1995 QRNAMENTALS RESEARCH REPORT K JLA J -, -~ ,- t r CONTENTS GREENHOUSE CROPS Broiler Litter Affects Growth of Annuals and Perennials ............................................................................... 2 Landscape Performance of Fall and Summer Annuals ............................................. .......... 3 National Bedding Plant Production Increasing ............................. .......... ........................ 6 Consumer Preferences for Geranium Flower Color, Leaf Variegation, and Price........................... 8 INSECT, DISEASE, AND WEED CONTROL Crapemyrtle Cultivars Resistant to Powdery Mildew ..................................................................................... 9 Application of Pesticides and Pesticide Combinations for Control of Liriope Scale on Container-Grown Liriope ..................................................................................... 10 Managing Boxwood Leafminer in Containerized Boxwood .......................................................................... 11 Fireblight-Resistant Crabapple Cultivars ........................................................................................................ 13 Evaluation of Selected Herbicides on Field-Grown Woody Plants............................14 Adsorption, Desorption, and Leaching of Oryzalin in Container Media and Soil ................ 16 Evaluation of Selected Fungicides for Control of Southern Blight on Aucuba ................................... 17 Evaluating Phytotoxicity of Insecticidal Oil Sprays on Selected Container-Grown Plants..............18 Granular Preemergence Herbicides Influence Annual Bedding Plant Growth ................................ 20 Herbicide-Coated or -Blended Fertilizers Control Weeds and Reduce Pesticide Runoff .......... 22 Reaction of Dogwood Selections to Powdery Mildew ..................................................... 24 Southern Red Mite Control on Azalea ....................................................................................................... 25 Pesticides to Control Crapemyrtle Aphids ................................................................................................ 26 Pesticides to Control Azalea Lacebugs ..................................................... 26 Evaluation of Selected Fungicides for Control of Photinia Leafspot .......... ............ .............. 27 WOODY ORNAMENTALS Chemically Induced Branching of Vinca Minor ........................................................................................... 28 BA-Induced Offset Formation in Hosta ......................................................................................................... 30 Offset Stage of Development Affects Hosta Propagation by Stem Cuttings ........................................ 32 Growth and Flowering Response of Butterfly-Bush toCutless .................................................................... 34 Growth Control of Asiatic Jasmine and Carolina Jessamine ............................................................. 36 Cutless Controls Shoot Growth of 'China Girl' Holly ........................ ................................................. 38 Foliage Characteristics of Selected Red MapleCultivars ............................................................................. 40 Red Maple Cultivar Performance in the Southeast ....................................................................................... 41 Buddleia Varieties Root Differently in Response to Rooting Hormone ................................................ 44 Comparison of Buddleia Cultivars as Cut Flowers ......................................................................................... 45 Response of 'Prize' Azalea to Sumagic Applied at Several Stages of Shoot Apex Development ............ 47 Survey of Preferences for Alternative Christmas Trees .............................................................................. 