.1 521.4 173.8 115.9 309.0 482.8 729.9 Seed cotton 16 Oct lb/A 3535 3694 3631 3631 3502 3913 3643 3790 3655 3603 3433 3577 3415 3522 3548 3662 3836 3906 3981 4075 3812 3777 3935 3935 443 Variety DPL 117 DPL 117 DPL 117 DPL 117 DP143 DP143 DP143 DP143 DP515 DP515 DP515 DP515 DP555 DP555 DP555 DP555 ST5599 ST5599 ST5599 ST5599 STM STM STM STM LSD (P ≤ 0.10) 1 2 Tillage1 Conv Conv No-till No-till Conv Conv No-till No-till Conv Conv No-till No-till Conv Conv No-till No-till Conv Conv No-till No-till Conv Conv No-till No-till Nematicide Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Avicta+Temik Cruiser Conv is conventional tillage; No-till is for plots with reduced tillage. N is the application of the nematicides Avicta and Temik 15 G. CONTRIBUTORS INDEX Author A. Abdelgadir J. R. Akridge F. J. Arriaga K. S. Balkcom J. Bergtold W. C. Birdsong K. L. Bowen C. Brodbeck Pages 27,28 59,65,67,68-69,70-71,72-73 13-15,17-19 13-15,17-19,22-23,24,34,74 17-19 7,58 25-26 21,29-30 S. Nightengale B. E. Norris S. H. Norwood B. Ortiz P. L. Mask B. Meyer C. C. Mitchell C. D. Monks S. R. Moore Author K. S. Lawrence Pages 12,25-26,45,46-47,48-50,51,52-53,54,55,56, 57,59,60,61-62,63-64,65,66,67,68-69, 70-71,72-73,74 21 12 22-23,24,31-33,34 7,9-11,16,17-19,25-26,27,28,42,43-44,58 45,46-47,48-50,51,52-53,54,55,56,57,59,60, 61-62,63-64,65,66,67,68-69,70-71,72-73,74 46-47,57 27,28,45,60,61-62,63-64,66 20,21,29-30 21 C. H. Burmester 7,9-11,12,21,27,28,29-30,34,45,57,60,61-62, 63-64,66 H. L. Campbell J. D. Castillo J. Clary L. M. Curtis D. P. Delaney B. Dillard M. P. Dougherty B. Durbin J. P. Fulton W. S. Gazaway 25-26 46-47,57,59,65,66,67,68-69,70-71,72-73 58 27,28,29-30 22-23,24,25-26,58 58 27,28,29-30 29-30,74 20,21,27,28,29-30 45 M. G. Patterson 41,42,43-44 M. Pegues R. Petcher A. J. Price R. L. Raper T. Reed N. S. Sekora E. Schavey E. Schwab J. N. Shaw N. Silvey R. H. Smith D. B. Weaver A. Winstead R. P. Yates 16 16 13-15,43-44 13-15,17-19,29-30 9-11,35 46-47,57,65,66,67,68-69,70-71,72-73 12 13-15 21,29-30 12 36,37,38,39,40 8 20,21,29-30 31-33 R. W. Goodman 7,16,25-26 A. K. Hagan M. H. Hall T. Harbuck D. H. Harkins J. Holliman G. Huluka J. Jones T. S. Kornecki L. Kuykendall 25-26 21 20 27,28,29-30 31-33 31-33 16 13-15 58 G. W. Lawrence 45