cc coo J= CD 74A. ca I:Ok. coi cc G2 cc 0-4 cn Ww .. ... C.2 0 cc cc C4 c; G3 A4. cn CD ca 10 CA w CONTENTS Contributors VARIETY TRIALS Cherokee County Cotton Variety Trial ..................................................................................... ............................................... 1 Evaluation of Transgenic Cotton Varieties in Ultra-narrow Row and No-till Planting Systems ............................................. 1 Variety Evaluation in Ultra-narrow Row Cotton at E. V. Smith and Prattville ....................................................................... 2 CROP PRODUCTION Evaluation of Roundup Ready Cotton in Ultra-narrow Row Systems .................................................................................... 3 Cover Crops and Tillage Methods for Ultra-narrow Row and Wide Row Cotton...................................................................4 Growth Regulator Effects on Cotton ...................................................................................... ................................................. 4 Effects of Boron and Mepiquat Chloride Timing on Irrigated Cotton Growth and Yield ....................................................... 5 Effects of Dim ilin and Boron on Cotton .................................................................................... .............................................. 6 Cotton Response to Phosphorus in Alabama's Long-term Experiments ................................................................................. 7 Nitrogen Rates for Cotton in Alabama's Long-term Experiments ...................................... ............................................. 9 Potassium Nutrition of Cotton on Long-term Experiments ................................................................. ................................ 11 Summary of 1999 Roundup Ready Cotton Produced Under Irrigated and Nonirrigated Conditions in N orth A labam a ................................................................................................................................................................ 13 INSECTICIDE APPLICATIONS Comparison of Selected In-furrow Treatments for Thrips Control in Cotton ....................................................................... 14 Evaluation of Selected Seed Treatments and In-furrow and Foliar-applied Insecticides for Thrips Control in Cotton ............................................................................................... ......................................... 15 Evaluation of Orthene, Temik, and Admire for Thrips Control in Cotton ............................................................................ 16 The Effect of Selected Insecticides on the Tarnished Plant Bug and Beneficial Arthropods in D P 20B Cotton in N orth A labam a .................................................................................................................................. 18 The Effect of Selected Insecticides on the Tarnished Plant Bug and Beneficial Arthropods in Sure-Grow 125BR Cotton in North Alabam a ................................................................................................................. 19 The Effect of Selected Insecticides on the Tarnished Plant Bug and Beneficial Arthropods in Sure-Grow 180 Cotton in Central A labam a .................................................................................................................... 21 Efficacy of Selected Insecticides for Bollworm/Budworm Control in Cotton ............................................................................ 24 Resistance Monitoring of Tobacco Budworm/Cotton Bollworm in Bt Cotton ........................................................................... 25 Evaluation of Selected Insecticides for Efficacy on Soybean Loopers ....................................................................................... 25 HERBICIDE APPLICATIONS On-farm Comparison of Cotton Weed Control in Roundup Ready Cotton ............................................................................... 27 Harvest Aid Evaluation for Cotton Regrowth Control ................................................................................................................. 27 Valor 50 W DG for Layby W eed Control in Cotton......................................................................................................................28 NEMATICIDE APPLICATIONS Impact of Various Crop Rotations and Winter Cover Crops on Reniform Nematode in Cotton......................29 Effect of Fall and Spring Telone Fumigation on the Management of Reniform Nematodes in Cotton .................................... 31 CONTENTS, CONTINUED FUNGICIDE APPLICATIONS Evaluation of Selected Experimental Seed Treatments for Control of Seedling Disease of Cotton ............................. 32 Evaluation of Selected Seed Treatments for Control of Seedling Disease of Cotton ........................................................... 33 Evaluation of In-furrow Fungicide Treatments and Fungicide Biologicals for Control of Seedling D isease of Cotton .......................................................................................................................................... 34 Evaluation of Selected In-furrow Fungicides and Fungicide Biological Combinations for Control of Seedling D isease of Cotton ............................................................................................. ........................................ 36 Evaluation of Terraclor and Rovral for Control of Seedling Disease of Cotton in Central Alabama.............................. 37 Evaluation of Terraclor and Rovral for Control of Seedling Disease of Cotton in North Alabama .............................. 38 Evaluation of Quadris for Control of Seedling Disease of Cotton in South Alabama ........................................................... 39 Evaluation of Quadris for Control of Seedling Disease of Cotton in Central Alabama...... ........ ........................... 40 Evaluation of Quadris for Control of Seedling Disease of Cotton in North Alabama ........................................................... 41 Evaluation of Selected Fungicides for Control of Cotton Boll Rot Disease on Deltapine NuCotn 33B ........................... 42 Evaluation of Selected Fungicides for Control of Cotton Boll Rot Disease on Paymaster 1220BG/RR..................................43 DEFOLIANT APPLICATIONS Evaluation of Flair as a Cotton Defoliant ............................................................... ..... . ....... 44 Evaluation of Ginstar as a Cotton Defoliant .................................................................................. 45 MOLECULAR STUDIES Evolutionary Diversity of Cellulose Synthase (CesA) in Gossypium .................................................... 46 Induction of Highly Embryogenic Calli and Plant Regeneration in Diploid and Tetraploid Cottons ............................ 46 A uthors' Index ............................................................................ .............................................................................................. 47 This publication is a joint contribution ofAuburn University, the Alabama Agricultural Experiment Station, Alabama A&M University, and the USDA Agricultural Research Service. Information contained herein is available to all persons regardless of race, color, sex, or national origin. NOTE: 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. ACKNOWLEDGMENTS: Research contained herein was partially funded through the Alabama Cotton Commission and private industry grants. All donations funding these projects, including the Alabama Cotton Commission and private industry grants, are appreciated. EDITORS Kathy S. McLean Assistant Professor Entomology and Plant Pathology Auburn University C. Dale Monks Associate Professor and Extension Specialist Agronomy and Soils Auburn University CONTRIBUTORS James R. Akridge Superintendent Monroeville Research Field Brewton Research Field Jim Bannon Interim Associate Director Alabama Agricultural Experiment Station U. R. Bishnoi Professor, Plant and Soil Science Alabama A & M University Charles Burmester Assistant Superintendent Tennessee Valley Research and Extension Center Belle Mina, AL Ellis Burgess Assoc. Superintendent Tennessee Valley Research and Extension Center Belle Mina, AL E. Cebert Plant and Soil Science Alabama A & M Univerisity Charles Cole Texas A&M University College Station, TX Richard L. Davis Consulting Entomologist, Davis Consulting Montgomery, AL Dennis P. Delaney Extension Associate, Agronomy and Soils Auburn University Deborah Delmer Professor and Chair, Section of Plant Biology University of California-Davis David Derrick County Agent, Cherokee County Alabama Cooperative Extension System B. Durbin Superintendent Agricultural Research Services Tallassee, AL Barry L. Freeman Extension Entomologist Entomology and Plant Pathology Auburn University Brian Gamble Assistant Superintendent Wiregrass Research and Extension Center Headland, AL William S. Gazaway Professor and Extension Specialist, Emeritus Entomology and Plant Pathology Auburn University Aaron Jeffries Alabama A&M University Johnie Jenkins Genetics Research Leader USDA/ARS/CSRL Mississippi State University Mehmet Karaca USDA/ARS/CSRL Mississippi State University Ronnie McDaniel Superintendent Gulf Coast Research and Extension Center Fairhope, AL Kathy S. McLean Assistant Professor, Entomology and Plant Pathology Auburn University Charles C. Mitchell Extension Agronomist and Professor Agronomy and Soils Auburn University William J. Moar Associate Professor, Entomology and Plant Pathology Auburn University C. Dale Monks Associate Professor and Extension Specialist Agronomy and Soils Auburn University Don P. Moore Superintendent Prattville Research Field Gary L. Mullen Professor, Entomology and Plant Pathology Auburn University Bobby E. Norris Superintendent Tennessee Valley Research and Extension Center Belle Mina, AL Michael G. Patterson Professor, Agronomy and Soils Auburn University Malcomb E. Pegues Assistant Superintendent Gulf Coast Research and Extension Center Fairhope, AL K. Rajasekaran USDA/ARS, Southern Regions Center New Orleans, LA Wayne Reeves Soil Scientist USDA-ARS Soil Dynamics Lab S. Saka USDA/ARS/CSRL Mississippi State University Hamidou F. Sakhanokho Graduate Student, Plant and Soil Science Alabama A&M University Govind C. Sharma Professor and Chair, Plant and Soil Science Alabama A&M University Ron H. Smith Professor and Extension Entomologist Entomology and Plant Pathology Auburn University Khairy Soliman Professor, Plant and Soil Science Alabama A&M University Glenn Wehtje Professor, Agronomy and Soils Auburn University Larry W. Wells Superintendent Wiregrass Research and Extension Center Headland, AL Allan Zipf Research Assistant Professor, Plant and Soil Science Alabama A&M University VARIETY TRIALS CHEROKEE COUNTY COTTON VARIETY TRIAL Charles Burmester and David Derrick A cotton variety trial was conducted in the northeastern cor- ner of Alabama in 1999. This area is a large cotton growing area with unique soil types that are not represented in the state cotton variety trials. The trial was conducted in Cherokee Country, Ala- bama, on the farm of Randall and Nick McMichen. The area had Holston fine sandy loam soils. Plots were planted on May 5 and consisted of eight rows of each variety planted the length ofthe field. Each variety plot mea- sured approximately 0.5 acres. The cotton variety Deltapine DP 458BRR was used as a check variety between each plot. TABLE 1. CHEROKEE COUNTY COTTON YIELD RESULTS 1 Variety Seed cotton Lint Lint yield lbs/ac % lbs/ac Paymaster PM1220BG/RR 3366 44 1480 Sure-Grow 125BR 3280 42 1380 Deltapine DP 409BRR 3220 41 1320 Deltapine DP 458BRR 2990 43 1290 Deltapine DP 422BRR 3073 40 1230 Sure-Grow 501BR 2902 42 1220 Deltapine DP 451BRR 3140 38 1190 Sure-Grow 485RR 2711 42 1140 Sure-Grow 125RR 2639 42 1110 I Deltapine DP 458BRR was used as a check between each variety. Since yield differences between 458 plots were small, no yield adjustments were needed. This area received a few timely rains in July and August that benefited the cotton greatly. Insects were not a major prob- lem in 1999. Bollworms were scouted and controlled with pyre- throid applications in the varieties without Bt genetics. Plots were harvested on September 24. All varieties pro- duced excellent yield (Table 1). All varieties were spindled picked and seed cotton weighed with a boll buggy. A seed cotton sample was collected from each variety for lint percent and quality pa- rameters. Cotton quality results are presented in Table 2. Results of this nonreplicated strip trial should be used as a guide in conjunction with result from the Alabama Cotton Vari- ety Tests. TABLE 2. CHEROKEE COUNTY COTTON QUALITY RESULTS Variety Micro- Length Uni- Strength naire formity Deltapine 458BRR 5.1 1.10 84 30.0 Sure-Grow 125BR 4.5 1.07 82 28.5 Sure-Grow 485RR 4.3 1.10 85 32.0 Sure-Grow 501BR 4.5 1.04 81 30.0 PM 1220BG/RR 4.6 1.07 82 30.5 Sure-Grow 125RR 4.4 1.05 83 29.0 Deltapine DP 451BRR 4.2 1.14 81 29.0 Deltapine DP 422BRR 4.2 1.09 83 29.0 Deltapine DP 409BRR 4.0 1.08 79 30.0 EVALUATION OF TRANSGENIC COTTON VARIETIES IN ULTRA-NARROW ROW AND NO-TILL PLANTING SYSTEMS E. Cebert and U.R. Bishnoi The objective of this research was to determine the effect of tillage, row spacing, and timing of Roundup application on yield of Bt/RR cotton. A transgenic cotton cultivar was planted through conven- tional tillage and ultra-narrow row (UNR) on May 8 and April 22, respectively, to compare application of Roundup after four and six weeks of planting. The cultivar Deltapine DP 425BRR was planted in conventional 40-inch row spacing and UNR spac- ing of 7.5 inches in a randomized complete block design with four replications. Plots were located on the Tate Farm in Madison County, Alabama. Rotindup was applied on May 21 and June 8 in the conven- tional plots and on June 6 and June 22 in the UNR plots. Data on plant population, number of opened bolls and seed cotton yield were collected and analyzed to determine potential significant differences between the different systems of production and tim- ing of Roundup application. Differences between the application of Roundup after four and six weeks were not significant in seed cotton yields and num- ber of bolls opened. The significant difference observed in plant population was a response to row spacing and seeding rate, rather than Roundup application. The increased number of plants per rwllv l vvvu vvrrvi I LIIIC LIIIC 2 ALABAMA AGRICULTURAL EXPERIMENT STATION square meter in the UNR system compensated for the low num- ber of bolls per plant (Tables 1 and 2). Plants in conventional row TABLE 1. RESPONSE OF TRANSGENIC COTTON TO TIME OF ROUNDUP APPLICATION AND TILLAGE SYSTEMS Roundup Open Seed cotton application date Plant bolls yield rrr 2 lbs/ac No-till and UNR June 22 44.8 a 55.7 ab 1819 a June 8 41.5 b 62.0 a 2232 a Conventional tillage and row spacing May 21 11.2 c 60.0 ab 2169 a June 6 9.2 d 45.5 b 2066 a Means with the same letter are not significantly different at p=0.05. spacing produced on the average five open bolls compared to less than two for UNR cotton. TABLE 2. COMPARATIVE PERFORMANCE OF ULTRA- NARROW AND CONVENTIONAL Row SPACING IN TRANSGENIC COTTON 1 Open Seed cotton Row spacing Plant bolls yield rrr 2 lbs/ac Ultra-narrow 43.1 a 58.9 a 2008 a Conventional 10.2 d 52.7 a 2117 a I Ultra-narrow row spacing was 7.5 inches; conventional row spacing was 40 inches. Means with the same letter are not significantly different at p=0.05. VARIETY EVALUATION IN ULTRA-NARROW Row COTTON AT E.V. SMITH AND PRATTVILLE Dennis P. Delaney, C. Dale Monks, Jim Bannon, Don P. Moore, and B. Durbin The interest in ultra-narrow row (UNR) cotton has lead to many research areas that need to be investigated. Since variety selection is one of the most important decisions for producers to YIELDS OF ULTRA-NARROW ROW COTTON make, trials were established at Tallassee, Alabama, and Prattville bama, in 1999 to evaluate seven VARIETIES -Prattville Research Field--- E.V. Smith Research Center Variety Seed cotton yield Lint yield Lint yield lbs/ac lbs/ac lbs/ac Sure-Grow 125 3989 1396 1740 Sure-Grow 125BR 4095 1433 1799 Sure-Grow 501BR 4201 1470 1657 Paymaster PM 1220BG/RR 4033 1411 1751 Paymaster PM 1330BG 3983 1394 1593 Paymaster PM 1560BG/RR 4151 1453 1638 Terra 292 3939 1379 1654 Stoneville ST 474 3877 1357 1496 Stoneville BXN 47 3933 1377 1589 PhytoGen PSC 355 3566 1248 1732 PhytoGen PSC 556 3304 1157 1487 FiberMax 989 3883 1359 1689 FiberMax 832 3641 1274 1654 Deltapine DP 20B 3877 1357 1571 Deltapine NuCotn 33B 4008 1403 1573 Deltapine DP 458BRR 3504 1227 1554 Deltapine DP 655BRR 4057 1420 1644 Deltapine Acala 90 3771 1320 1523 AgriPro AP6101 3584 1255 1610 AgriPro HS44 3759 1316 1564 LSD 346 121 141.2 E.V. Smith Research Center, Research Field, Prattville, Ala- al picker type selections in the UNR system. UNR plots were planted in early May at the E. V. Smith Research Center and Prattville Research Field into a tilled seedbed using a plot drill. Experimental de- sign was a randomized com- plete block with four repli- cations. A predetermined number of seeds were planted in each plot. Conven- tional soil-applied herbicides were used to control weeds. Data collected were seed cot- ton and/or lint yields. See table for variety evaluations. 1v0-I111 anu uiun 1999 ConaN RESEARCH REPORT 3 CROP PRODUCTION EVALUATION OF ROUNDUP READY COTTON IN ULTRA-NARROW Row SYSTEMS Charles Burmester The objective of this test was to evaluate different cotton varieties in an ultra-narrow row system and to determine if these varieties respond differently to Roundup applications applied af- ter the fourth leaf stage. Plots were planted on Mayl5 with Deltapine DP 458 BRR, Sure-Grow 125BR, and Paymaster PM 1220BG/RR at the Ten- nessee Valley Research and Extension Center in Belle Mina, Ala- bama. Plots were 12 feet wide and 30 feet long and were arranged in a randomized complete block design with four replications. Stand counts were determined on June 2 and plant height mea- sured on July 21 and August 6. The number of nodes per plant and nodes above white flower were determined on July 21 and August 6, respectively. Plots were harvested on October 5 and scrapped on October 15. The cotton stand was a little irregular especially in the Pay- master PM 1220BG/RR plots. However, this should not have af- EFFECT OF ROUNDUP READY COTT Treatment Rate Roundup Ultra 0.75 lb/ac Roundup Ultra 0.75 lb/ac Paymaster PM 1220BG/RR Cotoran 1.0 Ib/ac Caparol 1.5 pts/ac Roundup Ultra 0.75 Ib/ac Staple Select Paymaster PM 1220BG/RR Roundup Ultra 0.75 lb/ac Roundup Ultra 0.75 lb/ac Deltapine DP 458BRR Cotoran 1.0 lb/ac Caparol 1.5 pts/ac Roundup Ultra 0.75 lb/ac Staple Select Deltapine DP 458BRR Roundup Ultra 0.75 Ib/ac Roundup Ultra 0.75 Ib/ac Sure-Grow 125BR Cotoran 1.0 Ib/ac Caparol 1.5 pts/ac Roundup Ultra 0.75 lb/ac Staple as needed Select as needed Sure-Grow 125BR LSD (0.10) ' Stand per nine square feet. Mean fected the results. After the second Roundup application (applied with Bidrin and Pix), leaf bum was noted. This apparently stunted the cotton (see table, height measurements on August 6). During plant mapping, cotton treated with Roundup only at the fourth leaf stage had many more open bolls than cotton treated with Roundup at the fourth and eighth true leaf. Bolls were pulled in two areas of each plot for a total har- vest area of 36 square feet. Cotton was ginned on a small table top gin for lint percent. The plots with Roundup applied at the fourth leaf were harvested on October 5. The plots with Roundup ap- plied at the eighth leaf stage could not be harvested until October 15 due to late maturity. Yields (see table) of all varieties were greatly reduced where Roundup was applied at the eighth leaf stage. It is possible that combining Roundup with Bidrin and Pix in that application also increased the damage. ON ON CoT-ON STAND, PLANT HEIGHT, NODES, NODES ABOVE WHITE FLOWER, AND YIELD Growth Stand' - Height (in)- Nodes NAWF Yield stage June 2 July 21 Aug. 6 July 21 Aug. 6 lbs/ac 3-4 leaf 19.8 c 21.9 ab 23.8 b 13.1 a 2.5 bc 740 c 81h leaf pre pre 3-4 leaf as needed as needed 3-4 leaf 81 leaf pre pre 3-4 leaf as needed as needed 3-4 leaf 81 leaf pre pre 3-4 leaf as needed as needed 25.6 bc 21.9 ab 25.7 a 12.5 ab 2.6 abc 1384 a 26.5 bc 20.5 b 19.6 d 12.8 ab 2.3 c 819 c 36.4 a 20.9 ab 21.5 c 12.2 b 2.4 bc 117 b 32.4 ab 21.4 ab 22.9 bc 12.1 b 2.8 ab 866 c 25.5 bc 22.5 a 26.5 a 12.2 b 29.a 1342 a 6.60 1.63 1.84 0.76 0.35 162.1 s with the same letter are not significantly different at the p=0.10 level. L>UI~'UI~IW IL3UI\, illlll TL1VIIIZL~LCI T1V1 ILL\I~\JIZ\T\ ;dL LIIC ICII~ 1999 COTTON RESEARCHREPORT 3 i i 4 ALABAMA AGRICULTURAL EXPERIMENT STATION COVER CROPS AND TILLAGE METHODS FOR ULTRA-NARROW Row AND WIDE Row COTTON Dennis P. Delaney, Wayne Reeves, C. Dale Monks, and Brian E. Gamble Ultra-narrow row (UNR) cotton acreage has been rapidly increasing in Alabama in the last three to four years. Producers have become interested in UNR cotton as a way to save on ma- chinery costs and possibly increase yields on marginal land. Pre- vious research in Alabama has shown increased yields with the use of conservation tillage and lupin/legumes as winter cover crops for UNR cotton. This experiment was initiated in 1998 to investi- gate the optimum combination of row spacing (wide versus UNR), cover crops (legume versus rye), and tillage (conventional versus no-till). Plots were planted at the Wiregrass Research and Extension Center in Headland, Alabama. Rye was planted as