49 FIRST PRINTING 3M, OCTOBER 1995 NOTE: This publication reports the results of research only It does not imply registration of a pesticide nor is it intended as an endorse- ment of any named product. Before using any of the products mentioned in this research paper, be certain of their registration by appropriate state and/or federal authorities. Information contained herein is available to all without regard to race, color sex, or national origin. James R. Akridge Superintendent Brewton and Monroeville Experiment Fields Virginia V. Allen Graduate Research Assistant Horticulture Bridget K. Behe Associate Professor Horticulture Greg Creech Technician Horticulture Cynthia K. Crossan Graduate Research Assistant Horticulture Zandra DeLamar Technician Entomology William A. Dozier Professor Horticulture Donald J. Eakes Associate Professor Horticulture Frederick W. Engle Technician Ornamental Horticulture Substation James T. Foley Graduate Research Assistant Horticulture William J. Foster Former Superintendent Ornamental Horticulture Substation Mary K. Gaylor Technician Horticulture Charles H. Gilliam Professor Horticulture Austin K. Hagan Professor Horticulture AUTHORS Ben J. Hajek Professor Agronomy and Soils Charles P. Hesselein Horticulturist Ornamental Horticulture Substation Gregory S. Hodges Graduate Research Assistant Entomology Kevin R. Keel Graduate Research Assistant Horticulture Gary J. Keever Professor Horticulture Tammy S. Krentz Graduate Research Assistant Horticulture C. Chris Montgomery Graduate Research Assistant Horticulture Robert G. Nelson Associate Professor Agricultural Economics and Rural Sociology John W. Olive Superintendent Ornamental Horticulture Substation John T. Owen Superintendent Piedmont Substation Patrick Pace Graduate Research Assistant Horticulture Leonard C. Parrott, Jr. Technician Ornamental Horticulture Substation Curt M. Peterson Professor Botany and Microbiology J. Heath Potter Graduate Research Assistant Horticulture Jesse A. Reeder Graduate Research Assistant Horticulture William H. Reynolds Graduate Research Assistant Entomology Jeff L. Sibley Research Assistant Horticulture James C. Stephenson Associate Superintendent Ornamental Horticulture Substation David B. South Professor Forestry Mack Thetford Graduate Research Assistant Horticulture Kenneth M. Tilt Associate Professor Horticulture Catherine M. Walker Research Assistant Horticulture Glenn R. Wehtje Professor Horticulture James B. Witt Superintendent E.V. Research Center Horticulture Unit J. David Williams Assistant Professor Horticulture Michael L. Williams Associate Professor Entomology For more information, call Robyn Hearn at the Alabama Agricultural Experiment Station Office of Research Information at (334) 844-4877. 2 ALABAMA AGRICULTURAL EXPERIMENT STATION GREENHOUSE CROPS Broiler Litter Affects Growth of Annuals and Perennials VIRGINIA V. ALLEN AND BRIDGET K. BEHE Disposal of broiler litter, an organic waste by- product of the poultry industry, has become more chal- lenging in light of increased scrutiny of its potential to pollute ground and surface water. Since poultry ma- nure contains organic forms of nitrogen, it can be composted and used as a supplement in commercial fertilizers and as a substitute for peat moss in soilless growing media. An Alabama Agricultural Experiment Station (AAES) study was conducted to determine growth ef- fects of two annual and two perennial plant species grown in media amended with broiler litter compost. Growth of annuals was reduced when composted lit- ter was added to the media, while growth of perenni- als was minimally affected. METHODS Media were developed to resemble a commercially available peat-lite mix by blending composted litter, peat moss, and perlite. Four media were used, each with increasing amounts of litter compost; the lowest litter concentration was in a mix with one part litter, three parts peat, and four parts perlite (1:3:4). Other litter:peat:perlite combinations were 2:2:4, 3:1:4, and 4:0:4. Plants grown in these media were compared to plants grown in a commercially prepared peat-lite medium, Fafard #2. Plugs of annuals Impatiens wallerana 'Accent Li- lac' and Capsicum fruitescens 'Bonnie Bell' and pe- rennials Salvia farinacea 'Victoria' and Coreopsis grandiflora 'Early Sunrise' were transplanted on Feb. 15, 1994, into four-inch square plastic pots. Trans- plants were placed in a polyethylene-covered green- house, grown for six weeks using standard cultural practices, and fertilized with 27 ounces per 100 gal- lons of water of 20N-8.7P-16.6K Prosol at each irri- gation. Plants were irrigated as needed. RESULTS Impatiens were smaller when grown in media con- taining broiler litter compost. The addition of any amount of composted litter significantly reduced the fresh and dry weight of impatiens when compared to plants grown in Fafard #2. Height of impatiens was shortest in the 2:2:4 medium (see table). Growth indi- ces for impatiens in 2:2:4 and 4:0:4 media were smaller than those for impatiens grown in Fafard #2. Growth index is determined by adding the height, the width at the widest point, and the width perpendicular to the widest point, and then dividing that number by three. 'Bonnie Bell,' a pepper plant, showed similar reduc- tion in growth, height, fresh, and dry weight. Salvia was affected minimally by the addition of composted litter to the medium (see table). The growth index for salvia grown in 4:0:4 media was somewhat smaller when compared to the Fafard treatment. Height, fresh weight, and dry weight were not affected by the use of litter in the media. Coreopsis was not affected by the addition of composted litter to the media. The two annual species did not grow as well in media with litter. Other annual and perennial plant species should be tested at different rates using com- post prior to larger-scale production in media contain- ing composted litter. Broiler litter could be used as an amendment in perennial plant production. 1995 ORNAMENTALS RESEARCH REPORT 3 Landscape Performance of Fall and Summer Annuals BRIDGET K. BEHE, CATHERINE M. WALKER, C. CHRIS MONTGOMERY, JAMES B. WITT, AND J. DAVID WILLIAMS Approximately 120 annual plant cultivars were observed from the fall of 1993 through the spring of 1994 in the All-America Selections Display Garden at the E.V. Smith Research Center in Shorter. In sum- mer 1994, 270 bedding plant cultivars were evaluated in the display garden. Objectives of the studies were to assist Alabama horticultural professionals and con- sumers in plant selection by determining the winter tolerance of fall-flowering plants and the heat toler- ance of summer-flowering plants. In the fall test, pansies performed well through- out the fall and winter. Alternatives to pansies for the fall landscape, and nice complimentary plants, include ornamental cabbage and kale. All cultivars tested per- formed relatively well during the coolest part of the winter. Dianthus cultivars tested performed well in the early spring, but not through the fall and winter months. In the summer test, Salvia coccinea 'Lady in Red' was the best-performing full-sun cultivar. This excep- tional plant performed well throughout the season, providing color and texture to the landscape. METHODS Seeds of the entries were donated by several com- panies and grown by a local commercial transplant producer. Beds were located in Norfolk-Orangeburg loamy sand association (fine, loamy, siliceous, ther- mic Typic Kandiudults) soil, tilled, and then fumigated with methyl bromide two weeks before planting. Black plastic mulch covered the beds in the fall study. In both studies, 12 plants per entry were spaced nine inches on center in a double row. Ornamental kale in the fall study was spaced 15 inches on center. Fall transplants were planted on Nov. 8, 1993; summer transplants, May 15, 1994. Fall plants were drip irrigated with 200 parts per million of nitrogen using 20N-8.7P-16.6K Peter's fer- tilizer as needed until March 23, 1994. In the summer study, a commercially available controlled release fer- tilizer (18N-5.2P-10K) was preplant incorporated into the beds at a rate of five pounds per 100 square feet; no additional fertilizer was added during the season. Most plants were grown in full sun. Impatiens were grown under aluminum hoop frames covered with 60% black shade fabric in the summer study. In the summer study, rainfall was supplemented by overhead sprinkler irrigation to provide an equivalent of one inch of water per week. In general, June and July were cloudier and rainier than normal, but August and Sep- tember were sunnier and drier than normal. Eight of twelve plants per entry were evaluated twice monthly from Dec. 6 through March 21 in the fall study and from June 23 through Sept. 29. in the summer study. The outer four plants on each side of the test plants were used as guard rows. Plants were rated by the same individual using a scale of 1-5 (see tables for definition of scale). Flowering plants were rated primarily on their floral displays, while size, shape, and freedom from insect or disease blemishes were also considered. Display was considered to be the size and color of the leaves. FALL RESULTS None of the 98 pansy cultivars were spectacular, although several performed respectably. 'Jewel Light Blue' performed better than other pansy cultivars tested. Yellow cultivars in TABLE 1. FIVE HIGHEST- AND general per- LOWEST RATED PANSY CULTIVARS formed better Cultivar (seed source)' Rating 2 than most other Five highest-rated cultivars pansy colors; Jewel Light Blue (T) ...................... 