a cover crop during the fall of 1997 and 1998, lupin was planted in 1997, and a lupin/crimson clover mix was planted in 1998 due to winterkill the previous year. Cover crops were killed at least one month before planting cotton and rolled down on no-till plots or incor- porated on conventional plots. All plots were paratilled each spring. Paymaster PM 1220BG/RR cotton seed was planted in May of each year, but was replanted in June 1998 due to extremely dry weather. UNR (eight-inch) plots were planted at 182,000 seeds per acre and wide-row (36-inch) plots at 84,000 seeds per acre each year. The experimental design was a split-strip-strip arrange- ment oftreatments with four replications. Data collected included plant populations, leaf area indices, and seed cotton and lint yields. In 1998 plant population counts showed that UNR had a higher population than wide row with 148,000 versus 38,000 plants per acre, respectively. In 1999 plant populations of 37,000 plants per acre were seen in wide row, 139,000 in conventional UNR, and 98,000 in no-till UNR. Leaf area index (LAI) measurements showed a significant interaction between row width x cover x tillage. UNR cotton con- sistently had a higher LAI than wide row at early bloom. In 1999, there was a tillage x row width interaction, again with UNR hav- ing a much higher LAI at this growth stage. Lint yield measurements showed that UNR systems yielded higher (911 versus 596 pounds per acre) than wide row in 1998, with no interactions. In 1999, there was a tillage x cover interac- tion, but no row width effect. Conventional tilled plots after le- gumes yielded 949 pounds per acre versus 865 pounds per acre for no-till after legumes. After rye, conventional yielded 923 pounds per acre and no-till 669 pounds per acre. It appeared that early season leaching and slow breakdown of cover crops in late season might have caused nitrogen deficiency in no-till rye plots. Based on two years of data, it appears that UNR cotton took ad- vantage of higher early season intercepted sunlight (LAI) to yield better than wide row cotton in a year with a dry early summer that slowed late season growth. In a year with a wet early spring and dry late summer, wide row cotton continued growth through late bloom and yielded the same as UNR. In that year, no-tilling de- creased yields, while cover crops had a variable effect. GROWTH REGULATOR EFFECTS ON COTTON Dennis P. Delaney, C. Dale Monks, Jim Bannon, and B. Durbin Growth regulators have been used for the past several years to promote and/or control vegetative growth in cotton. Each year trials are conducted to compare established products with new products that will be coming to the market. A study was con- ducted in 1999 to compare Pix Plus, Pix Ultra-an experimental growth regulator with Pix-and an untreated control. In early May 1999 DeltapineNuCotn 33B cotton was planted conventionally at the E.V. Smith Research Center, Shorter, Ala- bama, on raised beds. Plots were 30 feet long and four rows wide. Standard fertility and weed control practices were followed. Plots were irrigated throughout the season with a traveling gun system. The experimental design was a randomized complete block with four replications. All treatments were applied at eight fluid ounces of product per acre with a backpack sprayer in 15 gallons per acre solution. Activate Plus was also added to each treatment. Treat- ments were applied at the pinhead to matchhead square stage and again at the late matchhead square stage at 12 fluid ounces per acre. Data collected were plant height, nodes above white flower, fruit retention, fruiting branches, and retention on the first fruit- ing position on August 16; open, closed, and total bolls on Sep- tember 3; plant height and seed yield on September 23; and lint turnout. Most of the parameters measured did not indicate a differ- ence between treatments including the untreated control. The major differences noted were height and earliness when the treatments were compared to the untreated control and the increased earli- ness of Pix compared to Pix Ultra and Pix Plus. Final yields did not differ between treatments. IIV11) VI11~V IV 1999 COTTON RESEARCH REPORT 5 EFFECTS OF BORON AND MEPIQUAT CHLORIDE TIMING ON IRRIGATED COTTON GROWTH AND YIELD Charles Burmester Different formulations of a cotton growth regulator, mepiquat chloride, were evaluated for controlling cotton growth and in- creasing yields on irrigated cotton. The standard mepiquat chlo- ride formulation, Pix Plus, was compared to a new experimental formulation, Pix Ultra. A foliar boron treatment was also added to evaluate possible boron and growth regulator interactions. The cotton variety Deltapine NuCotn 33B was planted on May 5, at the Tennessee Valley Research and Extension Center, Belle Mina, Alabama. Plots consisted of eight cotton rows 50 feet long arranged in a randomized complete block design with four replications. Early season growth regulator rates (0 to 12 ounces per acre) were applied at early square. The late season applica- tions of Pix Plus and Pix Ultra were applied in two applications of eight ounces per acre. The effects of the early season growth regulator rates were evaluated by monitoring plant height and node development. Cotton yields were taken by harvesting the four middle rows of each plot with a modified spindle cotton picker. The higher rates of Pix Plus and Pix Ultra decreased cotton plant height as expected at early square (Table 1). Differences, however, were not as dramatic as seen in 1998. Late season cot- ton height differences were much smaller than expected. Rates of the growth regulators and boron applications had little effect on cotton node development and growth (Table 2). Lint yields were very high and averaged almost three bales per acre (Table 1). The early season growth regulator rates, how- ever, had very little effect on yield and no growth regulator and boron interaction was found. TABLE 1. EFFECT OF Pix PLUS AND Pix ULTRA ON PLANT HEIGHT Treatment Rate Growth stage Plant height (in) Lint yield oz/ac June 10 June 21 June 30 July 12 July 21 Aug. 10 lbs/ac Pix Plus - matchhead square 13.75 a 22.65 a 32.15 a 41.3 a 45.0 a 48.5 a-d 1419 b Pix Plus 4 matchhead square 13.43 a 20.13 ab 26.48 def 36.0 cd 39.8 c 45.3 b-e 1458 ab Pix Plus 8 matchhead square 15.35 a 20.85 ab 26.05 ef 34.8 d 38.8 c 44.0 e 1497 ab Pix Plus 12 matchhead square 14.08 a 19.20 b 24.63 f 34.0 d 39.2 c 45.0 cde 1425 b Pix Ultra - matchhead square 14.50 a 22.33 a 30.38 abc 40.2 ab 44.1 ab 49.3 ab 1467 ab Pix Ultra 4 matchhead square 14.68 a 20.75 ab 27.85 cde 37.1 bcd 40.8 bc 49.2 abc 1463 ab Pix Ultra 8 matchhead square 14.62 a 19.92 ab 25.30 ef 35.7 cd 40.2 c 45.7 b-e 1464 ab Pix Ultra 12 matchhead square 15.40 a 20.60 ab 26.30 def 34.8 d 38.4 c 44.6 de 1487 ab Pix Plus + Boron - matchhead square 14.52 a 22.43 a 30.73 ab 40.5 a 46.3 a 50.3 a 1542 a Pix Plus + Boron 4 matchhead square 14.88 a 20.92 ab 28.92 bcd 38.3 abc 44.1 ab 48.7 a-d 1471 ab Pix Plus + Boron 8 matchhead square 15.68 a 20.65 ab 26.13 ef 35.1 cd 41.1 bc 46.6 a-e 1499 ab Pix Plus + Boron 12 matchhead square 15.63 a 20.15 ab 24.75 f 33.8 d 38.7 c 44.3 e 1456 ab LSD (0.10) 2.064 2.495 2.496 3.05 3.10 3.65 97.9 Means with the same letter are not significantly different at the p=0.10 level. TABLE 2. EFFECT OF PIX PLUS AND Pix ULTRA ON NUMBER OF NODES AND NODES ABOVE WHITE FLOWER Treatment Rate Growth stage -Total nodes- - Nodes above white flower- oz/ac June 10 July 12 July 12 July 21 July 29 Pix Plus - matchhead square 8.9 a 14.0 ab 7.2 abc 5.4 c 4.6 a Pix Plus 4 matchhead square 8.6 a 13.5 ab 7.4 abc 5.2 c 5.0 a Pix Plus 8 matchhead square 9.1 a 13.7 ab 7.1 abc 5.6 abc 4.3 a Pix Plus 12 matchhead square 8.6 a 13.5 ab 7.1 bc 5.7 abc 5.0 a Pix Ultra - matchhead square 8.9 a 14.3 a 7.7 ab 5.6 abc 4.6 a Pix Ultra 4 matchhead square 9.0 a 13.1 ab 7.2 abc 5.4 bc 4.9 a Pix Ultra 8 matchhead square 8.9 a 13.7 ab 7.3 abc 5.5 bc 4.7 a Pix Ultra 12 matchhead square 9.2 a 13.4 ab 6.9 c 5.3 c 4.7 a Pix Plus + Boron - matchhead square 8.8 a 13.8 ab 7.8 a 6.1 a 4.6 a Pix Plus + Boron 4 matchhead square 8.9 a 13.5 ab 7.2 abc 5.9 ab 4.5 a Pix Plus + Boron 8 matchhead square 9.1 a 12.9 b 7.1labc 5.7 abc 4.8 a Pix Plus + Boron 12 matchhead square 8.7 a 13.2 ab 7.3 abc 5.6 bc 4.5 a LSD (0.10) 0.51 1.07 0.56 0.43 0.65 Means with the same letter are not significantly different at the p=0.10 level. EFFECTS OF DIMILIN AND BORON ON COTTON Dennis P. Delaney, C. Dale Monks, Jim Bannon, and B. Durbin Dimilin and boron have been used to promote growth and control insects in soybeans for the past several years. There is currently work underway to evaluate the same system for use in cotton. This trial was conducted to evaluate the following treat- ments: Dimilin at two ounces per acre applied four times begin- ning at pinhead square, Dimilin at four ounces applied four times beginning at pinhead square, Dimilin at four ounces applied two times beginning at full bloom, Dimilin plus Solubor applied two times starting at full bloom, Solubor applied two times beginning at full bloom, and an untreated control. Deltapine NuCotn 33B cotton was planted using conven- tional methods at the E. V. Smith Research Center in Shorter, Alabama, in early May on raised beds in plots 30 feet long and four rows wide. Standard fertility and weed control practices were followed. Plots were irrigated throughout the season with a trav- eling gun system. All treatments were applied with a backpack sprayer in 15 gallons per acre solution. Experimental design was a randomized complete block with six replications. Data collected were total open and closed bolls on September 10; and total nodes, fruit retention on the first and second positions, fruit retention by node zones 6-10 and 11-15, and seed cotton yield on September 23. There were few differences noted between treatments for most of the parameters measured. The only differences were in retention on nodes 11-15 between the two- and four-ounce rate of Dimilin and the total node counts between the two ounces of Dimilin and the Dimilin/Solubor combination. No differences in earliness or yield were noted. ALABAMAAGRICULTURALExPERIMENT STATION 6 1999 COTTON RESEARCH REPORT 7 COTTON RESPONSE TO PHOSPHORUS IN ALABAMA'S LONG-TERM EXPERIMENTS Charles C. Mitchell Alabama's early phosphorus (P) recommendations were based on P-rate experiments maintained by the Alabama Agri- cultural Experiment Station on research substations in the major land resource areas of the state and on smaller experiment fields in minor soil regions. Six of these experiments, which were started in 1928, are still maintained today and are known as the Two- year Rotation experiments because they have always involved cotton, corn, sorghum, soybean, or peanut rotations. Five of these have included cotton since 1992. In order to maintain a sound research basis for its soil testing services, Auburn University and the Alabama Agricultural Experiment Station established addi- tional soil test calibration experiments in 1954 when the A.U. Soil Testing Laboratory began services. These new soil fertility experiments were known as the Rates of N-P-K experiments and have been continued at seven locations since their establishment. Five of the seven experiments have been planted in cotton every year since 1992. In spite of a strong research basis for soil testing in Ala- bama, producers and their consultants often question the validity of soil test interpretations. No doubt part of this is due to a wide range of interpretations available from different public and pri- vate soil testing services, opinions of consultants, and competi- tion for fertilizer sales. Emphasis on precision agriculture may have created expectations from soil testing beyond what it is ca- pable of delivering. Nevertheless, as producers adopt new tech- MEAN COTTON LINT YIELDS ON THE FERTILIZED CONTROL ROTATION AND RATES OF N-P-K EXPERIMENT Location Year Brewton Wiregrass Monroeville P lbs lint/ac Two-year Rotation (cotton-soybean rota 1992 1080 770 -- 1993 1080 550 800 1994 540 - 800 1995 1400 730 740 1996 1040 800 1020 1997 340 550 620 1998 620 - 890 Rates of N-P-K (cotton every year) 1992 760 950 420 1993 - 670 1250 1994 500 - 970 1995 - 790 900 1996 1030 830 1020 1997 930 620 820 1998 780 -- 1030 nologies, genetically improved varieties, and new production prac- tices, they expect and deserve periodic verification of soil testing interpretations from their public laboratories. The purpose of this study is to summarize cotton yield response to residual soil P since 1992 in order to validate or update Alabama's current soil test calibration for P using modem varieties with higher yield potentials. Cotton yields from P variable treatments on the Two-year Rotation and Rates of N-P-K experiments were compared with yields from a standard treatment, which received a full comple- ment of fertilizers (see table), to develop relative yields for each location and year. When Mehlich-1 extractable soil P was cali- brated with relative cotton yields for each of the experiments at each of the five locations, several locations and tests failed to demonstrate a response to increasing levels of residual soil P. Treatments on all soils except for the Lucedale sandy clay loam at Prattville Research Field would be rated "low" by the southern public soil testing laboratories. Failure to get dramatic responses all the time demonstrates the inherent difficulties of trying to make soil testing a definitive and infallible tool. However, when yield and soil data from both tests at all Coastal Plain locations over the entire seven-year pe- riod were pooled (see figures), a reasonable critical value for Mehlich-1 extractable P could be estimated. The current critical value used by the Auburn University Soil Testing Laboratory for these soils is 25 milligrams (mg) P per kilogram (kg) (50 PLOTS ON THE Two-YEAR pounds P per acre). rs, 1992-1998 The Soil Science Soci- ety of America defines criti- rattville Tennessee Valley cal soil test concentration as ... that concentration at ation) which 95% of maximum 1320 1270 relative yield is achieved... 650 1030 usually coincides with the 1340 1270 inflection point of a curvilin- 340 590 ear yield response curve." 930 930 Above this value, no fertilizer 1360 1070 P is recommended because 1080 810 the probability of a yield re- ) sponse is extremely low. Be- 1480 1490 low this value, P is recom- 660 920 mended in increasing incre- 1290 1180 ments. Alabama's critical 140 740 1280 1420 value is within the range used 1180 1170 by other public soil testing 1100 109 8 ALABAMA AGRICULTURAL EXPERIMENT STATION laboratories in the region for Mehlich-1 P and cotton on Coastal Plain soil (18 to 30 mg P per kg). The fine-textured soils of the Tennessee Valley have a high P fixation capacity and a lower critical P value as currently used by the Auburn University Soil Testing Laboratory. These data verify the current value of 15 mg P per kg for these soils (see figures). Based on a comparison between Deltapine NuCotn 35B and Deltapine DP 5690 cultivars at the Prattville Research Field from 1996 to 1998 on the Rates of N-P-K experiment in split plots, there is no difference in responsiveness to residual soil P. How- ever, the new Bollgard? variety, Deltapine NuCotn 35B, aver- aged 80 pounds lint per acre per year more than the conventional variety. Soil test calibration for cotton using Mehlich-1 extract on five Alabama soils during 1992-1998 indicated that critical val- ues in use by state soil testing laboratories in the southeastern United States are well within reason for new cultivars and mod- ern cultural practices. There is no need to adjust the critical values currently in use in Alabama. These critical values are 25 milli- grams P per kilogram for soils with a cation exchange capacity (CEC) less than nine centimoles per kilogram (cmol/kg) (Coastal Plain soils) and 15 milligrams extractable P per kilogram for soils with a CEC less than nine cmol/kg (limestone valley soils). Based on a comparison between Deltapine NuCotn 35B and Deltapine DP 5690 cultivars, there is no difference in responsiveness to re- sidual soil P. Mehlich-1 soil test calibration for cotton based on data from Alabama's Two-year Rotation and Rates of N-P-K experiments at five Alabama locations. Shaded area includes the current critical Mehlich-1 extractable P values used by public soil testing laboratories in Alabama, Georgia, Florida, South Carolina, and Tennessee. All Coastal Plain soils in these experiments had CEC < 9.0 cmol/kg. 120 100 80 o 60 0 20 Current critical soil test P used in Alabamau * 2-Yr Rot. E NPK Test 0 10 20 30 40 50 60 MI-extractable P (mglkg) Tennessee Valley Soils 140 120 100 80 60 40 20 -o 0 , 0 0 Al 0 20 40 60 80 100 MI-extractable P (mglkg) Coastal Plain Soils 1999 CanoN RESEARCH REPORT 9 NITROGEN RATES FOR COTTON IN ALABAMA'S LONG-TERM EXPERIMENTS Charles C. Mitchell Although nitrogen (N) is the most difficult nutrient to man- age in cotton production, it has more impact on yields, earliness, and lint quality than any other primary plant nutrient. It is also the most costly plant nutrient applied per acre. Potential nitrate-N leaching into ground waters is a driving force behind water qual- ity issues and nutrient management planning policies. As higher yields become possible with new, genetically modified varieties, growers legitimately question older research upon which stan- dard N recommendations are made. Some laboratories adjust N recommendations based upon realistic yield goals. In order to reexamine the effects of N rates on new cotton varieties with higher yield potentials, seven years of cotton yield data from existing, long-term soil fertility experiments (1992 through 1998) were summarized. Since 1996, Bollgard? and Roundup Ready@ varieties have been used at most locations. Ex- periments summarized are known as the Two-year Rotation ex- periment (circa 1929) and the Rates of N-P-K experiment (circa 1954) at five locations. The Two-year Rotation is a cotton-soy- bean rotation with N rate variables for the cotton and the Rates of N-P-K experiment is in cotton every year. Results support the current standard N recommendations used on soil test reports. For most sandy and loamy Alabama soils, the standard recommendation is a total of 90 (plus or minus 30) pounds N per acre during the growing season; 60 (plus or minus 30) pounds N per acre is standard for the deep, red silt and clay loams of the limestone valleys of North Alabama (Figure 1). The comment with current recommendations recognizes that residue from a good soybean or peanut crop may contribute 20 to 30 pounds N per acre to the following cotton crop. Because as many as six months could elapse between soybean/peanut har- vest in the fall and cotton planting the following April or May, much of the residual N may be lost from the soil. Data from N- rate treatments on the Two-year Rotation at five locations verify the variable nature of residual N from legumes (Figure 1). Since 1992, cotton on this experiment has always followed soybean or peanut. Clearly, cotton response to N rates was highly variable following a legume. Promoters of fertilizer use have often espoused the SOILS IN ALABAMA'S L concept of recommendations Location based on yield goals. This is wton Research Field a particularly popular and reasonable practice with Wiregrass Research grain crops such as corn, and Extension Center wheat and sorghum, and for- Monroeville Research Field ages. These crops remove large quantities of N in the Prattville Research Field harvested portion of the crop. Tennessee Valley Research and Extension Center However, Alabama's long-term N experiments do not support this practice for cotton under the conditions of these experiments. All five sites had similar results, so only three of the sites are presented in Figure 2. In a disaster year when cotton yields are less than a bale per acre, very little if any N fertilizer is needed. No farmer plans on a disaster year and never fertilizes for these situations. But even in outstanding production years when yields far exceed anticipated yield goals (e.g., more than three bales per acre), data from Alabama's research stations support the "stan- dard" recommendation plus or minus about 30 pounds N per acre. Because of the rapid adoption of the new, genetically modi- fied cotton varieties, there have been few opportunities to evalu- ate their response to soil fertility variables. In 1996, the first year Bollgard? varieties were available to Alabama producers, the Rates of N-P-K experiment on a Lucedale sandy clay loam at the Prattville Research Field was modified to determine if any differ- ences existed in response to soil fertility variables between two varieties of similar genetic backgrounds. All plots were split and a Bollgard? variety, Deltapine NuCotn 35B, was planted on half of each plot in three, 40-inch rows, 25 feet long, and a conven- tional variety of similar genetics, Deltapine DP 5690, was planted on the other half of each plot. There were significant differences due to N rate and variety each year. The Deltapine NuCotn 35B yielded an average of 85 pounds more lint per acre per year than the conventional variety over all N rates. Long-term, N-rate research at several Alabama locations since 1992 supports the current standardN recommendations used on soil test reports. For most sandy and loamy Alabama soils, the standard recommendation is a total of90 (plus or minus 30) pounds N per acre during the growing season; 60 (plus or minus 30) pounds N per acre is standard for the deep, red silt and clay loams of the limestone valleys of North Alabama. Cotton following a good soybean or peanut crop will benefit from some residual N but predicting this response has been difficult. While N recommen- dations based on a yield goal may apply for some crops, this clearly is not the case with nonirrigated cotton in Alabama. Producers ONG-TERM SOIL FERTILITY EXPERIMENTS WITH COTTON Soil type Benndale loamy sand (coarse-loamy, siliceous, thermic Typic Paleudults) Dothan sandy loam (fine-loamy, siliceous, thermic Plinthic Kandiudults) Lucedale fine sandy loam (fine-loamy, siliceous, thermic Rhodic Paleudults) Lucedale sandy clay loam (fine-loamy, siliceous, thermic Rhodic Paleudults) Decatur silt loam (clayey, kaolinitic, thermic Rhodic Paleudults) 1999 COTTON RESEARCHREPORT 9 10 ALABAMA AGRICULTURAL EXPERIMENT STATION should follow the standard N recommendation on new fields and make adjustments as experience and cropping systems dictate. Nitrogen rates do not need to be adjusted for the newer, geneti- cally modified cotton varieties. Figure 1. Nitrogen rates where cotton is planted every year (Rates of N-P-K Test) and cotton following soybean (Two-year Rotation experiment) at five Alabama locations, 1992-1998. Relative yield is the lint yield compared to the lint yield of a treatment receiving 90 pounds N per acre. All N is applied in split applications. ~-IUU - o90. >% 80.. > 4 Coastal Plain soils S70 L imecstone ~ 0 Valley soils 50 0 30 60 90 p120 150 N rate (lblacre) All Sites: Continuous cotton on "Rates of N-P-K Test" as: 110 100 90. 80 70 60 50 40 301 Tennessee Valley Msaate orsCoastal Main ~tsites 0 30 60 90 120 150 N rate (Iblacre) All Sites: Cotton following soybean on"Two-Year Rotation" Figure 2. Cotton yield response to nitrogen rates on the "Rates of N-P-K Test" (c. 1954), 1992-1998, at five Alabama locations. Lines represent the highest yielding year, the lowest yielding year, and the mean of seven years E 5* .O1400 2?1200 -~1000 ~.800 S600 .~400 *~200 .j 0 0 30 60 90 120 150 N rate (lblacre) Brewton: Benndale loamy sand (U C 1400 1200 1000 800 600 400 0 30 6 0 90 120 150 N rate (Iblacre) Prattville: Lucedale sandy clay loam * 0 30 60 90 120 150 N rate(Iblace) Tennessee Valley: Decatur silt loam (U -D C io o 1600 1400 1200 1000 800 600 400 ALABAMAAGRICULTURALEXPERIMENT STATION 10 lic 1999 COTTON RESEARCH REPORT POTASSIUM NUTRITION OF COTTON Charles C. Mitchell and Gary L. Mullen Potassium (K) nutrition of crops on acid, infertile soils of the southeastern United States (Table 1) has always been a con- cern, especially for cotton, which is susceptible to K deficiencies. With increasing acreage and yields of cotton on these soils, new varieties, eradication of the boll weevil, and new technologies for insect control, K nutrition is of renewed concern to growers. Alabama's Two-year Rotation experiments at six locations (circa 1929) have provided information for fertilizer recommendations and data for soil test calibration since their beginning. In 1982, these experiments were put into a residual phosphorus (P) and K mode. Cotton has been a principal crop in these experiments for 46 of the 69 years from 1929 to 1997. Therefore, these experi- ments offer an excellent opportunity to study soil K changes with time and reevaluate K nutrition of cotton. The objective of this summary is to reexamine soil test calibration for K on cotton. In order to accomplish this objective, soil K variable treatments on the Two-year Rotation experiment at five Alabama locations were summarized from 1992 through 1998. Alabama's Two-year Rotation soil fertility experiments at 11 ON LONG-TERM EXPERIMENTS TABLE 1. CALIBRATION OF M1 EXTRACTABLE POTASSIUM FOR COTTON IN SOUTHEASTERN UNITED STATES State Low Medium High mg/k Alabama CEC<4.6 <30 31-60 60+ CEC<9 <45 45-90 90+ CEC 9+ <60 61-120 120+ Florida All soils <35 36-60 60+ Georgia Coastal plain <30 31-75 75+ Piedmont <50 51-100 100+ South Carolina All soils <35 36-78 78+ Virginia All soils <37 38-87 88+ five locations have been in a cotton-soybean rotation since 1992. plot was planted in Deltapine NuCotn 35B, a genetically modi- Four of the 17 soil fertility treatments were annual K variables fled variety containing the Bollgard? gene, which makes it resis- which were applied before 1982: (1) 0 K, (2) 28 pounds of K 2 0 tant to certain bollworms. The other half of each plot was planted per acre, (3) 60 pounds of K 2 0 per acre (standard treatment), and in Deltapine DP 5690, a conventional variety similar to the (4) 120 pounds of K 2 0 per acre. No fertilizer K has been applied Deltapine NuCotn 35B. The purpose of this was to see if there to K-variable plots since 1982 (i.e., residual K since 1982) except was any difference in response to K fertility. for the standard treatment, which continues treatment, to receive 60 pounds In 1982 when annual K applications ceased on all treatments of K 2 0 per acre per two-year rotation. In addition to the K vari- except the 60-pounds-of-K 2 0-per-acre treatment, the two highest ables, all plots received annual applications of 60 pounds of P 2 0 5 K treatments were at or above what was considered to be a"high" per acre before 1982, and all plots tested high in P. Plow layer soil soil test K level for cotton at all sites. A "high" soil test is above samples were tested every other year (after harvest) for Mehlich- an established critical value and is defined as an adequate supply 1 extractable K. of that nutrient; no additional application of that nutrient is rec- The Rates of N-P-K experiment was started in 1954 and has ommended. similar K variables as the Two-year Rotation. It has been in cot- Mean cotton lint yield from each residual K treatment was ton every year since 1992 at five locations. At the Prattville Re- compared with mean yield for the standard fertilization treatment search Field, plots were split in 1996 through 1998. Half of each that received 60 pounds of 20 per acre to calculate a relative yield (Table 2). Relative yield is expressed as a per- TABLE 2.MEAN COTTON LINTYIELDS FROM THE STANDARD FERTILIZED TREATMENT centage ofthe standard treat- IN THE TWO-YEAR ROTATION EXPERIMENTS, 1992-1998 ment yield. Relative yield by Location 1 _location and year was then Location' compared to the mean soil Year Brewton Wiregrass Monroeville Prattville Tennessee Valley compared to the mean soil lbs lint/acre test K value for each treat- ment at that location to de- 1992 1080 770 - 1320 1270 velop a soil test calibration 1993 1080 550 800 650 1030veo ote io 1994 540 - 800 1340 1270 for cotton forthe period 1992 1995 1400 730 740 340 590 through 1998 (Figure 1). 1996 1040 800 1020 930 930 Growers have been 1997 340 550 620 1360 1070 concerned that with higher 1998 620 - 890 1080 810 yielding, earlier maturing, 1 Soil type by location: Brewton (Bennedale loamy sand), Wiregrass (Dothan sandy loam), Monroeville modern varieties, soil test (Lucedale fine sandy loam), Prattville (Lucedale sandy clay loam), Tennessee Valley (Decatur silt loam). ALABAMA AGRICULTURAL EXPERIMENT STATION calibration for K on cotton needs adjusting. However, these data indicate that the sufficiency level approach to critical K values as used by the Auburn University Soil Testing program in Alabama and other southern states is still very reliable and accurate. The weakly buffered soils with a cation exchange capacity (CEC) less than or equal to 4.6 centimoles per kilogram (cmol kg-') (the Dothan and Benndale series) are included in one graph and the two Lucedale soils (CEC equals 4.6 to 9.0 cmol kg-') are included in another graph according to current Alabama soil test calibra- tion. The Decatur soil, which is representative of cotton produc- ing soils of the Tennessee Valley region, has the highest CEC (10.0 cmol kg-') and the highest critical soil test K level. The fine textured, highly buffered, smectitic and often calcareous soils of the Alabama Black Belt prairie region are tested with another extractant and have a different calibration not included in this study. Potassium recommendations for cotton are made using a linear regression for each of the three groups of soils designated by CEC. Recommendations decrease from 120 pounds K 2 0 per acre per year at the lowest soil test values to none at the critical soil test value. In a separate but related study, researchers found that cotton yields on the two Lucedale soils and on the Benndale soil were highly significantly related to soil test K in the 0 to 20 cm depth, in the 20 to 40 cm depth, and in the 40 to 60 cm depth. However, using soil test K from different depths did not improve soil test calibration. There were no significant differences in yield between Deltapine Nucotn 35B and Deltapine DP5690 nor was there any interaction between variety and K fertility at the Prattville Re- search Field in 1996 and 1997. Both varieties responded to re- sidual soil K similarly. However, in 1998, Deltapine Nucotn 35B produced higher cotton yields (mean lint yield = 1,050 pounds per acre) over all K treatment than did Deltapine DP5690 (mean lint yield = 920 pounds per acre), probably a result of less insect damage. Current soil test calibration critical extractable K values for Alabama soils are still accurate for modern varieties and yields. Plow-layer, soil test K is still a very reliable tool for predicting the need for K fertilization on Alabama soils when other factors are not limiting. There is no apparent need to adjust K fertilization for the new Bollgard? varieties. Potassium calibration for cotton based on current values in use by public soil testing laboratories using the Mehlich-1 extract and Alabama data from K variables on the Two-year Rotation experiment, 1992-1998. Shaded areas are the ranges in critical soil test K values in the southeastern United States. v B 7 nndaIl oDothanj 0 ot critical K values 0 20 40 60 80 100 120 140 160 M1 extractable K (mg/kg) Potassium calibration on soils with CEC <4.6 cmol/kg (Dothan sandy loam and Benndale loamy sand) S - Alabama's current critical C "K value 20 40 60 80 100 120 140 160 180 200 220 240 M1 extractable K (mg/kg) Potassium calibration on soils with CEC>9.0 cmol/kg (Decatur silt loam) K vlu 0 I 20~ 40 608 0 20101010 0 24 Mletatbl m/g Poasu airto nsol ihCC9Ocok (Dctrsl om On e) to2 3(D0 0 o o 0 a0 ofo 0 no0 Extractable K (mg/kg) Potassium calibration on soils with CEC 4.6-9.0 cmol/kg (Lucedale soils) 12 0 Go >0 at (1 C CC - ~0 cc SUMMARY OF 1999 ROUNDUP READY COTTON PRODUCED UNDER IRRIGATED AND NONIRRIGATED CONDITIONS IN NORTH ALABAMA C. Dale Monks, Rob Woods, Dennis P. Delaney, Bobby Norris, Charles Burmester, and Glenn Wehtje Roundup Ready cotton has been increasing in acreage since its introduction two years ago. Approximately 80% of the crop in Alabama in 2000 will be glyphosate tolerant. Studies were initi- ated at the Tennessee Valley Research and Extension Center, Belle Mina, Alabama, to evaluate the effects of glyphosate on irrigated and dryland (nonirrigated) cotton. Deltapine DP 458BRR cotton was planted and tillage was conducted with conventional procedures. Experimental design was a 2 x 4 factorial arrangement of treatments in a completely ran- domized design. This arrangement meant that both irrigated and nonirrigated plots were treated with four factors, which were three levels of glyphosate treatments and a control. The fertility program included 100 pounds per acre of 0-0- 60 fertilizer applied on March 4, one ton per acre of lime on March 18, 75 pounds per acre of nitrogen (34-0-0) on March 24, and 30 pounds per acre of liquid nitrogen applied to irrigated plots on May 27. A field cultivator was used on March 26 and April 13. Treflan (one pint per acre) was applied and a vertical action tiller with rolling baskets was used for final seedbed preparation on April 19. Cotton was planted on April 19 with Temik (five pounds per acre) plus Terraclor SuperX (six pounds per acre) applied in the seed furrow. Weed control measures included Cotoran (1.8 pounds per acre) plus Caparol (1.5 pints per acre) applied preemer- gence after planting. Roundup Ultra treatments (one quart per acre) were applied on May 25 (four-leaf) and/or June 18 (directed). Cotton was defoliated on September 17 with Finish (one quart per acre) plus Ginstar (three ounces per acre) and harvested on October 4. A total of 16 ounces per acre of Pix was applied to dryland plots and 24 ounces per acre were applied to irrigated plots. Data were collected from 30 plants and included visual injury observations, plant mapping, seed cotton and lint yield, and boll char- acteristics by node. No crop injury was observed on any treatment compared to the untreated control. Boll counts and seed cotton yield indicated no difference in boll opening caused by the herbicide treatments. Nonirrigated plots were 66% open in September compared to 20% open for irrigated plots. Nonirrigated plots yielded 1,610 pounds per acre seed cotton compared to 3,420 pounds per acre in irri- gated plots. Micronaire (mic), length, and strength readings were lower in nonirrigated plots with 3.2 versus 4.1 mic, 1.06 versus 1.11 inches staple length, and 25 versus 29 grams per tex for the nonirrigated compared to irrigated treatments, respectively. Yield was distributed in the lower fruiting nodes in the nonirrigated plots but was more evenly distributed in the mid- to upper-nodes in the irrigated plots. 1999 CorrONRESEARCHREPORT 13 INSECTICIDE APPLICATIONS COMPARISON OF SELECTED IN-FURROW TREATMENTS FOR THRIPS CONTROL IN COTTON Barry L. Freeman The objective of this research was to compare at-plant ap- plications of two in-furrow liquid treatments to an in-furrow granu- lar treatment and an untreated control. Plots were planted April 21 with Deltapine NuCotn 33B cotton at the Tennessee Valley Research and Extension Center, Belle Mina, Alabama. Plots consisted of four rows 25 feet long with a 40-inch wide row spacing and were arranged in a random- ized complete block with four replications. Plots were harvested September 28. Admire was applied at rates below those recommended for experimental purposes only. Plots were maintained according to Alabama Cooperative Extension System recommendations for weed control, fertility, and insect control following at-planting insecticide treatments. Five. rnndnm rlnants from each plot were sampled by being rinsed in 70% ethyl alcohol. Specimens were subsequently filtered and counted under a stereoscope. Adult and larval thrips were tallied separately. Adult thrips specimens were mounted on microscope slides in CMC-10 medium and sent to Texas A&M Uni- versity for determination of species. Each plot was rated for damage on a system from 0- 5(0= no damage and 5= ex- treme damage). Evaluations were made on May 7, May 14, May 21, May 27, and June 7. Damage was rated on May 21 and May 27. Plant population was determined on June 9. All living plants in the center two rows of each plot were counted. All white blooms were counted from the center two rows of each plot on July 6 through July 9 as an indication of earliness. All insecticide-treated plots produced more plants than the control treatment. The Admire and Temik treatments had higher plant populations than the Admire + Orthene treatment. The con- trol treatment revealed severe thrips damage on both evaluation dates. Temik and Admire treatments showed moderate damage on May 21, but plants had outgrown some ofthis damage by June 16. The Admire + Orthene treatment revealed heavy thrips injury on May 21, but by June 16 these plots had recovered substan- tially. Larval and total numbers of thrips were much higher from the control treatment than from all insecticide treatments on each sample date. Insecticide treatments contained moderate thrips re- production throughout the sample period with the Admire + TABLE 1. EFFECT OF INSECTICIDES ON NUMBER OF ADULTTHRIPS BY SPECIES' Treatment Sample Tobacco Western flower Flower Soybean Others Aphids date thrips thrips thrips thrips Admire May 7 4 (57)2 3 (43) 0 0 0 0 May 14 21 (95) 0 0 1(5) 0 0.25 May 21 0 3(100) 0 0 0 0.25 May 27 8(53) 7(47) 0 0 0 0.25 June 7 0 1 (9) 2(18) 8(73) 0 1.25 Totals 33 (57) 14(24) 2 (3) 9 (16) 0 0.50 Admire + Orthene May 7 11 (85) 1 (8) 0 1 (8) 0 0 May 14 32(80) 4(10) 3(8) 1(3) 0 0 May21 4(44) 4(44) 0 1(11) 0 1.5 May 27 7(29) 11(46) 3(13) 0 3(13) 0.5 June 7 8(47) 0 2 (12) 5(29) 2(12) 1.0 Totals 62 (60) 20 (19) 8 (8) 8 (8) 5 (5) 0.60 Temik May 7 2 (33) 4(67) 0 0 0 0.25 May 14 15(75) 3(15) 1(5) 0 1(5) 0.25 May 21 7(47) 6(40) 2(13) 0 0 0 May 27 20(61) 11(33) 2(6) 0 0 2.75 June 7 2(25) 0 4(50) 1(13) 1(13) 1.0 Totals 46 (56) 24(29) 9 (11) 1 (1) 2 (2) 0.85 Control May 7 30 (91) 2 (6) 0 0 1 (3) 0.25 May 14 32(89) 2(6) 2(6) 0 0 0.50 May 21 19(90) 1(5) 1(5) 0 0 10.5 May 27 20(56) 10(28) 4(11) 1(3) 1(3) 6.25 June 7 0 3 (38) 2 (25) 2 (25) 1 (13) 0.5 Totals 101 (75) 18 (13) 9 (7) 3 (2) 3 (2) 3.60 STobacco thrips (Frankliniella fusca), Western flower thrips (Frankliniella occidentalis), Flower thrips (Frankliniella la tritici), Soybean thrips (Neohydatothrips variabilis). Percent of totals in parentheses. ALABAMAAGRICULTURALExPERIMENT STATION14 1999 CorroN RESEARCH REPORT 15 Orthene treatment averaging somewhat more thrips than the other two insecticide treatments. The tobacco thrips, Frankliniellafusca, was the predomi- nant adult thrips in all treatments, but it occurred in large num- bers and at a higher percent in the control treatment than in other treatments (Table 1). This was likely due to early colonization, which provided a competitive advantage. The second most nu- merous species in all treatments was the Western flower thrips, F. occidentalis, although large numbers never occurred as has some- times happened when hot, dry conditions prevail in May and early June. Little difference was noted among treatments concerning the abundance of Western flower thrips although the Temik treat- ment contained the highest numbers and Admire the fewest. Flower thrips, F. tritici, and soybean thrips, Neohydatothrips variabilis, occurred in numbers too low to detect any particular treatment effects. A very few of the following adult thrips species were also present: F. exiqua, F. williamsi, and Thrips vulgatisima. All insecticide treatments contained fewer cotton aphids, on average, than did the control treatment. However, the control treat- ment contained fewer aphids at the end of the sample period than did other treatments. As indicated by bloom counts, all insecticide-treated plots bloomed earlier than the control treatment and the Admire and Temik treatments bloomed earlier than the Admire + Orthene treatment (Table 2). All insecticide treatments out-yielded the control, with the Temik and Admire treatments yielding the most. Overall, the Temik treatment outperformed other treatments, but considering the low rate, the Admire treatment was a close second. The Admire + Orthene treatment was less effective, but considerably better than the control. Some researchers have ob- served that imidacloprid treatments do not control Western flower thrips very well and that they control larval thrips better than they control adult thrips.Neither of these observations were confirmed in this study. TABLE 2. EFFECT OF INSECTICIDES ON BLOOM COUNT AND SEED COTTON YIELD Treatment July 6 July 7 July 8 July 9 Seasonal avg. Yield % Change -number of blooms/100 row feet lbs/ac from control Admire 86 89 101 105 95 3254 28.9 Temik 61 78 91 89 80 3270 29.5 Admire + Orthene 39 53 65 80 59 3156 25 Control 20 24 38 37 29 2525 - EVALUATION OF SELECTED SEED TREATMENTS AND IN-FURROW AND FOLIAR-APPLIED INSECTICIDES FOR THRIPS CONTROL IN COTTON Ron H. Smith The objective of this research was to evaluate selected seed treatments and in-furrow and foliar-applied insecticides for thrips control in cotton. TABLE 1. NUMBER OF THRIPS PER ROW FOOT AN Plots were planted on April at the Prattville Research Field 37 feet long with a 40-inch wi iD THRIP DAMAGE Treatment Rate May 27- -June 2 June 9 Thrips/foot Damage Thrips/foot Damage Damage Temik 15G 4.5 Ilbs/ac 0.50 c 1.50 d 0.33 a 1.17 b 1.33 b Temik 15G 8 Ibs/ac 1.17 c 2.00 cd 0.33 a 1.33 b 1.17 b Adage 5 FS 300g ai/100 kg 1.83 bc 2.17 cd 0.67 a 1.33 b 1.33 b Untreated - 1.83 bc 3.50 abc 1.33 a 3.00 ab 3.67 a Adage 5 FS 250g ai/100 kg 4.33 ab 3.50 abc 1.00 a 3.00 ab 2.33 ab Bidrin Overspray 0.25 Ib ai/ac 4.33 ab 5.00 a 1.33 a 5.00 a 4.17 a Adage 5 FS 200g ai/100 kg 4.67 bc 3.83 ab 1.00 a 3.17 ab 3.33 ab Gaucho 480 FS 250g ai/100 kg 4.83 a 3.17 bc 1.33 a 3.00 ab 2.67 ab Means within columns followed by a common letter are not significantly different at the p=0.05 level according to Duncan's Multiple Range Test. 123 with Deltapine DP 5415RR . Plots consisted of four rows ide row spacing and were ar- ranged in a completely ran- domized design with three replications. All plots were maintained throughout the season with standard herbi- cide, insecticide, and fertil- ity production practices as recommended by the Ala- bama Cooperative Exten- sion System. 1999 COTTON RESEARCHREPORT 15 16 ALABAMA AGRICULTURAL EXPERIMENT STATION Thrips were sampled when plants on one foot of row were beaten into a plas- tic pail. The sample site was selected at random from center two rows of four row plots. Thrips were counted on May 27 at the two true leaf stage, on June 9 at the eight true leaf stage, and on June 29 at the 12 to 14 leaf stage. A six- by 37-foot area of each plot was harvested on October 6. TABLE 2. PLANT HEIGHT AND NUMBER OF PLANTS PER ROW FOOT Treatment Rate May 27 June 2 June 9 June 9 Height (in) Height (in) Height (in) plants/ft Temik 15G 4.5 Ibs/ac 3.50 a 5.50 ab 9.33 a 3.33 ab Temik 15G 8 Ibs/ac 3.33 ab 5.33 ab 9.00 a 3.00 b Adage 5 FS 300g ai/100 kg 3.50 a 5.83 a 9.33 a 3.45 ab Untreated - 2.83 b 4.67 bc 5.67 b 4.11 a Adage 5 FS 250g a/V100 kg 3.33 ab 4.83 b 8.33 a 3.89 a Bidrin Overspray 0.25 Ib ail/ac 2.17 c 4.00 c 5.50 b 3.89 a Adage 5 FS 200g av100 kg 2.83 b 4.67 bc 5.67 b 4.00 a Gaucho 480 FS 250g ai/100 kg 3.17 ab 5.33 ab 8.00 ab 3.33 ab Means within columns followed by a common letter are not significantly different at the p=0.05 level according to Duncan's Multiple Range Test. Tobacco thrips was the primary species identified with a population of approximately 50% adults on June 2. Adage at 300 grams per 100 kilograms of seed gave statistically the same thrips control as Temik at 4.5 and 8.0 pounds active ingredi- ents per acre based on damage ratings at three dates (Table 1). This level of control was also supported by plant height counts made on the same dates (Table 2). Adage at the 200 and 250 gram rate was less effective than Temik. A Bidrin overspray was the least effective treatment, showing more damage and reduced plant height over the untreated. The node of first fruit- ing branch node and yields (Table 3) followed these same trends. TABLE 3. SEED COTTON PER ACRE Treatment Rate Seed cotton yield lbs/ac Temik 15G 4.5 lbs/ac 2452.7 ab Temik 15G 8 lbs/ac 2557.4 ab Adage 5 FS 300g ai/100 kg 2662.0 a Untreated 2315.4 ab Adage 5 FS 250g ai/1 00 kg 2400.4 ab Bidrin Overspray 0.25 lb ai/ac 1818.3 b Adage 5 FS 200g ai/100 kg 2178.0 ab Gaucho 480 FS 250g ai/100 kg 2335.0 ab Means within columns followed by a common letter are not significantly different at the p=0.05 level according to Duncan's Multiple Range Test. EVALUATION OF ORTHENE, TEMIK, AND ADMIRE FOR THRIPS CONTROL IN COTTON Ron H. Smith The objective of this research was to evaluate selected seed treatments and insecticide applications of Orthene, Temik, and Admire for thrips control in cotton. Plots were planted on April 20 with Deltapine NuCotn 35B at the Prattville Research Field. Plots consisted of four rows 30 feet long with a 40-inch wide row spacing and were arranged in a randomized complete block design with three replications. All plots were maintained throughout the season with standard herbi- cide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Insecticides were applied at-planting and as foliar sprays on May 12 and May 20. The sample site was selected at random from the center two rows of four-row plots. Thrips were sampled when plants on one foot of row were beaten into a plastic pail. Thrips were also mea- sured by visually observing and counting the number of thrips. Thrips were counted on May 11 (estimated 98% adult stage), June 9 (estimated 85% adult stage), and June 29 (estimated 70% adult stage). A six- by 37-foot area of each plot was harvested on Octo- ber 6. Damage ratings were made by observing the entire center two rows of each plot and assigning a number between 1 (ex- treme damage) and 5 (no visible thrips damage to foliage). No significant differences were present between treatments based on the number of thrips present per foot at the sample dates. However, on May 18 (Table 1) treatments consisting of Admire plus Orthene, Orthene plus CGA-215944, and the untreated con- trol had numerically much higher thrips numbers. Admire had the lowest damage rating on May 11 while Temik and Orthene ST + FS treatments showed less damage on May 18. On the last three sample dates-May 27, June 2, and June 9-all treatments had less damage than the untreated check. Plant height was in- versely related to the level of thrips damage on all sample dates (Table 2). There were numerical, but no statistical differences in yields between treatments (Table 3). ~( II 1 oramc n~r r I II I K1 I ~ar~m c nt rp.~n oavf? ctatr ctr r.s\ I Iv tnp. cam c? Tra+r~mat?~ 16 ALABAMAAGRICULTURALEXPERIMENT STATION TABLE 1. NUMBER OF THRIPS PER Row FOOT AND DAMAGE RATINGS 1 Treatment Rate -May 11- - May 18- - May 27- June 2 June 9 Thrips/foot Damage Thrips/foot Damage Thrips/foot Damage Damage Damage Temik 15 G 3.5 Ibs/ac 0.67 a 4.33 ab 3.33 a 3 b 1.67 a 1.83 c 1.17 b 1 b Orthene (S.T) + (S.T.) = 3.2 oz/ac 0.33 a 3.67 b 5.67 a 3.17 b 1 a 2.33 bc 1.33 b 1 b (F.S.) 97 PE Orthene (S.T.) + (S.T.) = 3.2 oz/ac 1 a 4.17 ab 4.67 a 4.33 ab 2.5 a 3.5 abc 2 b 1 b Regent 2.5 EC Admire 2 F (IF) 6.4 oz/ac 1 a 3.67 b 4.67 a 3.33 ab 2.83 a 3.5 abc 2.17 ab 1.83 Orthene (S.T.) + (S.T.) = 3.2 oz/ac 1 a 4.17 ab 7 a 3.67 ab 1.5 a 2.83 bc 1.67 b 1 b (F.S.) 90 SP Untreated - 1.33 a 4.67 a 12 a 4.67 a 4 a 4.83 a 4 a 2.83 a Admire 2 F(IF) +) 2.4 oz/ac + 0.55 lbs/ac 1.67 a 4.33 ab 13.67 a 4 ab 2.67 a 3.83 ab 3 ab 1.33 b Orthene 90 S (IF Orthene (S.T.) + (S.T.) = 3.2 oz/ac 1.33 a 4.0 ab 19 a 3.83 ab 2.33 a 2.83 bc 1.33 b 1 b CGA-215944 50 WP SDamage ratings on a scale of 1 - 5: 1 = no thrip damage on true leaves; 5 = heavy trip damage on true leaves. Means within columns followed by a common letter are not significantly different at the p--0.05 level according to Duncan's Multiple Range Test. TABLE 2. PLANT HEIGHT Treatment Rate May 18 May 27 June 2 June 9 in Temik 15 G 3.5 Ilbs/ac 4.3 a 6.83 a 9.33 a 15 a Orthene (S.T) + (F.S.) 97 PE (S.T.) = 3.2 oz/ac 3.83 abc 6 a 6 a 14.33 ab Orthene (S.T.) + Regent 2.5 EC (S.T.) = 3.2 oz/ac 3.73 abc 6.33 a 8.33 a 13.67 ab Admire 2 F (IF) 6.4 oz/ac 3.47 bc 6 a 8.5 a 12.67 ab Orthene (S.T.) + (F.S.) 90 SP (S.T.) = 3.2 oz/ac 4.13 ab 5.5 a 8.33 a 13.00 ab Untreated - 3.33 c 5.5 a 7.33 a 10.67 b Admire 2 F(IF) + 2.4 oz/ac + 0.55 lb/ac 3.70 abc 6.17 a 8.67 a 13.00 ab Orthene 90 S (IF) Orthene (S.T.) + (S.T.) = 3.2 oz/ac 3.93 abc 6.5a 8.67 a 13.67 ab CGA-215944 50 WP Means within columns followed by a common letter are not significantly different at the p=0.05 level according to Duncan's Multiple Range Test. TABLE 3. STAND DENSITY, BLOOMS, AND YIELD Treatment Rate Plants Blooms Seed cotton yield no/ft no/30 ft lbs/ac Temik 15 G 3.5 Ibs/ac 3.67 ab 14.00 a 3097.6 a Orthene (S.T) + (F.S.) 97 PE (S.T.) = 3.2 oz/ac 3.33 ab 9.00 ab 3057.3 a Orthene (S.T.) + Regent 2.5 EC (S.T.) = 3.2 oz/ac 3.11 b 7.00 b 3146.0 a Admire 2 F (IF) 6.4 oz/ac 3.33 ab 6.67 b 3041.1 a Orthene (S.T.) + (ES.) 90 SP (S.T.) = 3.2 oz/ac 3.11 b 7.00 b 3000.8 a Untreated - 3.56 ab 5.00 b 2694.3 a Admire 2 F(IF) + 2.4 oz/A + 0.55 lb/ac 3.78 a 5.67 b 2815.3 a Orthene 90 S (IF) Orthene (S.T.) + (S.T.) = 3.2 oz/ac 3.45 ab 7.33 b 3025.0 a CGA-215944 50 WP Means within columns followed by a common letter are not significantly different at the p=0.05 level according to Duncan's Multiple Range Test. 1999 COTTON RESEARCHREPORT 17 ALABAMA AGRICULTURAL EXPERIMENT STATION THE EFFECT OF SELECTED INSECTICIDES ON THE TARNISiED PLANT BUG AND BENEFICIAL ARTHROPODS IN DP Barry L. Freeman The objective of this research was to evaluate several insec- ticide treatments for their effect on tarnished plant bug and com- mon beneficial arthropods. Plots were established on April 12 with Deltapine DP 20B at the Tennessee Valley Research and Extension Center in Belle Mina, Alabama. Plots consisted of eight rows, 300 feet long with a 40-inch wide row spacing. Plots were maintained according to Alabama Cooperative Extension System recommendations for weed control and fertility. Insecticide applications were made on June 16 and July 14. Ten, six-foot drop cloth samples were taken and 100 pin- head squares were inspected for plant bug damage in whole-field, pretreatment samples. Posttreatment samples consisted of four, three-foot drop cloth samples at first evaluation and four, six-foot drop cloth samples thereafter. Forty pinhead squares per plot were sampled to determine the level of plant bug damage on June 21, June 25, July 1, and July 20. Forty white blooms per plot were inspected for plant bug 20B CoroIN N NRTH ALABAMA damage on July 20 and 28 while 40 young bolls per plot were inspected for plant bug damage on July 28. The trial began just as beneficial arthropods and plant bugs were becoming established in cotton. Numbers of both were moderate and some reproduction had begun (Table 1).The fairly high plant bug damage level reported in Table 1 appears to indi- cate that the number of adult plant bugs was higher than indi- cated by the sample taken. This discrepancy could be caused by the fact that the drop cloth is a poor technique for sampling adult plant bugs. The following arthropods were sampled: big-eyed bugs, insidious flower bugs, damsel bugs, lady beetles, lace wings, spi- ders, ants, and tarnished plant bugs. Adults and immatures were noted except in the case of spiders and ants (Table 2). Tracer had little impact on the overall beneficial complex and consistently had more big-eyed bugs than did the control plot. Steward had a very mild impact on most beneficial species, especially on flower and damsel bugs. Although there tended to TABLE 1. NUMBER OF PLANT BUGS AND PERCENT PINHEAD SQUARE RETENTION, BLOOM DAMAGE, AND BOLL DAMAGE PER 100 Row FEET - June 21 - June 25 --------July 1 Treatment Adult Nymph Square Adult Nymph Square Adult Nymph Square retention retention retention Karate 0 8.3 85 4.2 20.7 83 0 33.3 83 Orthene 8.3 41.6 70 0 62.3 73 0 120.4 83 Steward 0.065 8.3 66.0 80 8.3 16.2 55 8.3 120.4 70 Steward 0.11 8.3 100.0 78 0 103.8 70 4.2 137.0 50 Steward 0.05 0 117.0 58 0 137.0 58 0 120.4 55 Steward 0.055 0 58.2 60 8.3 154.0 55 16.6 187.0 43 Tracer 0.063 8.3 150.0 60 4.2 170.2 53 4.2 186.8 45 Control 16.7 266.4 58 0 95.5 63 8.3 174.3 48 TABLE 1, CONTINUED. NUMBER OF PLANT BUGS PERCENT PINHEAD SQUARE RETENTION, BLOOM DAMAGE, AND BOLL DAMAGE PER 100 Row FEET July 20 July 28 - Seasonal Averago Treatment Adult Nymph Square BLB 1 Adult Nymph BD 2 BLD Adult Nymph Total Change 3 Square retention % retention Karate 0 12.5 57.5 42.5 8.3 0 0 25.0 2.5 15.0 17.5 -88.2 77.1 Orthene 0 45.8 25.0 25. 0 45.8 5.0 32.5 1.7 63.2 64.9 -56.4 68.4 Steward 0.065 0 75.0 25.0 25.0 0 70.8 2.5 37.5 5.0 89.7 94.7 -36.4 63.1 Steward 0.11 4.2 50.0 12.5 12.5 4.2 62.5 2.5 37.5 4.2 90.7 94.9 -36.3 59.5 Steward 0.05 8.3 108.3 22.5 22.5 4.2 66.7 2.5 55.0 2.5 109.9 112.4 -24.5 54.0 Steward 0.055 12.5 104.2 30.0 30.0 4.2 70.8 10.0 45.0 8.3 114.8 123.1 -17.3 50.1 Tracer 0.063 8.3 87.5 30.0 30.0 12.5 62.5 12.5 45.0 7.5 131.4 138.9 -6.7 47.6 Control 8.3 108.3 37.5 37.5 4.2 62.5 15.0 47.5 7.5 141.4 148.9 - 52.9 1 BLD = Bloom damage; 2 BD = Boll damage. 3 Percent change in total plant bug numbers from control. 18 1999 CorroN RESEARCH REPORT 19 be a positive rate response between the two lower and two higher rates of Steward, an overall strong rate response was not evident. Orthene and Karate significantly reduced overall predator com- plex with Karate being generally a little harsher than Orthene. Orthene and Karate provided the best plant bug control with Ka- rate being superior to Orthene. Steward did reduce plant bug num- bers and damage as compared to a control plot, but the reduction was modest. Tracer had no measurable impact on plant bugs. The selectivity by Steward for predaceous arthropods mea- sured in this study should prove very useful in cotton pest man- agement programs. It is questionable as to what use can be made of the plant bug suppression demonstrated by Steward in areas with substantial populations. As expected, Tracer's selectivity toward beneficials was once again confirmed, and Tracer's lack of plant bug control was also expected. TABLE 2. SEASONAL AVERAGE OF ALL PREDATORS PER 100 FEET OF Row Treatment Tracer 0.063 Control Steward 0.065 Steward 0.055 Steward 0.11 Steward 0.09 Orthene Karate Total number of predators 453.0 451.0 417.0 401.9 389.2 367.0 215.0 177.1 % Change from control 0 -7.5 - 11.0 - 14.0 - 19.0 - 52.0 -61.0 THE EFFECT OF SELECTED INSECTICIDES ON THE TARNISHED PLANT BUG AND BENEFICIAL ARTHROPODS IN SURE-GROW 125BR COTTON IN NORTH ALABAMA Barry L. Freeman The tarnished plant bug has been a significant problem for cotton producers in North Alabama for many years. Since the boll weevil has been largely removed and Bt cotton has been widely adopted, foliar sprays for cotton insect control have been dramatically reduced. The removal of this incidental control of the tarnished plant bug has further increased this insect's status as a pest of cotton. Many people now regard the tarnished plant bug as the leading insect threat to cotton production in North Ala- bama and other areas. This reduction in foliar sprays has also fostered beneficial organisms. The ability to utilize parasites and predators in a cot- ton insect management program is greater than it has ever been, but tarnished plant bug control can severely retard the use of this desirable management tool. As a result, it is important to evaluate an insecticide's effect on beneficial organisms as well as the tar- get insects. This trial was designed to evaluate 13 treatments for their effect on tarnished plant bug and beneficial arthropod popula- tions. Seven treatments involved unregistered compounds. Plots were established on April 12 with Sure-Grow 125BR cotton at the Tennessee Valley Research and Extension Center in Bell Mina, Alabama. Plots consisted of eight rows 200 feet long TABLE 1. NUMBERS OF TARNISHED PLANT BUGS PER 100 FEET OF Row Treatment June 21 June 23 June 29 July 19 July 27 Seasonal average Change 4 A 1 N 2 A N A N A N A N A N T 3 % Orthene 0 16.6 0 29.0 0 21.0 0 8.3 4.2 0 0.8 15.0 15.8 - 89 Regent (.05) 0 8.3 0 4.2 4.2 4.2 0 4.2 12.5 58.3 3.3 15.8 19.1 - 87 Bidrin 0 0 4.2 49.8 12.5 41.4 0 0 0 41.7 3.3 26.6 29.9 - 80 Actara (.062) 8.3 16.6 0 29.1 0 77.5 0 20.8 4.2 33.3 2.5 35.5 38.0 - 74 Karate 0 8.3 4.2 4.2 0 0 0 54.2 8.3 141.7 2.5 41.7 44.2 - 70 Vydate 8.3 41.3 0 16.6 4.2 33.0 12.5 62.5 8.3 54.2 6.7 41.5 48.2 - 67 Regent (.038) 8.3 16.6 12.5 29.1 0 83.0 1 16.7 4.2 87.5 5.8 46.6 51.6 -65 Steward (.11) 0 49.5 0 49.5 8.3 87.2 4.2 20.8 4.2 58.3 3.3 53.1 56.4 - 62 Actara (.05) 8.3 24.8 0 45.7 4.2 45.7 0 70.8 4.2 87.5 3.3 54.9 58.2 - 60 Provado 8.3 8.3 16.5 16.6 4.2 87.3 4.2 45.7 4.2 129.2 7.59 57.4 64.9 - 56 Steward + Vydate 0 33.0 8.3 74.7 0 83.1 0 12.5 0 41.7 1.7 71.5 73.2 - 50 Steward (.09) 8.3 57.8 4.2 83.0 8.3 190.8 0 16.7 4.2 45.7 5.0 78.8 83.8 - 43 Control 8.3 239.3 0 153.8 8.3 199.3 8.3 75.0 0 41.7 5.0 141.8 146.8 - 14 1 A=adult. 2 N=nymph. T=total. 4 Percent change in total plant-bug numbers from control. ~rv~) vwr ~rrv rvuuvrrvrr I .~n~T~I I II~ ~C~IC~~LI V ILV U Y I~L~W CU U 1VI UI~UU~~VU3 CU LIIIVVVU3 I1I~U- VLvrr~lu v vuu 1999 COTTON RESEARCHREPORT 19 20 ALABAMA AGRICULTURAL EXPERIMENT STATION and were not replicated. Insecticides were applied on June 16 and July 14. Forty-eight hour pretreatment samples revealed 78 plant bugs and 173 total predators per 100 feet of row. All treatments re- duced plant bug numbers considerably. The best treatments over- all were Orthene, the high rate of Regent, and the Bidrin treat- ment, all of which provided 80% control or better (Table 1). Ka- rate was as good or better than any treatment after the first appli- cation, but significant numbers of nymphs were present on the two sample dates after the second application (Table 1). Karate and most other pyrethroids have been very effective plant bug control agents during the past several seasons and this has been particularly true in dealing with imbedded July populations. These data could indicate a pyrethroid resistance problem in the tar- nished plant bug though no on-farm problems were encountered during 1999 or in previous years. Ofthe predaceous arthropods sampled in this study, the hemi- pteran predators are the most important. Big-eyed bugs, flower bugs, and damsel bugs all prey upon important caterpillar pests of cotton and are critical to insect management programs. Lady beetles and lacewings tend to key upon aphid populations and are only secondarily important as enemies of caterpillars. Spiders are catholic in their taste and their status as an important predator in cotton is dubious. The treatment impact on big-eyed bugs was varied (Table 2). Steward, Vydate, and combinations thereof had an overall posi- tive impact on these bugs and the low rate of Actara had a very modest negative impact (Table 2). With the exception ofProvado the other treatments had a relatively serious negative impact on this predator (Table 2). Provado's impact was in between the first and second group of treatments (Table 2). Regent had a particu- larly negative impact on big-eyed bugs. The impact on flower bugs by most treatments was fairly severe. Regent was a notable exception, possessing populations considerably higher than in the control treatment. The impact on flower bugs by the Bidrin treat- ment and one of the Steward treatments was not as great as other treatments. Regent's apparent selectivity for insidious flower bugs has been observed with consistency in previous trials. However, the overall data from this trial may indicate a competitive ad- vantage of big-eyed bugs over flower bugs, and the seemingly positive impact of Regent on flower bug populations may be a simple reflection of the compounds efficacy against big-eyed bugs. Damsel bug populations were affected the least by the Stew- ard, Vydate, and low rate of Actara treatments. Even though good numbers of damsel bugs occurred during this trial, the relative scarcity of this predator makes it difficult to draw firm conclu- sions from one test. Lady beetle populations were reduced by 20 TABLE 2. NUMBER OF BIG-EYED BUGS PER 100 FEET OF Row Treatment June 21 June 23 June 29 July 19 July 27 Seasonal average Change A 1 N 2 A N A N A N A N A N T %4 Vydate 8.3 8.3 6.6 29.0 20.7 116.2 54.2 358.3 91.7 341.7 36.3 170.7 207.0 22.5 Steward (.09) 49.5 8.3 33.2 54.1 8.3 137.0 20.8 250.0 83.3 337.5 39.0 157.4 196.4 16.2 Steward + Vydate 0 0 4.2 62.3 8.3 87.3 37.5 179.2 87.5 470.1 27.5 159.8 187.3 10.8 Steward (.11) 8.3 0 16.6 37.2 29.2 124.6 29.2 258.3 54.2 375.0 27.5 159.0 186.5 10.4 Control 16.5 0 24.9 45.6 12.4 120.4 25.0 329.2 29.2 241.7 21.6 147.4 169.0 - Actara (0.05) 8.3 0 12.5 20.7 20.7 83.2 20.8 166.7 50.0 362.5 22.5 126.6 149.1 - 11.8 Provado 24.8 0 33.2 4.2 12.4 125.0 29.2 141.7 58.3 204.2 31.6 95.0 126.6 - 25.1 Actara (.062) 24.8 0 16.6 8.3 4.2 108.3 12.5 75.0 29.2 225.0 17.5 83.3 100.8 - 40.4 Bidrin 0 0 24.8 24.8 16.6 53.9 33.3 91.7 25.0 204.2 19.9 74.9 94.8 - 43.9 Orthene 0 0 4.2 4.2 8.3 62.0 8.3 104.2 75.0 120.8 19.2 58.2 77.4 - 54.2 Karate 8.3 0 4.2 4.2 12.4 29.2 0 33.3 16.7 175.0 8.3 48.3 56.6 - 66.5 Regent (0.38) 0 8.3 4.2 0 0 53.9 4.2 0 4.2 4.2 2.5 13.3 15.8 - 90.7 Regent (0.05) 0 0 20.7 0 0 41.6 0 0 8.3 4.2 5.8 9.2 15.0 - 91.1 SA=adult. 2 N=nymph. 3 T=total. 4 Percent change in total big-eyed bug numbers from control. ALAE3AMAAGRICULTURAL'EXPERIMENT STATION20 1999 COTTON RESEARCH REPORT 21 to 73%, as compared to the control treatment, by all treatments except for the Karate and Orthene treatments. Aphid populations were observed to be higher in the Karate, Orthene, and Vydate plots, which is likely more responsible for the increase in lady beetles than is efficacy. Overall lacewing populations were sig- nificantly reduced by all treatments. Spider populations were re- duced by all treatments, but Actara, the low rate ofRegent, Vydate, and one of the Steward treatments had the least effect. In general the Steward and Vydate treatments had the least impact on the important hemipteran predators while Orthene and Karate had the greatest impact (Table 3). In conclusion, the performance of Karate on plant bugs af- ter the second application is of concern, but concluding problems with pyrethroid resistance in the tarnished plant bug in north Ala- bama would be premature. In addition, a greater rate response was noted with Regent than in most previous trials. Finally, prod- ucts which provide good plant bug control tend to have the great- est negative impact against predaceous arthropod populations. TABLE 3. SEASONAL AVERAGE OF ALL HEMIPTERAN PREDATORS Treatment -Seasonal average- Change' Adult Nymph Total % Vydate 57.2 196.5 253.7 2.3 Steward (0.11) 59.0 193.4 252.4 1.8 Control 63.0 184.9 247.9 - Steward (0.09) 66.4 177.4 243.8 - 1.7 Steward + Vydate 46.6 188.1 234.7 - 5.3 Actara (0.05) 46.6 137.4 184.0 - 25.8 Bidrin 66.4 103.2 169.6 - 31.6 Provado 48.9 110.8 159.7 - 35.6 Regent (0.38) 60.5 95.8 156.3 - 37.0 Actara (0.062) 30.0 89.1 119.1 - 52.0 Regent (0.05) 43.2 73.3 116.5 - 53.0 Karate 25.0 68.3 93.3 - 62.4 Orthene 30.1 59.0 89.1 - 64.1 SPercent change in total plant bug numbers from control. THE EFFECT OF SELECTED INSECTICIDES ON THE TARNISHED PLANT BUG AND BENEFICIAL SPECIES IN SURE-GROW 180 COTTON IN CENTRAL ALABAMA Ron H. Smith and Richard L. Davis The objective of this research was to evaluate selected fo- liar-applied insecticides for tarnished plant bug control and selec- tivity on beneficial insects in cotton. Plots were planted on April 13 with Sure-Grow 180 at the Prattville Research Field. Plots consisted of eight-rows 120 feet long with a 40-inch wide row spacing and were arranged as adja- cent strips with one replicate (screening trial with sub-samples taken within each treatment). All plots were maintained through- out the season with standard herbicide and fertility production practices as recommended by the Alabama Cooperative Exten- sion System. Treatments were applied on June 22 (treatment number one) and July 7 (treatment number two). Plant size at initial treatment was approximately 26 to 28 inches (second week of bloom). Sam- pling methods varied depending on growth stage of the plant. Evaluation on June 24 was made with a sweep net held horizon- tally. Plants were beaten into a net at 10 row feet per sample. On June 29 and July 8, a drop cloth was used to sample an area of four row feet. Square retention was validated by examining the top two fruiting sites on 20 plants per treatment for a total of 40 fruiting sites. Evaluations were made on June 24 (two days after treat- ment number one), June 29 (seven days after treatment number one) and July 8 (two days after treatment number two). The ma- jority of plant bug population on June 22 (treatment number one) were adults while the population had shifted to immatures on July 7 (treatment number two). A six- by 37-foot area of each plot was harvested on October 6. The number of adult tarnished plant bugs was well above threshold and the square retention was severely depressed (55%) when this test was initiated on June 24 (Table 1). All treatments gave significant control of adult plant bugs at one-day post treat- ment. However, there was a wide range of improvement in per- cent square set from a low of 54% with Acetamiprid 0.075 to a high of 83% with Bidrin 41WP at 0.25. Acetamiprid at 0.025 and 0.038 showed the most selectivity toward big-eyed bugs (Table 2), but less selectivity toward minute pirate bugs (Table 3). Pirate at 0.35 showed the most selectivity toward minute pirate bugs followed by Lorsban at 0.2. At seven days posttreatment (June 29) the majority of the plant bug population was immatures. This evaluation likely was the best measure of residual control by the various treatments. WI~ rrl~CILC~3L IlIIUCLI~L r laul~ J ~. -- \- - -r 1999 COTTON RESEARCHREPORT 21 22 ALABAMA AGRICULTURAL EXPERIMENT STATION Bidrin 41 WP gave the greatest residual control with the three rates of Acetamiprid giving moderate control. The least residual con- trol was obtained from Orthene, Decis, and Leverage. At seven days posttreatment, the greatest selectivity toward big-eyed bugs was found in the Acetamiprid 0.025 treatment. However, again this was not the case with minute pirate bugs since all treatments reduced this species below the untreated after seven days. Most treatments had resulted in improved square retention (over 80%) after seven days. Treatment number two was targeted to a predominant nymphal population of plant bugs on July 6. At two days post- treatment, all treatments significantly reduced plant bugs below the untreated check. In general, the pyrethroid treatments and Bidrin 8EC gave the greatest reduction. Steward, Acetamiprid, and Bidrin 41WP followed with moderate to good suppression. Again, Acetamiprid and Provado showed the greatest selectivity toward big-eyed bugs but not minute pirate bugs. All treatments raised square retention to well above 80% after application num- ber two. When all three sample dates were combined, Bidrin 41WP, Capture, and Karate gave the best plant bug suppression. The least suppression was found behind Orthene, Decis, Leverage, Pirate, and Provado. Steward, Lorsban, Bidrin 4EC, and the three rates of Acetamiprid were in the middle group as far as tarnished plant bug suppression was concemrned. There were no rate responses toward tarnished plant bugs with the three rates of Acetamiprid. However, Acetamiprid showed the most selectivity of all treat- ments to big-eyed bugs and there was a rate relationship with this species. Pirate, Provado, and Steward showed the most selectiv- ity toward minute priate bugs species. TABLE 1. NUMBER OF TARNISHED PLANT BUGS PER 100 Row FEET Treatment Rate ---- June 24 ----- June 29- --- July 8- -Season lbs ailac N' A 2 T 3 N A T N A T N A T Bidrin 41WP 0.25 0 0 0 37.5 0 37.5 25 6.25 31.25 20.83 2.08 22.92 Capture 2 EC 0.04 0 0 0 81.25 0 81.25 12.5 0 12.5 1.25 0.00 31.25 Karate 2 EC 0.025 0 0 0 75 6.25 81.25 18.75 0 18.75 31.25 2.08 33.33 Bidrin 8 EC 0.25 0 3.33 3.33 112.5 18.75 131.25 12.5 0 12.5 41.67 7.36 49.03 Lorsban 4 EC 0.2 6.67 10 16.67 93.75 0 93.75 25 12.5 37.5 41.81 7.50 49.31 Acetamiprid 70 WP 0.038 3.33 6.67 10 106.25 12.5 118.75 25 0 25 44.86 6.39 51.25 Acetamiprid 70 WP 0.025 0 0 0 125 6.25 131.25 25 6.25 31.25 50.00 4.17 54.17 Acetamiprid 70WP 0.075 0 0 0 100 0 100 62.5 0 62.5 54.17 0.00 54.17 Steward 1.25 SC 0.11 3.33 0 3.33 143.75 0 143.75 18.75 6.25 25 55.28 2.08 57.36 Provado 1.6 F 0.047 3.33 6.67 10 137.5 0 137.5 56.25 0 56.25 65.69 2.22 67.92 Pirate 3 SC 0.35 6.67 0 6.67 14.75 0 143.75 87.5 0 87.5 79.31 0.00 79.31 Leverage 2.7 3 ozlac 0 3.33 3.33 193.75 6.25 200 43.75 0 43.75 79.17 3.19 82.36 Decis 1.5 EC 0.019 6.67 0 6.67 275 0 275 31.25 0 31.25 104.31 0.00 104.31 Orthene 90 SP 0.225 0 6.67 6.67 281.25 0 281.25 43.75 12.5 56.25 108.33 6.39 114.72 Untreated - 3.33 23.33 26.66 243.75 6.25 250 175 0 175 140.69 9.86 150.55 'N=nymphs. 2 A= adults. 3 T = total. Pretreatment populations on June 21 averaged 15 nymphs and 22.5 adults. ALABAMAAGRICULTURALExPERIMENT STATION22 TABLE 2. NUMBER OF BIG-EYED BUGS PER 100 Row FEET Treatment Rate -June 24- -June 29- --- July 8- -Season- Ibs ai/ac N 1 A 2 P3 N A T N A T N A T Acetamiprid 70 WP 0.025 6.67 20 26.67 81.25 31.25 112.5 18.75 37.5 56.25 35.56 29.58 65.14 Acetamiprid 70 WP 0.038 6.67 33.33 40 62.5 0 62.5 25 31.25 56.25 31.39 25.53 52.92 Steward 1.25 SC 0.11 0 13.33 13.33 37.5 37.5 75.0 12.5 0 12.5 16.67 16.94 33.61 Acetamiprid 70 WP 0.075 0 9 9 12.5 12.5 25 18.75 43.75 62.5 10.42 21.75 32.17 Untreated - 6.67 20 26.67 37.5 12.5 50 18.75 0 18.75 20.97 10.83 31.81 Provado 1.6 F 0.047 0 6.67 6.67 25 0 25 12.5 43.75 56.25 12.50 16.81 29.31 Lorsban 4 EC 0.2 0 20 20 12.5 0 12.5 0 50 50 4.17 23.33 27.50 Pirate 3 SC 0.35 3.33 10 13.33 0 37.5 37.5 0 6.25 6.25 1.11 17.92 19.03 Orthene 90 SP 0.225 3.33 3.33 6.66 6.25 6.25 12.5 6.25 18.75 25 5.28 9.44 14.72 Leverage 2.7 3 oz/ac 0 0 0 12.5 6.25 18.75 0 18.75 18.75 4.17 8.33 12.50 Decis 1.5 EC 0.019 0 0 0 18.75 6.25 25 6.25 0 6.25 8.33 2.08 10.42 Bidrin 8 EC 0.25 0 0 0 6.25 6.25 12.5 0 12.5 12.5 2.08 6.25 8.33 Capture 2 EC 0.04 0 0 0 0 0 0 12.5 0 12.5 4.17 0.00 4.17 Karate Z 2.08 0.025 0 0 0 0 6.25 6.25 0 6.25 6.25 0.00 4.17 4.17 Bidrin 41 WP 0.25 0 0 0 0 0 0 6.25 0 6.25 2.08 0.00 2.08 N = nymphs. 2 A = adults. 3 T = total. Pretreatment populations on June 21 averaged 0 nymphs and 20 adults. TABLE 3. NUMBER OF MINUTE PIRATE BUGS PER 100 Row FEET Treatment Rate --- June 24-- -- June 29- -July 8-Season Ibs ai/ac N 1 A 2 T 3 N A T N A T N A T Untreated - 0 46.67 46.67 6.25 50 56.25 12.5 37.5 50 6.25 44.72 50.97 Pirate 3 SC 0.35 0 40 40 0 25 25 0 12.5 12.5 0.00 25.83 25.83 Provado 1.6 F 0.047 6.67 6.67 13.34 12.5 31.25 43.75 0 6.25 6.25 6.39 14.72 21.11 Steward 1.25 SC 0.10 0 16.67 16.67 0 31.25 31.25 0 12.5 12.5 0.00 20.14 20.14 Orthene 90 SP 0.225 0 16.67 16.67 0 37.5 37.5 0 0 0 0.00 18.06 18.06 Capture 2 EC 0.04 0 3.33 3.33 0 43.75 43.75 0 0 0 0.00 15.69 15.69 Leverage 2.7 3 oz/ac 0 3.33 3.33 0 31.25 31.25 0 12.5 12.5 0.00 15.69 15.69 Bidrin 8 EC 0.25 0 6.67 6.67 0 37.5 37.5 0 0 0 0.00 14.72 14.72 Acetamiprid 70 WP 0.025 0 6.67 6.67 0 25 25 6.25 0 6.25 2.086 10.56 12.64 Lorsban 4 EC 0.2 0 23.33 23.33 0 12.5 12.5 0 0 0 0.00 11.94 11.94 Decis 1.5 EC 0.019 0 0 0 0 18.75 18.75 0 6.25 6.25 0.00 8.33 8.33 Karate Z 2.08 0.025 0 0 0 0 18.75 18.75 0 6.25 6.25 0.00 8.33 8.33 Acetamiprid 70 WP 0.075 0 3.33 3.33 0 12.5 12.5 0 6.25 6.25 0.00 7.36 7.36 Acetamiprid 70 WP 0.038 0 0 0 0 18.75 18.75 0 0 0 0.00 6.25 6.25 Bidrin 41 WP 0.25 0 0 0 6.25 0 6.25 0 6.25 6.25 2.08 2.08 4.17 1 N = nymphs. 2 A = adults. 3 T = total. Pretreatment populations on June 21 averaged 0 nymphs and 97.5 adults. 1999 COTTON RESEARCHREPORT 23 24 ALABAMA AGRICULTURAL EXPERIMENT STATION EFFICACY OF SELECTED INSECTICIDES FOR BOLLWORM/BUDWORM CONTROL IN COTTON Ron H. Smith and Richard L. Davis The objective of this research was to evaluate selected fo- liar-applied insecticides for bollworm/budworm control in cotton. Plots were planted on April 12 with Sure-Grow 180 cotton on the Prattville Research Field. Plots consisted of four rows 60 feet long with a 40-inch row spacing and were arranged in a ran- domized complete block with four replications. All plots were maintained throughout the season with standard herbicide and fertility production practices as recommended by the Alabama Cooperative Extension System. Insecticides were applied on June 18, July 16, July 19, Au- gust 3, and August 13. The insecticides applied on July 16 were washed off by rain. Plots were evaluated on June 21, July 26, August 6, and August 17. Whole plant surveys were taken on seven plants selected at random from the center two rows of each plot. Subsampling consisted of examining 20 additional squares per plot for bollworm/budworm damage. Species identified were tobacco budworms (nearly 100%) on June 18, cotton bollworm (more than 90%) on July 16 and 19, and tobacco budworms (estimated at 70%) on August 3 and 13. The center two rows of each 60-foot plot were harvested on Sep- tember 23. All treatments reduced the number of bollworm/budworm larvae below the untreated check (Table 1). Intrepid plus Karate was the most effective treatment while Dimilin and Denim were the least effective. Damaged fruit ratings were closely related to the level of worm control. In general, the treatments with pyre- throid chemistry were as effective or more so than the newer chem- istry. This indicates that the bollworm species made up the majority of the worm population in 1999. Yields ranged from a high of 2,395 pounds per acre to a low of 2,072 pounds per acre (Table 2). TABLE 1. NUMBER OF LARVAE LARGER THAN 0.25 INCH PER 100 PLANTS AND PERCENT SQUARE DAMAGE Treatment' Rate June 21 July 26 August 6 August 17 Season lbs ai/ac Larvae Damage Larvae Damage Larvae Damage Larvae Damage Larvae Damage Intrepid 80 WP + 0.15 + 0.033 0 a 3.33 a 8 b 1.25 d 0 a 0 c 0 b 5 a 0 c 2.4 c Karate Z Karate Z 0.033 0 a 0 a 3.5 b 2.5 cd 0 a 3.75 bc 0 b 2.5 a 0.88 bc 2.19 c Orthene 90 Sp + 0.5+ 0.025 0 a 8.33 a 3.5 b 5 cd 0 a 0 c 3.5 b 8.75 a 1.75 bc 5.42 c Decis 1.5 EC Steward 1.25 SC 0.11 0 a 5 a 0 b 3.75 cd 0 a 3.75 bc 7 b 5 a 1.75 bc 4.17 c Tracer 4 SC 0.062 0 a 5 a 3.5 b 7.5 cd 3.5 a 7.5 ab 0 b 2.5 a 1.75 bc 5.52 c Decis 1.5 EC 0.025 0 a 3.33 a 3.5 b 3.75 cd 3.5 a 3.75 bc 3.5 b 5 a 2.63 bc 4.27 c Fury 1.5 EC + 0.0375+ 0.3 0 a 6.67 a 7 b 5 cd 3.5 a 2.5 bc 0 b 2.5 a 2.63 bc 3.85 c Lepinox Steward 1.25 SC 0.09 0 a 0 a 3.5 b 6.25 cd 0 a 0 c 7 b 11.25 a 2.63 bc 4.79 c Dimilin 2L 6.0 oz 0 a 10 a 10.5 b 15 b 7 a 11.25 a 3.5 b 6.25 a 5.25 bc 10.52ab Denim 0.16 EC 0.01 2.5 a 6.67 a 6.67 b 10 bc 7 a 2.5 bc 7 b 10 a 5.88 b 7.08 bc Untreated - 0 a 10a 10a 23.75 a 7 a 7.5 ab 17.5a 8.75 a 14.13a 12.4 a 'Treatments made June 18, July 19, August 3, and August 13. Means within columns followed by a common letter are not signifi- cantly different at the p=0.05 level according to Duncan's Multiple Range Test. TABLE 2. SEED COTTON YIELD PER ACRE Treatment Rate Seed cotton Treatment Rate Seed cotton yield yield lbs ai/ac lbs/ac lbs ai/ac lbs/ac Intrepid 80 WP + Karate Z 0.15 + 0.033 2395.8 a Fury 1.5 EC + Lepinox 0.0375 + 0.3 2323.2 ab Karate Z 0.033 2329.3 ab Steward 1.25 SC 0.09 2320.2 ab Orthene 90 Sp + Decis 1.5 EC 0.5 + 0.025 2492.6 a Dimilin 2L 6.0 oz 2084.2 b Steward 1.25 SC 0.11 2283.9 ab Denim 0.16 EC 0.01 2259.7 ab Tracer 4 SC 0.062 2072.1 b Untreated - 2072.1 b Decis 1.5 EC 0.025 2329.3 ab Means within columns followed by a common letter are not significantly different at the p=0.05 level according to Duncan's Multiple Range Test. 24 ALABAMAAGRICULTURALExPERIMENT STATION RESISTANCE MONITORING OF TOBACCO BUDWORM/COTTON BOLLWORM IN BT COTTON William J. Moar and Ron H. Smith Since the introduction of Bt cotton in the United States in 1996, Alabama growers have consistently used Bt cotton in about 65% of the statewide cotton acreage. This is the highest percent- age use of Bt cotton in the United States. Furthermore, several areas of the state such as southwestern Alabama, have used the 96/4 strategywith Bt cotton on most farms for the last four years. Although concerns have always been raised regarding the in- creased threat of Bt resistance developing in insects exposed to Bt transgenic crops, this "concentrated" use of Bt cotton should raise these concerns even higher. To help address some of the concerns regarding Bt resistance developing in tobacco budworm and cotton bollworm, the U.S. De- partment ofAgriculture's Agricultural Research Service (USDA/ARS) facility in Stoneville, Mississippi, started providing insect larval bio- assay services in 1997 for anyone willing to send them tobacco bud- worm or cotton bollworm from Bt cotton areas. In 1997, growers, consultants, and extension and university faculty from Alabama sent in a total of 23 samples of insects for resistance assessment. These samples were collected from throughout Alabama and represented about 40% of all insect samples received and tested by USDA/ARS. This project has continued annually since 1997. This summary re- ports the results from the 1999 growing season. About 70 Bt Resistance Management Kits were sent out to interested parties (consultants, extension specialists, private in- dustry), primarily in the southern half Alabama and northwestern Florida. Most of these kits were not used because ofthe relatively low numbers of tobacco budworms and cotton bollworms found in Bt and nonBt cotton. However, at least 10 tobacco budworm/ cotton bollworm samples from Alabama were sent to USDA/ARS in Stoneville. These samples came primarily from Autauga, Escambia, Henry, and Mobile counties and accounted for about 20% of all samples analyzed by USDA/ARS in 1999. These samples were tested for Bt resistance, which is indicated by the insects' susceptibility to Heliothis virescens and Helicoverpa zea. Results from these tests showed no detectable changes in susceptibility for H. virescens. After four years of sometimes in- tense use of Bt cotton, the level of susceptibility in H. virescens has not changed. Results with H. zea from 1999, however, showed a significant decrease in susceptibility in one population from Mobile County, Alabama, and one population in Escambia County, Florida. However, this change in susceptibility was not a reduction in mortality; it was just an increase in the number of larvae that required several more days to die than normal. These results show a trend in decreased susceptibility for H. zea. As such, the monitoring program needs to be maintained or perhaps even increased in order to further document the current observa- tions and to determine if these trends will, in fact, continue. How- ever, our results by do not appear to be substantial or conclusive enough to suggest that an increase in refugia (areas where Bt cot- ton is not planted) is warranted. EVALUATION OF SELECTED INSECTICIDES FOR EFFICACY ON SOYBEAN LOOPERS Ron H. Smith and Richard L. Davis The objective of this research was to evaluate foliar-applied insecticides for soybean looper control in cotton. Plots were planted on May 20 with Deltapine DP 458BRR cotton on the Little Farm in Baldwin County, Alabama. Plots con- sisted of four rows 500 feet long and 36 inches wide and were arranged as adjacent strips with one replication (screening trial). All plots were maintained throughout the season with standard herbicide and fertility production practices as recommended by the Alabama Cooperative Extension System. Treatments were applied on August 28. Plots were evaluated for soybean loopers on September 1 and September 23. Four sample sites were selected at random from the center two rows within each strip. At each site, six row feet were sampled by the shake cloth method. Foliage loss was estimated after the entire treated area was surveyed (Table 1). TABLE 1. PERCENT DEFOLIATION ON SEPTEMBER 23 Treatment Rate - Percent defoliation- lbs ai/ac Lower canopy Upper canopy RH-2485 (Intrepid) 0.15 20 < 5 80 WP Steward 1.25 SC 0.09 20 < 5 Steward 1.25 SC 0.065 25 < 5 RH-2485 (Intrepid) 0.01 30 < 5 80 WP Pirate 3 SC 0.2 35 4 Denim 0.16 0.01 40 10 Tracer 3 SC 0.045 40 15 Larvin 3.2 F 0.6 50 15 Untreated - 60 20 Lepinox 1.0 60 25 rr . rr. ~ r . rr . r 1999 COTTON RESEARCHREPORT 25 26 ALABAMA AGRICULTURAL EXPERIMENT STATION Intrepid at 0.1 and 0.15 pound active ingredient per acre gave the highest level of control of soybean loopers (Table 2). Other insecticides that significantly reduced looper numbers were Stew- ard, Pirate, Tracer, and Denim. Larvin gave some suppression, but not at the level of the newer insecti- cides. At four days posttreat- ...--4.M T ,.- .. . T"}. -,,1 . . .. TABLE 2. NUMBER OF LOOPERS PER Six Row FEET' Treatment Rate Loopers/6 row ft lbs ai/ac Count 1 Count 2 Count 3 Count 4 Avg. RH-2485 (Intrepid) 80 WP 0.15 5 6 7 10 7 RH-2485 (Intrepid) 80 WP 0.01 14 5 5 12 9 Steward 1.25 SC 0.09 14 16 4 12 11.5 Pirate 3 SC 0.2 19 25 2 15 15.25 Steward 1.25 SC 0.065 19 12 19 15 16.25 Tracer 3 SC 0.045 13 25 16 17 17.75 Denim 0.16 0.01 17 13 19 27 19.0 Larvin 3.2 F 0.6 29 32 25 21 26.75 Untreated - 31 30 35 42 34.5 Lepinox 1.0 40 49 31 45 41.25 loopers than the untreated Pretreatment count on August control. About 30 hours af- ter treatment, 1.5 inches of rain fell and this likely had an impact on all treatments. However, frequent thunderstorms are a normal occurrence in this part of Alabama and these results may be quite ost treatment. 27: 37.8 loopers per six row feet. typical of those that a grower might expect under on-farm condi- tions when rainfall occurs following treatment with these newer insecticides. ALABAMAAGRICULTURAL 'EXPERIMENT STATION 26 HERBICIDE APPLICATIONS ON-FARM COMPARISON OF COTTON WEED CONTROL IN ROUNDUP READY COTTON Charles Burmester The objective of this on-farm study was to compare two cotton weed control systems using a Roundup Ready cotton variety. One weed control system used a total postemergenceprogram ofRoundup Ultra while the other system used preemergenceapplicationsofCotoran (one pound) and Caparol (0.75 pound) in combination with postemergence application of Roundup Ultra. The test was located in Limestone County, Alabama. The cotton variety Deltapine DP 458BRR was planted on April 20. Plots were eight rows wide and ran the length of the field (1,600 feet). Plots were replicated three times across the field. Early season rainfall was excellent and produced rapid cot- ton and weed growth. The Roundup-only system had Roundup Ultra sprayed at the two and four leaf stage of cotton growth. Early season weed competition in this system was intense and cotton often could not be seen until the plots were sprayed. The preemergence application did an excellent job of early season weed control and Roundup Ultra was applied only at the four- leaf stage. Both systems controlled weeds, and cotton was essen- tially weed free as cotton approached the fifth and sixth leaf stage. In late season, pigweed became a problem in plots where no preemergence herbicides were used. Pigweeds between rows were controlled with Roundup Ultra using a hooded sprayer, but pig- weeds emerging in the row could not be controlled. EFFECT OF HERBICIDE SYSTEM ON ROUNDUP READY COTTON YIELDS Treatment Rate Growth stage Seed cotton yields ai/ac lbs/plot lbs/ac Cotoran IIb pre- 1103.3 a 1187 a Caparol 1.5 pt emergence Roundup Ultra 1 qt post- 1029.7 a 1105 a emerence LSD (0.10) 217.59 233.7 Means with the same letter are not significantly different at the p=0.10 level. Plots were harvested on September 13 and weighed in a boll buggy before being moduled. Yields (see table) were very low due to a late season drought, but yields were slightly higher in plots where a preemergence herbicide treatment was used. Under these conditions of intense early season weed pressure, use of low rates of preemergence herbicides with Roundup Ultra appears to be very beneficial. No herbicide damage to cotton was noted in any treatment. HARVEST AID EVALUATION FOR COTTON REGROWTH CONTROL Michael G. Patterson The objective of this research was to evaluate several cotton harvest aides for control of new growth in cotton that had been defoliated but had put out new leaves due to a delay in harvesting. A field of cotton was defoliated using Def 6 at one pint per acre approximately three weeks before treatment with several harvest aides on October 13. Treatments were applied in 10 gallons of solution per acre using 8002 flat fan nozzles spaced 20 inches apart on the boom. Cotton was approximately 40 inches tall at application and air tem- perature was 780 F with 80% relative humidity. Plots were planted with Paymaster PM 1220BG/RR on May 22 at the Monroeville Research Field. Plots consisted of four rows, 30 feet long with 38-inch row spacing and were arranged in a randomized complete block design with four replications. Visual estimates of leaf removal were made at five and 12 days after treatment on a scale of 0 to 100 where 0 = no leaves removed and 100 = all leaves removed. GREEN LEAF REMOVAL FROM COTTON BY VARIOUS COTTON HARVEST AIDES Treatment Rate 5 DAT 12 DAT ai/ac % % Untreated - 0 0 Def 6 1.5 pt 87 89 Def 6 0.5 pt 50 71 Dropp 50 W 0.1 Ib Harvade 5F 6 oz 52 76 Ginstar 1.5E 2 oz Crop oil concentrate 1 pt Prep 6 12 oz 55 64 Def 6 6 oz Crop oil concentrate 1 pt continued r~ill Iv ~CiC~il.4illll I iillll jltl WilS CXII-:IIt:IIl ilrlIl rlII11111~:~(I I~irl~ll(l IIII, 1999 COTTON RESEARCHREPORT 27 28 ALABAMA AGRICULTURAL EXPERIMENT STATION Visual estimates of green leaf removal varied from 87 % (Def at 1.5 pints) to 0 % (untreated) at five days after treat- ment (see table). Sodium chlorate at three quarts alone pro- vided 66% removal followed by CottonQuik at two pints, Ginstar at two ounces plus Finish at one pint, and Quickpick at one pint plus sodium chlorate at two quarts, each providing 60% leaf removal. At 12 days after treatment, Def provided 89% removal, followed by Ginstar at four fluid ounces, Ginstar plus Finish, and Harvade plus Ginstar plus crop oil concen- trate. Lower than labeled rates of several newer products such as Ginstar (minimum six fluid ounces per acre) and Finish (minimum rate two pints) were used to evaluate their potential as low cost alternatives. If cotton will be harvested less than one week after applica- tion, then Def or Folex (phosphoro-trithioate) would be a good choice. Based on this one trial, if cotton will not be harvested within two weeks, then Def or Folex or Ginstar alone or in mix- ture with Finish or Harvade would work well. Harvest aid activ- ity is dependent on several factors such as the spray coverage GREEN LEAF REMOVAL FROM COTTON BY VARIOUS COTTON HARVEST AIDES, CONTINUED Treatment Rate 5 DAT 12 DAT ai/ac % % CottonQuik 2 pts 60 70 Finish 4 1 pt 34 41 Quickpick 3.1 1 pt 16 25 Na Chlorate 6 3 qts 66 69 Ginstar 1.5E 2 oz 60 76 Finish 4 1 pt Quickpick 3.1 1 pt 60 66 Na Chlorate 6 2 qts Starfire 2 oz 59 72 surfactant 0.25% Prep 6 1.33 pt 36 4 obtained and the temperature and humidity at time of application and for several days afterward. VALOR 50 WDG FOR LAYBY WEED Michael G. Patterson The objective of this research was to evaluate Valor herbi- cide as a potential replacement for cyanazine (Bladex) in cotton production for use in layby applications. Valor was used alone or in tank mix with MSMA and evaluated for late-season control of emerged weeds. Crop injury was also evaluated. Plots were planted May 25 with Deltapine DP 5415 cotton at the E. V. Smith Research Center, Tallassee, Alabama. Plots were four rows wide and 30 feet long, with a 36-inch row spac- ing. Applications were made using a 15003 flat fan nozzle run- ning between cotton rows and calibrated to deliver 15 gallons of solution per acre. Weed species and size at application were as follows: annual grass (50% goosegrass, 50% large crabgrass), eight CONTROL IN COTTON inches; pigweed (50% hybrid, 50% spiney), 10 inches; yellow nutsedge, eight inches; entireleaf morningglory, 18 inches; and sicklepod, nine inches. Visual weed control and crop injury rat- ings were made 14 days after treating where 0 = no control or injury and 100 = complete control or death. Valor at 0.063 pound active ingredient per acre with crop oil concentrate (COC) directed to the base of 14-inch tall cotton controlled annual grasses (46%), pigweed (91%), yellow nutsedge (39%), morningglory (93%), and sicklepod (89%) at 14 days af- ter treatment (see table). Crop injury was minimal. Valor at 0.063 pound active ingredient per acre plus MSMA at two pounds with COC controlled annual grasses (71%), pigweed (93%), yellow nut- EFFECTS OF VALOR 50 WDG HERBICIDE ON COTTON AND SELECTED WEEDS Treatment Rate CI GRS PW NSZ MG SP lbs ai/ac (%) Untreated - 0 0 0 0 0 0 Valor 0.063 3 46 91 39 93 89 COC2 2 pts Valor 0.063 6 71 93 70 94 94 MSMA 2.0 COC 2 pts CY-PRO 0.75 5 80 75 65 94 89 MSMA 2.0 COC 2 pts SCI= crop injury, GRS= grass, PW= pigweed, NSZ= nutsedge, MG= morningglory, SP= sicklepod. 2 COC = crop oil concentrate. sedge (70%), momingglory (94%), and sicklepod (94%). For comparison,CY-PRO (cyanazine) at 0.75 pound ac- tive ingredient per acre plus MSMA at two pounds with COC controlled annual grasses (80%),pigweed(75%),yellow nutsedge (65%), momingglory (94%), and sicklepod (89%). In conclusion, Valor plus MSMA provided weed control equal to or better than cyanazine plus MSMA and would provide an acceptable alternative to this standard layby treatment. / .\ . . . 28 ALAE3AMAAGRICULTURALExPERIMENT STATION NEMATICIDE APPLICATIONS IMPACT OF VARIOUS CROP ROTATIONS AND WINTER COVER CROPS ON RENIFORM NEMATODE IN COTTON William S. Gazaway, James R. Akridge, and Kathy McLean The purpose ofthis test was to reaffirm the ability ofnonhost crops to reduce reniform nematode populations and to determine if certain winter cover crops or fallow will reduce reniform nema- tode populations to safe levels. A field near Huxford, Alabama, was selected for the test. This sandy loam field has had a high infestation of Reniform nema- tode for more than 12 years and, as a result, has suffered substan- tial cotton yield losses during that period. Corn (DeKalb 683), soybean (Centennial), peanut (Southern Runner), cotton (Deltapine DP 458BRR), and cotton treated with a nematicide (Temik 15G?) were planted on May 25, 1998 in assigned plots. Cotton, which did not receive Temik 15G (aldicarb), was treated with the insec- ticide Di-Syston 15G? at seven pounds per acre for early season insect control. Vetch (Cahaba White), rye (Wren's Abruzzi), and fallow followed the summer crop harvest in the fall of 1998. The experimental design was a split plot, randomized de- sign with five replications. Main plots were the winter cover crops and fallow. On May 11, the cotton variety Deltapine DP 655BRR or cotton treated with Temik 15G at seven pounds per acre was planted in all plots. Plots consisted of four 36-inch rows 25 feet long. Soil samples were pulled for nematode analyses from the two inner rows of each plot on May 22, 1998; July 7, 1998; Au- gust 19, 1998;November 10, 1998; May 11, 1999; July 22, 1999; and October 7, 1999. Cotton was harvested from the two inner rows of each plot on October 21, 1999. All other cultural prac- tices, weed control, and insect control were implemented accord- ing to Auburn University recommendations. TABLE 1. EFFECT OF 1998/1999 WINTER COVER CROPS AND FALLOW ON 1999 COTTON PRODUCTION Winter cover crop Seed cotton yield lbs/ac Vetch 2849 a Fallow 2615 b Rye 2085 c LSD (0.05) 233 Means with the same letter are not significantly different at the p=0.05 level. Cotton production varied significantly following rye, vetch, and winter fallow (Table 1). Cotton following vetch had higher yields than cotton following fallow or rye. The better-than-ex- pected cotton yields in the plots following vetch could be attrib- uted to the additional nitrogen produced by this legume. Plots with winter rye produced the lowest cotton yields in 1999. Considering that rye is not a host to Reniform nematode, these results were surprising. The low cotton yield following rye is believed to be attributed to a nitrogen deficiency, induced by a "green manure" effect. The rye was fairly large when turned un- der in the late spring. Cotton planted in the rye plots showed signs of nitrogen deficiency throughout the 1999 season. The winter cover crops or fallow did not appear to impact Reniform nema- tode reproduction since there were no significant differences in nematode populations in the spring of 1999. Rotation with nonhost crops in 1998 significantly affected both Reniform nematode populations and subsequent cotton yields in 1999. The 1998 peanut and corn crops were the most effective in reducing nematode populations in the spring of 1999. Reni- form populations were surprisingly high in plots following the 1998 soybean crop and high, as expected, in plots following cot- ton and cotton treated with a nematicide (Figure 1). By the end of the 1999 cotton season in October, Reniform nematode popula- tions had rebounded to lethal levels in all treatments. Whilenonhost crops, including corn, peanut, and soybean, failed to keep Reni- form populations at low levels throughout the growing season, these crops did significantly outproduce the continuous cotton TABLE 2. IMPACT OF CROP ROTATION WITH NONHOST 1998 SUMMER CROPS ON COTTON PRODUCTION IN 1999 1998 crop Seed cotton yield lbs/ac Corn 2808 a Peanut 2739 a Soybean 2720 a Cotton 2175 b Cotton + Temik 2139 b LSD (0.05) 21 Means with the same letter are not significantly different at the p=0.05 level. 1999 COTTON RESEARCHREPORT 29 30 ALABAMA AGRICULTURAL EXPERIMENT STATION nematicide-treated and untreated plots (Table 2). In this particu- lar field, Temik 15 G (aldicarb) at seven pounds per acre failed to increase cotton yields in 1998 and in 1999 (Table 3). TABLE 3. COTTON PRODUCTION RESPONSE TO TEMIK 15G IN CONTINUOUS COTTON Seed cotton yield Average Treatment 1998 1999 yield lbs/ac lb/sac lbs/ac Temik 15G 1995 a 2139 a 2067 DiSyston 15G 1786 a 2175 a 1981 LSD (0.05) 360 218 Means with the same letter are not significantly different at the p=0.05 level. I Alternating nonhost crops such as corn, peanut, and certain soybean cultivars (i.e., Centennial) every other year with cotton appears to increase cotton production in Reniform nematode-in- fested fields. Temik's failure to improve cotton yields in this heavily infested Reniform nematode field for two consecutive years is surprising since this nematicide has performed effectively in other similar cotton fields. Its failure to get positive yield re- sponse could be due to the following: (1) The environmental con- ditions at the time of application could be unfavorable. (2) Temik could be inable to effectively control high reniform populations. (3) Reniform populations could be developing resistance to Temik. (4) Soil microbes in this field could be breaking down Temik (aldicarb) into compounds harmless to the nematode. More studies must be conducted to determine which might be the cause. Effect of summer on reniform nematode populations in 1998. 600W Miy-98 JIn-98 Jul-98 Aug-98 Sep98 Oct-98 Nov-98 ALABAMAAGRICULTURALEXPERIMENT STATION 30 EFFECT OF FALL AND SPRING TELONE FUMIGATION ON THE MANAGEMENT OF RENIFORM NEMATODES IN COTTON William S. Gazaway, James R. Akridge, and Kathy McLean Telone II, 1,3-dichloropene, is an effective fumigant for man- aging Reniform nematodes (Rotylenchulus reniformis) in cotton when applied under the proper soil conditions. During fall and spring, cotton producers are more likely to encounter cold, wet soils that would impede the movement of the fumigant and lead to possible damage to cotton seedlings. For this reason, it is be- lieved that soil conditions in the fall would be more favorable for fumigation than in the spring. The purpose of this test was to determine if fall fumigation is superior to spring fumigation in managing reniform nematodes in cotton. A cotton field heavily infested with Reniform nematodes was selected for the test. The field (loam soil) was cultivated and bedded. Treatments were arranged in a randomized complete block design and replicated five times. In the fall, Telone II was in- jected 14 to 16 inches deep into raised seed beds at rates of three gallons per acre and five gallons per acre, respectively. All other plots that did not receive a fumigant were ripped with a shank as well. After fumigation, rye was planted over the test area. In the spring, Telone was applied to designated plots. Again, all plots were ripped with a shank. Cotton was planted to all plots one week following fumigation. All plots except for the Temik-treated plots were treated with Di-Syston in the seed furrow at planting for early insect control. All other fannrming practices were followed according to Auburn University recommendations. Soil samples for nematode analyses were taken before fall fumigation on November 1, 1998; during the winter on February 10, 1999; before spring fumigation on May 11; in the middle of the growing season on July 22; and at harvest on October 21. TABLE 1. IMPACT OF FUMIGATION ON COTTON PRODUCTION Nematicide Rate Time of Seed cotton per acre application yield lbs/ac Telone II 5 gals Fall 2313 a Telone II 3 gals Fall 2312 a Telone II 3 gals Spring 2193 a Temik 15G 7 Ibs Spring 2095 ab Di-Syston 15G 7 Ibs Spring 1961b LSD (0.05) 205 Means with the same letter are not significantly different at the p=0.05 level. During both spring and fall, Telone-fumigated plots pro- duced slightly better yields than Temik-treated plots and signifi- cantly better yields than the plots not receiving a nematicide (Table 1). Fall fumigation was slightly superior to spring fumigation in this test. However, there were no differences between the three gallons and the five gallons per acre fall application rates of Telone. The slight difference between fall and spring Telone appli- cation could be due to the relatively favorable conditions for Telone application in the spring of 1999. More tests need to be conducted over time and under more adverse conditions in the spring to de- termine if fall application of Telone would indeed be superior. Fall application of Telone did appear to reduce reniform nema- tode populations significantly in the spring (Table 2). Popula- tions in all treatments rebounded to damaging levels by the end of the growing season, however. TABLE 2. EFFECT OF FUMIGATION ON RENIFORM NEMATODE POPULATIONS Nematicide Rate per acre Timing - Reniform nematodes per 100 cc soil- 11/1/98 2/10/99 5/11/99 7/22/99 10/21/99 Telone II 5 gals Fall 1084 a 1036 c 230 c 2177 a 1505 a Telone II 3 gals Fall 1486 a 957 c 392 bc 1995 a 1603 a Telone II 3 gals Spring 1396 a 1507 bc 1000 a 2396 a 1052 a Temik 15G 7 Ibs Spring 1456 a 2015 ab 647 b 2310 a 1173 a Di-Syston 7 Ibs Spring 1678 a 2533 a 621 b 2453 a 1476 a LSD (0.05) 802 882 336 1249 763 1999 COTTON RESEARCHREPORT 31 FUNGICIDE APPLICATIONS EVALUATION OF SELECTED EXPERIMENTAL SEED TREATMENTS FOR CONTROL OF SEEDLING DISEASE OF COTTON Kathy S. McLean and William S. Gazaway The objective of this test was to evaluate selected esperimental cotton seed treatments for control of Rhizoctonia solani and Pythium spp. for seedling disease of cotton. LS 288 and RTU BaytanThiram + Allegiance were applied to a known amount of seed in a ziploc bag and shaken until completely cov- ered and then allowed to dry before planting. All other fungicides were applied to the seed by the manufacturer. Each plot was in- fested with Pythium spp. and R. solani by applying inocu- lated millet seed in the fur- TABLE 1. EFFECT OF SELE row at planting. AND PL, Plots were planted at the Treatment Tennessee Valley Research and Extension Center with Stoneville 474 on May 3. Untreated control Plots consisted of two rows, Vitavax-PCNB + Allegiance FL 25 feet long and 40 inches RTU Baytan Thiram + Apron FL wide. Blocks were separated NU-Flow T + Nu-Flow M + Apron by 20-foot alleys and were Maxim + Nu-Flow M + Apron XL WE-120C + Nu-Flow M + WE-14 arranged in a randomized Nu- Fiow M + WE-i4 complete block design with WE-142 + WE-147 + four replications. All plots Nu-Grow Film Coat were maintained throughout LS 288 the season with standard her- RTU Baytan Thiram + Allegianc bicide, insecticide, and fertil- LSD (0.05) ity production practices as Means with the same letter are recommended by the Ala- bama Cooperative Extension System. TABLE 2. EFFECT OF SELE Stand counts were col- AND PL lected on May 19 and June ' 2. Plant maturity was esti- Treatment mated by the percent of open bolls on September 10. Plots Untreated control were harvested on September Vitavax-PCNB + Allegiance FL 28. Data were subjected to RTU Baytan Thiram + Apron FL ANOVA appropriate for the NU-FlowT + Nu-Flow M + Apron experimental design used and Maxim + Nu-Flow M + Apron Xl means were separated using WE-120C + Nu-Flow M + WE-14 the least significant differ- Nu-Grow Film Coat WE-142 + WE-147 + ence test. All statistical tests Nu-Grow Film Coat were performed at the 5% LS 288 level of significance. RTU Baytan Thiram + Allegianc Significant differences LSD (0.05) in seedling stand were ob- Means with the same letter ar served at 16 and 30 days after planting. At two and four weeks after planting, Vitavax-PCNB + Allegiance FL, WE -120C +Nu- Flow M + WE-147 + Nu-Grow Film Coat, and RTU Baytan Thiram + Allegiance had significantly greater stands than the un- treated control (Tables 1 and 2). Vitavax-PCNB + Allegiance FL and RTU Baytan Thiram + Allegiance also produced a signifi- cantly lower skip index indicating a more uniform seedling stand "CTED SEED TREATMENTS ON COTTON STAND, SKIP INDEX, ANT VIGOR 16 DAYS AFTER PLANTING Rate Emergence Plants Skip Vigor fl oz/cwt per 10 ft per foot index rating of row of row - 14.25 d 0.57 d 20.0 a 3.0 a 6.0 + 0.75 46.25 a 1.85 a 10.5 c 3.62 a 3.0 + 0.75 23.75 bcd 0.95 bcd 16.2 abc 3.25 a XL 2.25 + 1.25 + 0.32 25.25 bcd 1.01 bcd 15.0 abc 2.88 a . 0.08 + 1.75 + 0.32 26.0 bcd 1.04 bcd 16.8 ab 3.38 a 7 + 0.24 + 1.25 + 2.0 37.25 ab 1.49 ab 14.3 abc 3.50 a + 2.0 2.0 + 2.0 17.5 cd 0.70 cd 15.8 abc 3.00 a + 2.0 0.5 oz/cwt 24.0 bcd 0.96 bcd 16.0 abc 3.50 a e 3.0 + 0.75 oz/cwt 33.0 abc 1.32 abc 13.8 bc 3.38 a 17.30 0.69 5.9 0.96 not significantly different at p=0.05. ECTED SEED TREATMENTS ON COTTON STAND, SKIP INDEX, ANT VIGOR 30 DAYS AFTER PLANTING Rate Emergence Plants Skip Vigor fl oz/cwt per 10 ft per foot index rating of row of row - 9.75 c 0.39 c 21.3 a 2.25 b 6.0 + 0.75 31.00 a 1.24 a 14.8 b 3.75 a 3.0 + 0.75 18.75 abc 0.75 abc 18.3 ab 2.88 ab XL 2.25 + 1.25 + 0.32 22.25 abc 0.89 abc 18.8 ab 3.38 ab L 0.08 + 1.75 + 0.32 19.25 abc 0.77 abc 20.0 ab 3.25 ab 7 + 0.24 + 1.25 + 2.0 28.00 ab 1.12 ab 15.2 ab 3.38 ab + 2.0 2.0 + 2.0 15.00 bc 0.60 bc 19.0 ab 2.63 ab + 2.0 0.5 oz/cwt 20.25 abc 0.81 abc 17.5 ab 3.38 ab e 3.0 + 0.75 oz/cwt 25.25 ab 1.01 ab 18.0 ab 2.75 ab 14.34 0.57 6.0 1.14 e not significantly different at p=0.05. 32 ALABAMAAGRICULTURALEXPERIMENT STATION 1999 CoTTON RESEARCH REPORT 33 than the untreated control. However, 30 days after planting only Vitavax-PCNB + Allegiance FL produced a significantly lower skip index. TABLE 3. EFFECT OF SELECTED SEED TREATMENTS ON P SEED COTTON YIELD Treatment Rate Op fl oz/cwt Untreated control Vitavax-PCNB + Allegiance FL 6.0 + 0.75 RTU Baytan-Thriam + Apron FL 3.0 + 0.75 NU-Flow T + Nu-FLow M + Apron XL 2.25 + 1.25 + 0.32 Maxim + Nu-Flow M + Apron XL 0.08 + 1.75 + 0.32 WE-120C + Nu-Flow M + WE-147 + 0.24 + 1.25 + 2.0 Nu-Grow Film Coat + 2.0 WE1142 + WE-147 + Nu-Grow Film Coat 2.0 + 2.0 + 2.0 LS 288 0.5 RTU Baytan Thiram + Allegiance 3.0 + 0.75 oz/cwt LSD Means with the same letter are not significantly different at p=0.05. No significant differences were observed in the number of open bolls on five plants per plot (Table 3). Seed cotton yields ranged from 2,540 pounds per acre to 1,094 pounds per acre for the Vitavax-PCNB + Alle- giance FL and the untreated SERCENT OPEN BOLLS AND control, respectively. Vitavax-PCNB + Allegiance en bolls Seed cotton yield FL, Maxim + Nu-Flow M + % lbsac Apron XL, WE -120C + Nu- Flow M + WE-147 + Nu- 45 a 1094 d Grow Film Coat and RTU 52 a 1656 bcd Baytan Thiram + Allegiance 40 a 1721 bcd all produced significantly 48 a 1956 abc greater yields than the con- 55 a 2325 ab trol. Averaging all fungicide treatment yields together pro- 42 a 1450cd duced an increase of 606 40 a 1440 cd pounds of seed cotton per 19 729 acre greater than the un- treated control. EVALUATION OF SELECTED SEED TREATMENTS FOR CONTROL OF SEEDLING DISEASE OF COTTON Kathy S. McLean and William S. Gazaway The objective of this test was to evaluate selected cotton seed treatments for control seedling disease of cotton. All seed treatments were applied by the manufacturer prior to planting. Each plot was infested with Pythium spp. and Rhizoctonia solani by applying inoculated millet seed in the furrow at planting. Plots were planted at the Tennessee Valley Research and Extension Center with Stoneville 474 on May 3. Plots consisted of two rows, 25 feet long and 40 inches wide. Blocks were sepa- TABLE 1. EFFECT OF SELECTED SEED TREATMENTS ON C AND PLANT VIGOR 16 AND 30 DAYS AFTEF Treatment Rate Emergence/ fl oz/cwt 10 ft of row 16 DAP Untreated control (black seed) - 7.3 c Vitavax-PCNB + Allegiance FL 6.0 + 0.75 28.0 a RTU Baytan Thiram + Apron FL 3.0 + 0.75 14.0 bc NU-FlowT + Nu-Flow M + Apron XL 2.25 + 1.25 + 0.32 21.5 ab Nu-FlowT + Nu-Flow M + WE-147 2.25 + 1.25 + 2.0 26.0 ab WE-146 + WE-144 + Nu-FlowT+ 0.0353 + 0.0353 25.5 ab Nu-Flow M + WE-147+ + 2.25 + 1.25 Nu-Grow Film Coat + 2.0+ 2.0 WE-146 + WE-144 + 0.0353 +0.0353 29.5 a Nu-Grow Film Coat + 2.0 LSD (0.05) 13.2 Means with the same letter are not significantly different at p=0.0 rated by 20-foot alleys and the test was arranged in a randomized complete block design with four replications. All plots were main- tained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Ala- bama Cooperative Extension System. Stand counts were collected on May 19 and June 2. Plant maturity was estimated by the percent of open bolls on Septem- ber 10. Plots were harvested on September 28. Data were sub- jected to statistical analysis appropriate for the experi- OTTON STAND, SKIP INDEX, mental design used and R PLANTING means were separated using Emergence Skip Vigor the least significant differ- 10 ft of row index rating ence test. All statistical tests 30 DAP were performed at the 5% 14.0 c 36.3 a 2.3 a level of significance. 42.8 a 20.8 c 1.4 b Significant differences 23.0bc 29.5 ab 1.8 abc in seedling stand were ob- 35.3 ab 24.8 bc 1.6 bc served among treatments. At 33.8 ab 22.0 bc 1.5 bc 16and30daysafterplanting, 37.5 ab 22.3 bc 3.5 a Vitavax-PCNB + Nu-Flow M,Nu-Flow T+Nu-Flow M 40.8 a 23.3 bc 3.00 a +Apron XL ,Nu-Flow T + Nu-Flow M + WE 147, WE 16.1 7.8 0.96 146 +WE 144 +Nu-Flow T 5. + Nu-Flow M + WE 147 + 1999 COTTON RESEARCHREPORT 33 34 ALABAMA AGRICULTURAL EXPERIMENT STATION Nu-Gro Film Coat, and WE 146 + WE 144 + Nu-Grow Film Coat produced signifi- cantly greater stands than the untreated control (Table 1). The highest skip index was in the control. Vitavax-PCNB + Nu-Flow M had the lowest skip index indicating this treatment produced a more evenly spaced seedling stand than the control. Three of the fungicide seed treatments produced an increased percentage of open bolls thus indicating earlier maturity (Table 2). Seed cot- ton yields ranged from 2,135.5 per acre for the Vitavax-PCNB TABLE 2. EFFECT OF SELECTED SEED TREATMENTS ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield fl oz/cwt % lbs/ac Untreated control (black seed) - 32.2 b 858.8 b Vitavax-PCNB + Nu-flow M 6.0 + 0.75 46.5 ab 2135.5 a RTU Baytan-Thiram + Apron FL 3.0 + 0.75 47.9 a 1756.8 a NU-FlowT + Nu-Flow M + Apron XL 2.25 + 1.25 + 0.32 47.4 ab 1809.1 a Nu-Flow T + Nu-Flow M + WE 147 2.25 + 1.25 + 2.0 52.7 a 1799.2 a WE-146 + WE-144 + Nu-Flow T + 0.0353 + 0.0353 + 2.25 54.4 a 2027.8 a Nu-Flow M + WE-147+ + 1.25+ +2.0 Nu-Grow Film Coat + 2.0 WE-146 + WE-144 + 0.0353 +0.0353 42.1 ab 2083.3 a Nu-Grow Film Coat + 2.0 LSD (0.05) 15.3 546.8 Means with the same letter are pounds per acre to 858.8 pounds + Nu-Flow M and the untreated not significantly different at p=0.05. control, respectively. All seed treatments significantly increased the seed cotton yield compared to the control. EVALUATION OF IN-FURROW FUNGICIDE TREATMENTS AND FUNGICIDE BIOLOGICALS FOR CONTROL OF SEEDLING DISEASE OF COTTON K. S. McLean and W. S. Gazaway The objective of this project was to evaluate selected in- furrow fungicides for control of Rhizoctonia solani and Pythium spp. on seedling disease of cotton. All fungicides were applied as an in-furrow granular or spray application at planting. Two seed treatments, LS 288 and RTU Baytan Thiram + Allegiance were applied to a known amount of seed in a ziploc bag and shaken until the seed was covered and then allowed to dry be- fore planting. Each plot was TABLE 1. EFFECT OF SELECTE infested with Pythium spp. BY CoTToN STAND, SKIF and R. solaniby applying in- oculated millet seed in the furrow at planting. Plots were planted at the Wiregrass Research and Extension Center with Deltapine NuCotn 35B on April 20. Plots consisted of two rows, 25 feet long and 40 inches wide. Blocks were separated by 20-foot alleys and were arranged in a ran- domized complete block de- sign 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 Sys- tem. Stand counts were collected on May 5 and May 18. Plant maturity was estimated by the percent of open bolls on Septem- ber 16. Plots were harvested on September 29. Data were sub- D IN-FURROW FUNGICIDES ON SEEDLING DISEASE AS MEASURED P INDEX, AND PLANT VIGOR AT 15 DAYS AFTER PLANTING Treatment Rate Emergence Plants Skip Vigor per 25 ft per foot index rating of row of row Untreated control - 22.0 e 0.88 d 30.6 a 2.0 c Terraclor 2E 48 fi oz/ac 55.8 d 2.23 c 16.6 cd 2.7 ab Terraclor 15G 5.5 Ibs/ac 74.4 bcd 2.98 abc 10.2 de 2.8 ab Rovral 4F 5.2 fl oz/ac 96.2 a 3.71 a 8.6 e 2.9 ab TSX 18.8G 5.5 lbs/ac 28.4 e 1.14 d 29.4 ab 2.0 c TSX EC 64 oz/ac 93.4 ab 3.74 a 8.6 e 3.0 a Ridomil Gold PC 11G 7.0 Ibs/ac 85.6 abc 3.42 ab 10.2 de 2.8 ab TSX 18.8G 7.0 Ibs/ac 88.2 abc 3.53 ab 6.6 e 2.9 ab TSX G/WGB49 7.4 Ibs/ac 86.2 abc 3.45 ab 11.0 de 2.7 ab TSX G/WGB49 5.5 lbs/ac 71.2 cd 3.85 bc 12.6 de 2.9 ab RTU Baytan Thiram + Allegiance 3.0 + 0.75 oz /cwt 26.2 e 1.05 d 31.8 a 2.5 b LSD (0.05) 20.58 0.82 7.28 0.47 Means with the same letter are not significantly different at p=0.05. ni Aa~r r r v . ~ he~ 34 ALABAMAAGRICULTURALEXPERIMENT STATION I 1999 CorroN RESEARCH REPORT 35 jected to statistical analysis appropriate for the experimental de- sign used and means were separated using the least significant difference test. All statistical tests were performed at the 5% level of significance. Significant differences in seedling stand were observed at 15 and 28 days after planting. In the R. solani inoculated rows, Terraclor 2E, Terraclor 15G, Rovral 4F, TSX EC, Ridomil Gold PC 1 IG, TSX 18,8 (seven pounds per acre) and TSX G/WGB49 (5.5 pounds per acre and 7.4 TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON SEEDLING DISEASE AS MEASURED BY COTTON STAND AND SKIP INDEX AT 28 DAYS AFTER PLANTING Treatment Rate Emergence Plants Skip per 25 ft per foot index of row of row Untreated control - 15.0 d 0.60 d 31.4 a Terraclor 2E 48 fl oz/ac 39.4 c 1.58 c 16.2 b Terraclor 15G 5.5 Ibs/ac 65.4 ab 2.62 ab 8.2 cd Rovral 4F 5.2 fl oz/ac 84.0 a 3.36 a 9.0 bcd TSX 18.8G 5.5 lbs/ac 15.8 d 0.63 d 30.2 a SX EC 64 oz/ac 74.8 ab 2.99 ab 7.8 cd Ridomil Gold PC 11G 7.0 lbs/ac 72.8 ab 2.91 ab 12.2 bcd TSX 18.8G 7.0 Ibs/ac 77.4 a 3.09 a 6.6 d TSX G/WGB49 7.4 Ibs/ac 77.0 a 3.08 a 7.8 cd TSX G/WGB49 5.5 Ibs/ac 58.2 b 2.33 b 14.2 bc RTU Baytan Thiram + Allegiance 3.0 + 0.75 oz /cwt 18.8 d 0.75 d 32.2 a LSD (0.05) 18.75 0.75 7.33 Means with the same letter are not significantly different at p=0.05. TABLE 3. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control - 49.44 2091 ab Terraclor 2E 48 fl oz/ac 59.82 1951 b Terraclor 15G 5.5 Ibs/ac 48.49 2300 ab Rovral 4F 5.2 fl oz/ac 59.60 2277 ab TSX 18.8G 5.5 lbs/ac 55.41 2056 ab TSX EC 64 oz/ac 62.66 2114 ab Ridomil Gold PC 11 G 7.0 Ibs/ac 58.78 2335 ab TSX 18.8G 7.0 Ibs/ac 54.08 2323 ab TSX G/WGB49 7.4 Ibs/ac 53.61 2474 a TSX G/WGB49 5.5 Ibs/ac 56.72 2300 ab RTU Baytan Thiram + Allegiance 3.0 + 0.75 oz/cwt 55.29 2207 ab LSD (0.05) 11.15 431.96 Means with the same letter are not significantly different at p=0.05. pounds per acre) produced greater stands and lower skip indices than the control at 15 and 28 days after planting (Tables 1 and 2). In the Pythium spp. inoculated rows, Terraclor 15G, Rovral 4F, TSX EC, TSX 18,8 (seven pounds per acre) and TSX G/WGB49 (5.5 pounds per acre and 7.4 pounds per acre) produced greater stand and lower skip indices than the control at 15 days after planting. However, by 28 days after planting, only TSX EC and TSX G/WGB (7.4 pounds per acre) produced greater stands and lower skip indices than the control. The inoculated rows were combined for yields. TSX EC produced a signifi- cantly higher percentage of open bolls than the control, indicating earlier maturity (Table 3). Seed cotton yields ranged from 2,474 pounds per acre to 1,951 pounds per acre for the TSX G/WGB (7.4 pounds per acre) and Terraclor 2EC treatments, respectively (Table 3). The average fungicide yield com- pared to the control increased the seed cotton 182 pounds per acre. 1999 COTTON RESEARCHREPORT 35 EVALUATION OF SELECTED IN-FURROW FUNGICIDES AND FUNGICIDE BIOLOGICAL COMBINATIONS FOR CONTROL OF SEEDUNG DisEAsE OF CCTION Kathy S. McLean and William S. Gazaway The objective of this project was to evaluate selected in- furrow fungicides and fungicide biological combinations for con- trol of Rhizoctonia solani and Pythium spp. on seedling disease of cotton. All fungicides were applied as an in-furrow granular or spray application at planting. Each plot was infested with Pythium spp. and R. solani by applying inoculated millet seed in the fur- row at planting. Plots were planted at the Tennessee Valley Research and Extension Center with Deltapine NuCotn 35B on April 20. Plots consisted of two rows, 25 feet long and 40 inches wide. Plots 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. Stand counts were collected on May 12 and May 25. Plant maturity was estimated by the percent of open bolls on Septem- ber 10. Plots were harvested on September 28. Data were sub- jected to statistical analysis appropriate for the experimental de- sign used and means were separated using the least significant difference test. All statistical tests were performed at the 5% level of significance. At 22 and 35 days after planting all fungicide treatments had significantly greater stands than the control (Table 1). At 22 days after planting, Terraclor Super X G/WGB49 at 7.4 pounds per acre produced the greatest stand at 3.6 plant per foot of row and the control produced the lowest with 0.4 plant per foot of row. All fungicides produced significantly lower skip indexes than the control. No differences in maturity were observed as measured by the percent open bolls (Table 2). Seed cotton yields ranged from 3,350.3 pounds per acre to 2,122.5 pounds per acre for the Terraclor Super X G/WGB49 at 7.4 pounds per acre and the con- trol treatments, respectively (Table 2). All fungicide treatments produced significantly greater yields than the control. TABLE 1. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON COTTON STAND, SKIP INDEX, AND PLANT VIGOR AT 22 AND 35 DAYS AFTER PLANTING Treatment Rate Emergence/ Emergence/ Skip Vigor 10 ft of row 25 ft of row index rating 22 DAP 35 DAP 22 DAP 35 DAP Untreated control -4.0d 11.8 d 33.0 a 3.1 a Terraclor Super X 18.8 G 7.0 lbs/ac 28.3 ab 63.3 ab 7.3 c 1.9 b Terraclor Super X 18.8 G 5.5 Ibs/ac 27.5 ab 67.5 ab 4.8 c 1.7 b Terraclor Super X G/ WGB 49 5.5 Ibs/ac 35.0 ab 66.3 ab 3.5 c 1.6 b Terraclor Super X G/WGB 49 7.4 lbs/ac 36.0 a 75.3 a 2.8 c 1.8 b Terraclor Super X EC 64 oz/ac 26.3 ab 61.8 b 4.8 c 1.6 b Ridomil Gold PC 11 G 7.0 lbs/ac 25.8 b 61.5 b 5.3 c 2.1 b Rovral 5.3 oz/ac 15.8 c 30.8 c 19.3 b 2.1 b LSD (0.05) 9.1 11.8 4.2 0.7 Means with the same letter are not significantly different at p=0.05. TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control 46.9 a 2122.5 b Terraclor Super X 18.8 G 7.0 lbs/ac 51.1 a 3281.7 a Terraclor Super X 18.8 G 5.5 Ibs/ac 53.2 a 3089.0 a Terraclor Super X G/ WGB 49 5.5 Ibs/ac 57.5 a 3131.5 a Terraclor Super X G/WGB 49 7.4 Ibs/ac 53.5 a 3350.3 a Terraclor Super X EC 64 oz/ac 55.9 a 3193.5 a Ridomil Gold PC 11G 7.0 Ibs/ac 56.8 a 3242.5 a Rovral 5.3 oz/ac 51.8 a 3000.9 a LSD (0.05) 16.9 395.4 Means with the same letter are not significantly different at p=0.05. 36 ALABAMAAGRICULTURALEXPERIMENT STATION 1999 CorroN RESEARCH REPORT 37 EVALUATION OF TERRACLOR AND ROVRAL FOR CONTROL OF SEEDLING DISEASE OF COTTON IN CENTRAL ALABAMA Kathy S. McLean and William S. Gazaway The objective of this research was to evaluate selected in- furrow granular and spray fungicides for control of Rhizoctonia solani and Pythium spp. on seedling disease of cotton. All fungi- cides were applied as an in-furrow granular or spray application at planting. Each plot was infested with Pythium spp. and R solani by applying inoculated millet seed in the furrow at planting. Plots were planted at the Prattville Research Field with Deltapine DP 436RRon April 14. Plots consisted of two rows, 25 feet long and 40 inches wide. Plots were arranged in a random- ized complete block design with four replications. All plots were maintained throughout the season with standard herbicide, insec- ticide, and fertility production practices as recommended by the Alabama Cooperative Extension System Stand counts were collected on May 4 and May 18. Plant maturity was estimated by the percent of open bolls on Septem- ber 9. Plots were harvested on September 28. Data were sub- jected to statistical analysis appropriate for the experimental de- sign used and means were separated using the least significant difference test. All statistical tests were performed at the 5% level of significance. Significant differences in seedling stand were observed. At 20 days after planting, Terraclor 15G and Rovral 4F had a signifi- cantly greater stand than Terraclor 2E (Table 1). However, by 34 days after planting no significant differences in stand were ob- served among any treatments. Ridomil Gold PC 11G had the most uniform stand with a skip index of 11.5. No differences in maturity were observed as measured by the percent open bolls (Table 2). Seed cotton yields ranged from 3,259.7 pounds per acre to 2,2214.3 pounds per acre for the Ridomil Gold PC 11 G and Terraclor 2E treatments, respectively (Table 2). There were no significant differences in yields among treatments including the control. TABLE 1. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON COTTON STAND, SKIP INDEX, AND PLANT VIGORAT20 A ND 34 DAYS AFTER PLANTING Treatment Rate Emergence/ Emergence/ Skip Vigor 10 ft of row 25 ft of row index rating 20 DAP 34 DAP 34 DAP 34 DAP Untreated control 4.8 ab 7.5 a 20.3 c 1.8 b Terraclor Super X 18.8 G 7.0 Ibs/ac 7.0 ab 8.0 a 21.5 c 1.9 b Terraclor Super X 18.8 G 5.5 Ibs/ac 8.3 ab 9.5 a 20.0 c 1.9 b Terraclor Super X G/ WGB 49 7.4 Ibs/ac 5.3 ab 6.3 a 30.0 ab 1.9 b Terraclor Super X G/WGB 49 5.5 Ibs/ac 7.0 ab 9.0 a 22.3 bc 2.0 ab Terraclor Super X EC 64 oz/ac 6.3 ab 8.0 a 17.8 cd 1.8 b Ridomil Gold PC 11G 7.0 lbs/ac 6.0 ab 9.5 a 11.5 d 1.5 b Rovral 4F 5.3 oz/ac 8.5 a 9.3 a 24.3 abc 1.9 b Terraclor 2E 48 fi oz/ac 3.0 b 4.0 a 32.0 a 2.5 a Terraclor 15G 5.0 Ibs/ac 10.0 a 9.0 a 22.3 bc 1.7 b LSD (0.05) 5.4 5.6 8.4 0.5 Means with the same letter are not significantly different at p=0.05. TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control - 63.5 a 2954.8 abc Terraclor Super X 18.8 G 7.0 Ibs/ac 62.6 a 2860.4 abc Terraclor Super X 18.8 G 5.5 Ibs/ac 61.4 a 2889.5 abc Terraclor Super X G/ WGB 49 7.4 Ibs/ac 55.2 a 2541.0 cd Terraclor Super X G/WGB 49 5.5 Ibs/ac 62.5 a 2679.0 bc Terraclor Super X EC 64 oz/ac 54.6 a 3012.9 ab Ridomil Gold PC 11G 7.0 Ibs/ac 55.0 a 3259.7 a Rovral 4F 5.3 oz/ac 56.3 a 2962.1 abc Terraclor 2E 48 fl oz/ac 55.9 a 2214.3 d Terraclor 15G 5.0 Ibs/ac 55.5 a 3071.0 ab LSD (0.05) . 12.2 434.3 Means with the same letter are not significantly different at p=0.05. 1999 COTTON RESEARCHREPORT 37 EVALUATION OF TERRACLOR AND ROVRAL FOR CONTROL OF SEEDLING DISEASE OF COTTON IN NORTH ALABAMA Kathy S. McLean and William S. Gazaway The objective of this research was to evaluate Terraclor and Rovral in-furrow fungicide sprays for control of Rhizoctonia solani and Pythium spp. seedling disease of cotton. All fungi- cides were applied as an in-furrow spray application at planting. Each plot was infested with Pythium spp. and R. solani by ap- plying inoculated millet seed in the furrow at planting. Plots were planted at the Tennessee Valley Research and Extension Center with Deltapine NuCotn 33B on April 21. Plots consisted of two rows, 25 feet long and 40 inches wide. Plots were arranged in a randomized complete block design with four replications. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension Sys- tem. Stand counts were collected on May 12 and May 25. Plant maturity was estimated by the percent of open bolls on Septem- ber 10 and harvested September 28. Data were subjected to sta- tistical analysis appropriate for the experimental design used and means were separated using the least significant difference test. All statistical tests were performed at the 5% level of significance. At 21 and 34 days after planting, all fungicide treatments produced significantly greater stands than the control (Table 1). Terraclor 15G produced the greatest stand at 2.38 plant per foot of row and the control produced the lowest with 0.25 plant per foot of row at 35 days after planting, respectively. All fungicides produced significantly lower skip indices than the control. No differences in maturity were observed as measured by the percent open bolls (Table 2). Seed cotton yields ranged from 3,627.9 pounds per acre to 2,044.1 pounds per acre for the Terraclor 15G and the control treatments, respectively (Table 2). All fungicide treatments produced significantly greater yields than the control. TABLE 1. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON COTTON STAND, SKIP INDEX, AND PLANT VIGOR AT 21 AND 34 DAYS AFTER PLANTING Treatment Rate Emergence/ Emergence/ Skip Vigor 10 ft of row 25 ft of row index rating 21 DAP 34 DAP 21 DAP 34 DAP Untreated control 3.5b 6.3 c 37.0 a 3.3 a Terraclor 2E 48 fl oz/ac 21.5 a 52.3 ab 9.0 bc 1.9 b Terraclor 15G 5 Ibs/ac 27.5 a 59.5 a 5.3 c 1.9 b Rovral 4F 5.2 oz/ac 23.0 a 38.5 b 13.0 b 1.6 b LSD (0.05) 16.4 17.8 6.9 0.6 Means with the same letter are not significantly different at p=0.05. TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control - 47.3 a 2044.1 b Terraclor 2E 48 fl oz/ac 59.6 a 3425.4 a Terraclor 15G 5 lbs/ac 64.1 a 3627.9 a Rovral 4F 5.2 lb/ac 58.7 a 3236.0 a LSD (0.05) 15.4 534.4 Means with the same letter are not significantly different at p=0.05. 38 ALABAMAAGRICULTURALEXPERIMENT STATION EVALUATION OF QUADRIS FOR CONTROL OF SEEDLING DISEASE OF COTTON IN SOUTH ALABAMA Kathy S. McLean and William S. Gazaway The objective of this research was to evaluate Quadris as an in-furrow fungicide spray and seed treatment for control of seed- ling disease of cotton. All fungicides were applied either as a seed treatment before planting or as an in-furrow spray at planting. Each plot was infested with Pythium spp. and Rhizoctonia solani by applying inoculated millet seed in the furrow at planting. Plots were planted at the Wiregrass Research and Extension Center with Deltapine NuCotn 35B on April 23. Plots consisted of two rows, 25 feet long and 40 inches wide. Plots were arranged in a randomized complete block design with five replications. All plots were maintained throughout the season with standard herbi- cide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Stand counts were collected on May 13 and May 27. Plant maturity was estimated by the percent of open bolls on Septem- ber 16. Plots were harvested on September 29. Data were sub- jected to statistical analysis appropriate for the experimental de- sign used and means were separated using the least significant TABLE 1. EFFECT OF QUADRIS ON COTTON STAND, SKIP I 20 AND 34 DAYS AFTER PLANTI Treatment Rate Emergence/ lO ft of row difference test. All statistical tests were performed at the 5% level of significance. Significant differences in seedling stand were observed at 20 and 34 days after planting. At 20 days after planting, Quadris, Terraclor, Ridomil + Terraclor and the Protege + Allegiance + Quadris treatments produced significantly greater stands than the black seed control and the Protege + Allegiance + Ascend seed treatment (Table 1). By 34 days after planting, the Quadris in- furrow treatments produced a significantly greater stand than the Protege + Allegiance + Quadris seed treatment (Table 1). The skip index rating at 20 days after planting found all Quadris, Terraclor, Ridomil + Terraclor, and Protege + Allegiance + Quadris treatments produced significantly more uniform stands than the black seed control and the Protege + Allegiance + As- cend seed treatment (Table 1). No differences in the percent of open bolls were observed (Table 2). Seed cotton yields ranged from 1,858.6 pounds per acre to 1,488.3 pounds per acre for the Protege + Allegiance + Ascend and Protege + Alle- giance + Quadris treatments NDEX, AND PLANT VIGOR AT respectively (Table 2). There NG were no significant differ- Emergence/ Skip Vigor ences in yield among treat- 25 ft of row index ratina ments including the control. 20 DAP 34 DAP 20 DAP 34 DAP Untreated control (black seed) - 11.0 b 23.0 c 24.5 a 2.6 a Quadris 5.56 fl oz/ac 36.3 a 73.3 a 3.0 b 1.7 b Quadris 8.35 fl oz/ac 36.0 a 73.5 a 1.8 b 1.7 b Terraclor 7.4 fl oz/1000 ft 38.8 a 69.0 ab 2.0 b 2.2 ab Ridomil + Terraclor 0.75 oz/1000 ft + 30.0 a 59.5 b 4.8 b 1.8 ab 7.4 fl oz/1000 ft Protege + Allegiance + Ascend' 40 ppm + 0.75 fl oz/cwt 15.5 b 28.8 c 18.5 a 2.2 a Protege + Allegiance + Quadris' 40 ppm + 0.75 fi oz/cwt 33.3 a 56.8 b 5.0 b 1.8 ab LSD (0.05) 12.6 12.9 9.2 0.8 Seed treatment. Means with the same letter are not significantly different at p=0.05. TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control (black seed) - 54.3 a 1640.8 a Quadris 5.56 fl oz/ac 56.8 a 1844.0 a Quadris 8.35 fl oz/ac 50.5 a 1611.7 a Terraclor 7.4 fl oz/1 000 ft 54.2 a 1786.0 a Ridomil + Terraclor 0.75 oz/1 000 ft+ 52.8 a 1539.1 a 7.4 fl oz/1000 ft Protege + Allegiance + Ascend' 40 ppm + 0.75 fl oz/cwt 62.0 a 1858.6 a Protege + Allegiance + Quadris' 40 ppm + 0.75 fl oz/cwt 46.9 a 1488.3 a LSD (0.05) 18.9 585.3 1 Seed treatment. Means with the same letter are not significantly different at p=0.05. 1999 COTTON RESEARCHREPORT 39 EVALUATION OF QUADRIS FOR CONTROL OF SEEDLING DISEASE OF COTTON IN CENTRAL ALABAMA Kathy S. McLean and William S. Gazaway The objective of this research was to evaluate Quadris as an in-furrow fungicide spray and seed treatment for control of seed- ling disease of cotton. All fungicides were either applied as a seed treatment before planting or as an in-furrow spray at planting. Each plot was infested with Pythium spp. and Rhizoctoniasolani by applying inoculated millet seed in the furrow at planting. Plots were planted at the Prattville Research Field with Deltapine DP 436RR on April 14. Plots consisted of two rows, 25 feet long and 40 inches wide. Plots 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 Sys- tem. Stand counts were collected on May 4 and May 18. Plant maturity was estimated by the percent of open bolls on Septem- ber 9. Plots were harvested on September 28. Data were sub- jected to statistical analysis appropriate for the experimental de- sign used and means were separated using the least sig- nificant difference test. All statistical tests were per- formed at the 5% level of sig- nificance. Significant differences in seedling stand were ob- served at 20 and 34 days af- ter planting. At 20 days after planting, Quadris at 5.56 fluid ounces per acre produced a significantly greater stand than the black seed control and Quadris at 8.35 fluid ounces per acre (Table 1). By 34 days after planting Quadris at 5.56 fluid ounces per acre and Ridomil + Terraclor produced a significantly greater stand than all other treatments (Table 1). The skip index rating at 20 days after planting found Quadris at 5.56 fluid ounces per acre, Terraclor, Ridomil + Terraclor, Protege + Allegiance + Ascend, and Protege + Alle- giance + Quadris treatments produced significantly more uniform stands than the black seed control and Quadris at 8.35 fluid ounces per acre (Table 1). No differences in the percent of open bolls were observed between fungicide treatments and the control (Table 2). Seed cot- ton yields ranged from 3,659.1 pounds per acre to 1,248.7 pounds per acre for the Quadris at 5.56 fluid ounces per acre and the black seed control treatments, respectively (Table 2). All fungi- cide treatments produced significantly greater yields than the black seed control and the Protege + Allegiance + Ascend seed treat- ment. TABLE 1. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON COTTON STAND, SKIP INDEX, AND PLANT VIGOR AT 20 AND 34 DAYS AFTER PLANTING Treatment Rate Emergence/ Emergence/ Skip Vigor 10 ft of row 25 ft of row index rating 20 DAP 34 DAP 20 DAP 34 DAP Untreated control (black seed) - 5.0 b 4.0 c 35.3 a 2.8 a Quadris 5.56 fl oz/ac 11.5 a 16.0 a 6.5 b 1.6 b Quadris 8.35 fl oz/ac 6.0 b 4.0 c 28.0 a 2.1 ab Terraclor 2E 7.4 fl oz/1000 ft 7.3 ab 9.5 b 16.3 b 1.9 b Ridomil + Terraclor 0.75 oz/1000 ft+ 7.4 fl oz/1000 ft 8.3 ab 15.8 a 6.3 b 1.5 b Protege + Allegiance + Ascend' 40 ppm + 0.75 fl oz/cwt 7.0 ab 9.0 bc 12.8 b 1.9 b Protege + Allegiance + Quadris' 40 ppm + 0.75 fl oz/cwt 8.0 ab 11.0 ab 10.0 b 1.8 b LSD (0.05) 4.6 5.5 10.9 0.8 SSeed treatment. Means with the same letter are not significantly different at p=0.05. TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control (black seed) - 54.1 ab 1248.7 e Quadris 5.56 fl oz/ac 51.2 b 3659.1 a Quadris 8.35 fl oz/ac 50.4 b 2780.6 cd Terraclor 7.4 fl oz/1000 ft 55.2 ab 3121.8 bc Ridomil + Terraclor 0.75 oz/1000 ft+ 7.4 fi oz/1000 ft 58.6 ab 3317.8 ab Protege + Allegiance + Ascend' 40 ppm + 0.75 fl oz/cwt 56.6 ab 2606.4 d Protege + Allegiance + Quadris' 40 ppm + 0.75 fl oz/cwt 63.4 a 3230.7 abc LSD (0.05) 12.8 462.0 'Seed treatment. Means with the same letter are not significantly different at p=0.05. 40 ALABAMAAGRICULTURALEXPERIMENT STATION 1999 COTTON RESEARCH REPORT EVALUATION OF QUADRIS FOR CONTROL OF SEEDLING DISEASE OF COTTON IN NORTH ALABAMA Kathy S. McLean and William S. Gazaway The objective of this research was to evaluate Quadris as an in-furrow fungicide spray and seed treatment for control of seed- ling disease of cotton. All fungicides were either applied as a seed treatment before planting or as an in-furrow spray at planting. Each plot was infested with Pythium spp. and Rhizoctoniasolani by applying inoculated millet seed in the furrow at planting. Plots were planted at the Tennessee Valley Research and Extension Center with Deltapine DP 436RR on April 21. Plots consisted of two rows, 25 feet long and 40 inches wide. Plots 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. Stand counts were collected on May 12 and May 26. Plant maturity was estimated by the percent of open bolls on Septem- ber 10. Plots were harvested on September 28. Data were sub- jected to statistical analysis appropriate for the experimental de- sign used and means were separated using the least significant difference test. All statistical tests were performed at the 5% level of significance. Significant differences in seedling stand were observed at 21 and 35 days after planting. At 21 days after planting, all Quadris treatments produced a significantly greater stand than the black seed control and Protege + Allegiance + Ascend seed treatment (Table 1). By 35 days after planting Quadris at 8.35 fluid ounces per acre and Protege + Allegiance + Quadris produced a signifi- TABLE 1. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON COTTON STAND, SKIP INDEX, AND PLANT VIGOR AT 21 AND 35 DAYS AFTER PLANTING Treatment Rate Emergence/ 10 ft of row 21 DAP Emergence/ 25 ft of row 35 DAP Skip index 21 DAP Vigor rating 35 DAP Untreated control (black seed) - 5.3 d 8.5 e 37.3 a 3.1 a Quadris 5.56 fl oz/ac 20.3 ab 43.8 b 8.5 de 1.8 d Quadris 8.35 fl oz/ac 27.5 a 53.5 a 8.5 de 1.8 d Terraclor 7.4 fl oz/1000 ft 13.5 bc 40.8 b 12.5 cde 2.2 bcd Ridomil + Terraclor 0.75 oz/1000 ft + 18.0 b 39.5 b 11.3 de 2.3 bcd 7.4 fl oz/1000 ft Protege + Allegiance + Ascend 40 ppm + 0.75 fi oz/cwt 8.5 cd 20.0 d 27.5 b 2.8 ab Protege + Allegiance + Quadris 40 ppm + 0.75 fi oz/cwt 20.8 ab 55.8 a 7.8 e 1.9 cd Ridomil Gold 0.040 lb ai/ac 14.5 bc 26.5 cd 18.0 c 2.6 abc Ridomil Gold + Flint 0.40 Ib aVac + 16.0 bc 29.5 c 14.0 cd 2.3 bcd 0.125 lb al/ac LSD (0.05) 7.8 9.3 5.9 0.7 1 Seed treatment. Means with the same letter are not significantly different at p=0.05. TABLE 2. EFFECT OF SELECTED IN-FURROW FUNGICIDES ON PERCENT OPEN BOLLS AND SEED COTTON YIELD Treatment Rate Open bolls Seed cotton yield % lbs/ac Untreated control (black seed) - 50.9 a 1459.6 d Quadris 5.56 fl oz/ac 58.5 a 3062.9 a Quadris 8.35 fl oz/ac 56.2 a 3164.1 a Terraclor 7.4 fl oz/1000 ft 49.1 a 2997.6 ab Ridomil + Terraclor 0.75 oz/1000 ft + 7.4 fl oz/1000 ft 49.4 a 3040.1 ab Protege + Allegiance + Ascend 1 40 ppm + 0.75 fl oz/cwt 56.3 a 2566.6 c Protege + Allegiance + Quadris 1 40 ppm + 0.75 fl oz/cwt 63.8 a 3262.1 a Ridomil Gold 0.040 lb ai/ac 55.38 a 2703.7 bc Ridomil Gold + Flint 0.40 Ib aVac + 0.125 lb av/ac 53.7 a 2759.2 bc LSD (0.05) 16.8 382.4 1 Seed treatment. Means with the same letter are not significantly different at p=0.05. cantly greater stand than all other treatments (Table 1). All fungicide treatments pro- duced a significantly greater stand than the control. The skip index rating at 21 days after planting found all fun- gicide treatments produced a significantly more uniform stand than the black seed con- trol and the Protege + Alle- giance + Ascend seed treat- ment (Table 1). No differences in the percent of open bolls was ob- served between any treat- ments (Table 2). Seed cotton yields ranged from 3,262.1 pounds per acre to 1,459.6 pounds per acre for the Pro- tege + Allegiance + Quadris and the untreated black seed control treatments, respec- tively (Table 2). All fungicide treatments produced signifi- cantly greater yields than the black seed control. 41 42 ALABAMA AGRICULTURAL EXPERIMENT STATION EVALUATION OF SELECTED FUNGICIDES FOR CONTROL OF COTTON BOLL ROT DISEASE ON Kathy S. McLean and William S. Gazaway A cotton boll rot fungicide test was conducted to determine effects of selected fungicides on cotton boll rot and yield. All fungicides were applied as a foliar spray. Plots were planted at the Gulf Coast Research and Exten- sion Center with Deltapine NuCotn 33B cotton on May 19. Plots were arranged in a randomized complete block design with five replications and consisted of two rows, 40 feet long and 38 inches wide. Alleys were bush hogged to create a 10-foot alley at defo- liation to facilitate harvest. All plots were maintained with stan- dard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Fungicides were applied at full bloom on August 3 and at boll cracking on September 8. Boll rot disease ratings were deter- mined on October 13. Plots were harvested on November 3. Data were subjected to statistical analysis appropriate for the experi- DELTAPINE NuCOTN 33B mental design used and means were separated using the least sig- nificant difference test. All statistical tests were performed at the 5% level of significance. Quadris 2SC, Benlate 50 WP, Tilt, Terraclor 4F, and Rovral 4F all significantly reduced the number of rotted cotton bolls as compared to the control (see table). Cotton boll rot was not sig- nificantly reduced by two applications (full bloom plus boll crack- ing) of any of the fungicides compared to the full bloom and boll cracking single applications. Seed cotton yields ranged from 2,895 pounds per acre to 2,111 pounds per acre for the Rovral 4F ap- plied at full bloom and Benlate 50WP applied at boll cracking, respectively. There were no significant differences in yield among treatments; however, full bloom fungicide applications increased cotton yield an average of 77 pounds per acre compared to the control. EFFECT OF SELECTED FOLIAR FUNGICIDES ON COTTON BOLL ROT AND SEED YIELD Treatment Rate Spray Diseased Seed cotton per acre schedule bolls yield no lbs/ac Quadris 2 SC 0.20 lb Full bloom 56 bc 2608 abc Quadris 2 SC 0.20 lb Full bloom + boll cracking 62 bc 2472 abc Quadris 2 SC 0.20 lb Boll cracking 57 bc 2159 bc Benlate 50WP 0.10 Ib Full bloom 49 bc 2667 ab Benlate 50WP 0.10 Ib Full bloom + boll cracking 52 bc 2190 bc Benlate 50WP 0.10 lb Boll cracking 73 ab 2111 c Tilt 4 oz Full bloom 72 ab 2618 abc Tilt 4 oz Full bloom + boll cracking 59 bc 2348 bc Tilt 4 oz Boll cracking 38 c 2331 bc Terraclor 4F 16 oz Full bloom 59 bc 2254 abc Terraclor 4F 16 oz Full bloom + boll cracking 55 bc 2557 abc Terraclor 4F 16 oz Boll cracking 61 bc 2434 abc Rovral 4F 4 oz Full bloom 44 c 2895 a Rovral 4F 4 oz Full bloom + boll cracking 63 bc 2419 abc Rovral 4F 4 oz Boll cracking 58 bc 2286 bc Untreated control 92 a 2531 abc LSD (0.05) 26.5 526.5 Means with the same letter are not significantly different at p=0.05. 42 ALABAMAAGRICULTURALExPERIMENT STATION 1999 COTTON RESEARCH REPORT EVALUATION OF SELECTED FUNGICIDES FOR CONTROL OF COTTON BOLL ROT DISEASE ON PAYMASTER PM 1220BG/RR Kathy S. McLean and William S. Gazaway A cotton boll rot fungicide test was conducted to determine effects of selected fungicides on cotton boll rot and yield. Fungi- cides were applied as a broadcast spray. The field was not irri- gated. Plots were planted at the Monroeville Research Field with Paymaster PM 1220BG/RR cotton on May 5. Plots were arranged in a randomized complete block design with five replications and consisted of two rows, 40 feet long and 36 inches wide. Blocks were separated by 20-foot alleys. All plots were maintained with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Fungicides were applied at full bloom on August 2 and at boll cracking on September 8. Boll rot disease ratings were deter- mined on October 13. Plots were harvested October 29. Data were subjected to ANOVA appropriate for the experimental design used and means were separated using the least significant difference test. All statistical tests were performed at the 5% level of signifi- cance. Boll rot was not observed due to the intense drought. Seed cotton yields ranged from 1,612 pounds per acre to 1,408 pounds per acre for the Quadris 2SC full bloom application and the Rovral 4F full bloom plus boll cracking application, respectively (see table). There were no signifi- S- . -10, , 0 , - _ - - - * _ , * - 1 - EFFECT OF SELECTED FOLIAR FUNGICIDES ON COTTON BOLL ROT AND SEED YIELD Treatment Rate Spray schedule Seed cotton yield per acre (lbs/ac) Quadris 2 SC 0.20 lb Full bloom 1612 a Quadris 2 SC 0.20 lb Full bloom + boll cracking 1583 ab Quadris 2 SC 0.20 lb Boll cracking 1548 ab Benlate 50WP 0.10 lIb Full bloom 1562 ab Benlate 50WP 0.10 lb Full bloom + boll cracking 1606 ab Benlate 50WP 0.10 lb Boll cracking 1518 ab Tilt 4 oz Full bloom 1562 ab Tilt 4 oz Full bloom + boll cracking 1461 ab Tilt 4 oz Boll cracking 1583 ab Terraclor 4F 16 oz Full bloom 1551 ab Terraclor 4F 16 oz Full bloom + boll cracking 1423 ab Terraclor 4F 16 oz Boll cracking 1493 ab Rovral 4F 4 oz Full bloom 1519 ab Rovral 4F 4 oz Full bloom + boll cracking 1408 b Rovral 4F 4 oz Boll cracking 1528 ab Untreated control 1536 ab LSD (0.05) 200.56 Means with the same letter are not significantly different at p=0.05. cant difftterences in yield among treatments. 43 44 ALABAMA AGRICULTURAL EXPERIMENT STATION DEFOLIANT APPLICATIONS EVALUATION OF FLAIR AS A COTTON Charles Burmester Flair is an endothall salt product that has been formulated for increased effectiveness when used as a cotton defoliant. The objective of this research was to evaluate Flair's effectiveness as a cotton defoliant and boll opening product and determine Flair's usefulness in combination with other cotton defoliants. The cotton variety in this study was Deltapine NuCotn 33B planted at the Tennessee Valley Research and Extension Center, Belle Mina, Alabama. Plots consisted of four rows 30 feet long, arranged in a randomized complete block with four replications. Cotton defoliants (see table) were applied in 10 gallons of spray volume on September 8. Defoliation ratings were taken on Sep- tember 13, September 15, and September 22. Percent open bolls were determined on September 8, September 15, and September 22. Terminal and basal regrowth were determined three weeks after application, and yields were determined by mechanically picking the two center rows of each plot. DEFOLIANT Due to hot, dry weather all defoliants worked quickly and defoliation was generally good (see table). Two days after appli- cation it appeared many leaves were desiccated and might not fall off the plants. These leaves, however, did fall off quickly and desiccation was not a problem. Flair at two pints per acre numeri- cally enhanced defoliation in combination with the Def/Folex mixture. The combination of Flair (one pint) and Ginstar (five ounces), however, had the highest defoliation rating. In most treat- ments some green immature leaves were left in the top of the plants, which resulted in the lower ratings. Differences in cotton boll opening were difficult to deter- mine because of the rapid maturity of this cotton crop. Treat- ments had little effect on boll opening under these hot dry condi- tions. Regrowth was also very low due to the hot dry weather (see table). Small differences in yields were determined to be caused by small elevation differences in the field. EFFECT OF FLAIR ON DEFOLIATION, OPEN BOLLS, REGROWTH, AND YIELD Treatment Rate -Percent defoliation- -Percent open bolls- -Regrowth- Yields per acre Sept. 13 Sept. 15 Sept. 22 Sept. 8 Sept. 15 Sept. 22 top base lbs/ac Def/Folex 0.75 pt 81.7 ab 90.0 ab 93.3 cd 63.0 ab 96.7 ab 100.0 a 0.0 a 16.7 a 2002 bcd Def/Folex + Flair 0.75 + 2.0 pt 85.0 a 95.0 a 95.0 bc 69.3 a 95.0 ab 97.8 ab 0.0 a 6.7 ab 1980 cd Def/Folex + Flair 0.75 + 1.0 pt 80.0 ab 91.7 ab 93.3 cd 65.0 ab 98.3 a 98.3 0.0 a 3.3 ab 2144 a-d Def/Folex + Finish 0.75 + 0.5 pt 81.7 ab 88.3 ab 90.0 def 55.6 ab 97.9 a 98.6 ab 0.0 a 0.0 b 1857 d Def/Folex + Prep 0.75 + 1.33 pt 76.7 ab 90.0 ab 91.7 cde 57.0 ab 99.1 a 100.0 a 0.0 a 5.0 ab 2013 bcd Def + Prep 0.75 + 0.5 pt 73.3 bc 85.0 bc 88.3 ef 47.3 b 85.2 b 92.9 b 0.0 a 3.3 ab 2050 bcd Finish 1.5 pt 76.7 ab 83.3 bc 86.7 f 62.7 ab 91.3 ab 94.8 ab 0.0 a 5.0 ab 2020 bcd Finish + Flair 1.5+ 1.0 pt 76.7 ab 85.0 bc 93.3 cd 59.4 ab 91.6 ab 95.1 ab 0.0 a 1.7 ab 2260 abc Ginstar 5 oz 66.7 c 79.3 c 98.3 ab 52.8 ab 91.8 ab 97.1 ab 0.0 a 0.0 b 2278 ab Ginstar + Flair 5 oz + 1.0 pt 81.7 ab 95.0 a 100.0 a 57.2 ab 93.9 ab 97.7 ab 0.0 a 3.3 ab 2373 a LSD (0.10) 7.67 7.46 4.11 16.56 10.51 6.03 0.00 13.98 258.3 Means with the same letter are not significantly different at the p=0.10 level. ALAE3AMAAGRICULTURAL -EXPERIMENT STATION 44 1999 COTTON RESEARCH REPORT EVALUATION OF GINSTAR AS A COTTON DEFOLIANT Charles Burmester Ginstar is a combination of the defoliant Dropp and the her- bicide Diuron. It is formulated as a liquid product. The objective of this study was to evaluate how Ginstar could best fit into a cotton defoliation program. The cotton variety Deltapine NuCotn 33B was planted at the Tennessee Valley Research and Extension Center, Belle Mina, Alabama. Plots consisted of four rows 30 feet long arranged in a randomized block with four replications. Treatments (see table) were applied in 10 gallons of spray volume on August 23. Defo- liation ratings were made on August 27, August 30, and Septem- ber 6. Percent open bolls were counted on August 23, August 27, and September 6. Terminal and basal regrowth ratings were made three weeks after treatment, and yields were determined by me- chanically picking the two center rows of each plot. The combination of Ginstar (six ounces) and Finish (32 ounces) had the highest early defoliation ratings (see table). How- ever, after 14 days all treatments had similar ratings. Due to hot dry condition many upper bolls on the cotton were shed and cot- ton matured very quickly. Under these conditions all defoliation product produced similar results. Percent open bolls and regrowth ratings were also very simi- lar for all defoliant tests (see table). Yields (see table) were slightly higher where Ginstar was used alone, but this was determined to be caused by small elevation differences in the trial area. EFFECT OF GINSTAR ON DEFOLIATION, OPEN BOLLS, REGROWTH, AND YIELD Treatment Rate -Percent defoliation- -Percent open bolls- -Regrowth- Yields per acre Aug. 27 Aug.30 Sept. 6 Aug.23 Aug.27 Sept. 6 top base lbs/ac Ginstar 6 oz 63.8 b 83.8 b 93.8 a 76.7 a 91.1 a 98.4 a 0.0 a 0.0 d 2102 a Ginstar 8 oz 67.5 ab 82.5 b 95.0 a 68.8 a 93.1 a 100.0 a 1.3 a 2.5 cd 2005 ab Ginstar + Prep 6oz + 21 oz 66.3 ab 82.5 b 95.0 a 68.2 a 87.8a 100.0 a 1.3a 7.5 ab 1958 b Ginstar + Finish 6 oz + 32 oz 76.3 a 95.0a 93.8 a 76.4 a 90.9 a 100.0 a 0.0 a 10.0 a 1944 b Ginstar + Harvade + 6 oz + 8 oz + 63.8 b 83.8 b 91.3 a 72.8 a 89.8 a 99.4 a 2.5 a 6.3 abc 1930 b Crop Oil 16 oz Ginstar + Crop Oil 6 oz + 16 oz 67.5 ab 85.0 b 93.8 a 71.8 a 88.4 a 98.2 a 0.0 a 5.0 bc 1933 b LSD (0.10) 9.69 7.27 3.52 12.69 11.73 1.72 2.36 3.80 109.1 Means with the same letter are not significantly different at the p=0.10 level. 45 MOLECULAR STUDIES EVOLUTIONARY DIVERSITY OF CELLULOSE SYNTHASE (CESA) IN GossYPIUM Aaron Jeffries, Allan Zipf, Khairy Soliman, Johnie Jenkins, S. Saha, and Deborah Delmer The overall goal of this multi-laboratory project was to study the evolution and diversity of one of the most important gene families in plants, cellulose synthase, specifically, the catalytic subunit of cellulose synthase (CesA) which makes the glucose polymer we call cellulose. Cell walls of plants are primarily made up of cellulose and so CesA is thought to be an important enzyme for all plants. One aspect of this project was to investigate the CesA fam- ily in cotton, the fibers of which are almost pure cellulose. In the first step, the CesA primers were used to screen two to three rep- resentatives from each assumed ancestor species as well as from the current cultivated species in an evolutionary/taxonomic sur- vey. Researchers then tried to identify which chromosomes these CesA genes were located on. Good quality genomic DNA has been extracted from several ancestral and modem species. Using a molecular technique, similar to that used in forensics, research- ers amplified the DNA in a polymerase chain reaction (PCR) us- ing primers designed at the University of California-Davis. Sev- eral other primers, based on similarities in their DNA, have been selected and are being evaluated for their utility in detecting gene differences. INDUCTION OF HIGHLY EMBRYOGENIC CALLI AND PLANT REGENERATION IN DIPLOID AND TETRAPLOID COTTONS H. F. Sakhanokho, Alan Zipf, Govind C. Sharma, Mehmet Karaca, S. Saha, and K. Rajasekaran Successful plant transformation depends on regeneration of plants from transformed cells. The current commercial transgenic cottons were derived from COKER cultivars. This lack of vari- ability in transgenic cotton could potentially contribute to a nar- row genetic base. Therefore, there is a need to broaden the num- ber of regenerable cotton lines. Through a combination of tech- nique, media, and timely manipulations, researchers have devel- oped a method to produce large numbers of somatic embryos (SEs) in two tetraploid as well as in two diploid accessions. SEs are just like zygotic embryos found in a seed except these de- velop from cells other than a fertilized egg. SEs germinate and give rise to plants, just like zygotic embryos, only SEs are pro- duced by tissue culture means. Callus, an unorganized mass of cells, was started from pieces of seedling stem or leaf and transferred, within a critical time frame, to a callus proliferation/maintenance medium. Potential embryogenic calli were then identified and transferred to liquid culture for four weeks, strained through a mesh screen to enrich for embryogenic cells, and placed on an embryo development/ maturation medium. Large numbers of somatic embryos were reproducibly developed from all these lines. Mature SEs, placed on medium with no hormones, germinated and produced plants. Plant regeneration efficiency was improved by a combina- tion of media compositions from cultures of different ages. In addition, genetic changes due to the culturing process (known as "somaclonal variation") were also investigated. Preliminary molecular analysis indicated little somaclonal variation due to the culturing process. This report offers, for the first time, a reliable and reproduc- ible method to obtain regenerable and highly embryogenic lines in ancestral Gossypium species as well as modem commercial lines that can be utilized for development of transgenic plants. In addition, the method has the potential for improving plant production from other commercial cotton lines that are difficult to culture. trlmlllL~E In nl~nta r~lll~l~aP a~mtk~crCI Qnprltlr~llr~ tZ1~ rQtQI~Rlr KPQP~r(rC~PrQ 46 ALABAMAAGRICULTURAL'ExPERIMENT STATION 1999 CanoN RESEARCH REPORT 47 AUTHORS' INDEX Author, Page James R. Akridge Jim Bannon U. R. Bishnoi Charles Burmester E. Cebert Richard L. Davis Dennis P. Delaney Deborah Delmer David Derrick B. Durbin Barry L. Freeman Brian Gamble William S. Gazaway Aaron Jeffries Johnie Jenkins Mehmet Karaca Kathy S. McLean Charles C. Mitchell William J. Moar C. Dale Monks Don P. Moore Gary L. Mullen Bobby E. Norris Michael G. Patterson K. Rajasekaran Wayne Reeves S. Saha Hamidou F Sakhanokho Govind C. Sharma Ron H. Smith Khairy Soliman Glenn Wehtje Rob Woods Allen Zipf 29-30, 31 2,4, 6 1-2 1, 3, 5-6, 13, 27, 44, 45 1-2 21-23,24,25-26 2, 44, 4,6, 13 46 2, 4, 6 14-15, 18-19, 19-21 4 29-30, 31, 32-33, 33-34, 34-35, 36, 37, 38, 39, 40, 41, 42, 43 46 46 46 29-30, 31, 32-33, 33-34, 34-35, 36, 37, 38, 39, 40, 41, 42, 43 7-8, 9-10, 11-12 25 2,4,4,6, 13 2 11-12 13 27-28,28 46 4 46 46 46 15-16, 16-17, 21-23, 24, 25, 25-26 46 13 13 46 1999 COTTON RESEARCHREPORT 47 Alabama's Agricultural Experiment Station System AUBURN UNIVERSITY ( Main Agricultural Experiment Station, Auburn. LIMESTONE MADISON JACKSON Alabama A&M University = E. V. Smith Research Center, Shorter. MORG MARSHALL DE KALB CE 2 1. Tennessee Valley Research and ETOWAHExtension Center, Belle Mina. BLOUNT 2. Sand Mountain Research and Extension CALHOUNCenter, Crossville. JEFFERSON SANTCLdR 3. North Alabama Horticulture Station, TALLEDEGA CLEBURNE Cullman. ELBY CLAYDO4. Upper Coastal Plain Research Station, Winfield. COOSA TALLAP CHAMBER 5. Chilton Area Horticulture Station, 5 6 Clanton. 6. Piedmont Research Station, Camp Hill. AUTAUGA LMORE7. Prattville Experiment Field, Prattville. 7 MACON RUSSELL 8. Black Belt Research and Extension SMONTGOMER Center, Marion Junction. DALLAS 9. Lower Coastal Plain Research Station, Camden. L 10. Monroeville Experiment Field, OE HENRYMonroeville. CONECUH CRENSH COFFEE DALE 11. Wiregrass Research and Extension COVINGTOCenter, Headland. GENEVA HOUSTo 12. Brewton Experiment Field, Brewton. 213. Ornamental Horticulture Station, Spring Hill. 14. Gulf Coast Research and Extension Center, Fairhope.