4.6 orange culti- Rally Orange (P)......................... .... 4.4 vars were sec- Fama See Me (B) ........................... 4.2 Accord Clear Yellow (G) ...........4.0 ond most Jewel Yellow (T) ............................ 3.9 showy. Table 1 Five lowest-rated cultivars illustrates the Roc White (S&G) ............................ 1.9 five highest- Fama Love Me (B) ...................... 1.8 Rally White (P)... ........... 1.8 rated cultivars Regal White with Rose Bl. (S) ...... 1.6 at the peak Accord Blue Blotch (G).............. 1.4 level compared 'Seed sources: Benary (B), Clause (C), to the lowest- Goldsmith (G), Pan American (P), American Takii (T), Sakata (S), and Sluis rated entries, and Groot (S&G). 'Fama See Me' 2 Scale: 0 = dead plant; 1 = small display of foliage with no flowers present; 2 = an d ' Acc or d adequate amount of foliage with no flow- Yellow' were ers or few buds showing; 3 = adequate the two top-to large amount of foliage and a rela- the two top- tively small floraldisplay; 4 = sufficient p e r f o r m i n g foliage and floral display to be attractive yellow culti- in the landscape; and 5 = superior floral display and sufficient foliage display. vars (Table 2). Ratings were made in whole number Many of the units. 4 ALABAMA AGRICULTURAL EXPERIMENT STATION white cultivars had lower ratings than the other col- ors. Of 21 yellow cultivars, 10 were among the 25 highest rated cultivars. No white cultivars were among the top 25. Conversely, 10 of the 13 white cultivars observed were among the 25 lowest rated entries. All of the ornamental kale entries performed gen- erally well. 'Red Chidori' was particularly notable. 'White Kamome' was well established by Jan. 17. Other cultivars made a respectable showing with regard to peak rating on March 21. Within each variety, plants were strikingly uniform in size and color. As of the termination of the test, none of the kale cultivars had bolted. 'Princess White,' 'Pink,' and 'Purple' were the ear- liest of the dianthus cultivars to show significant de- velopment. Foliage was fairly uniform and healthy in appearance. These cultivars exhibited good develop- ment of foliage and floral display particularly by late March. While slower to develop in midwinter, 'Prin- 1995 ORNAMENTALS RESEARCH REPORT 5 cess Crimson,' 'Telstar Mixture,' and 'First Love' came on strong in late February and early March to yield an adequate to attractive foliar and floral display. SUMMER RESULTS The few cultivars that received a 4 rating or bet- ter in full sun deserve consideration for use in Ala- bama gardens (Table 3). Salvia coccinea 'Lady in Red' was the top ranked of these cultivars, earning an aver- age rating of 4.5. Other top performers included Gomphrena 'Rainbow Orange,' Melampodium 'Medal- lion,' Verbena speciosa 'Imagination,' and Zinnea linearis 'Classic.' Overall, vincas also did well, espe- cially 'Rose Cooler' and 'Pretty in Rose.' Although none of the 78 petunia cultivars per- formed as well as these top-rated plants, several did earn respectable ratings. 'Primetime Pink' and 'Purple Wave' were the two best petunias in the trial. Others in the Primetime series also performed well, includ- ing the best salmon cultivar, 'Primetime Salmon Morn'; best lavender, 'Primetime Lavender'; and best mix, 'Primetime Mix.' 'Ultra Scarlet' tied 'Primetime Bur- gundy' for the best red. 'Madness Rose' was the best of the rose cultivars, while 'Ultra Blue Vein' was the best blue. None of the white petunias performed well; even the best, 'Butter Cream Carpet,' had mediocre foliage and poor floral development. Also, the All- America Selections Winner 'Celebrity Chiffon Morn' had only an average rating of 2.6 in this trial. Of the 30 marigold cultivars evaluated, the best African marigold was 'Inca Gold.' The best French marigold was 'Janie Flame.' All 63 impatiens cultivars performed well under 60% shade. Most received a season-long average rat- ing of 4 or higher. The Impulse series had more colors that performed well than any other series, including the top lavender impatiens, 'Impulse Lilac Blue.' The best white cultivar was 'Blitz 2000 White'; best mix, 'Blitz 2000 Formula Mix'; best orange, 'Tango'; best pink, 'Blitz 2000 Pink'; and best red, 'Impulse Car- mine.' 'Blitz 2000 Rose Star,' 'Accent Rose,' 'Impulse Rose,' and 'Tiara Rose' were all equally superior among rose-colored impatiens. All violet- and salmon-colored impatiens were among the highest rated plants in the test. 6 ALABAMA AGRICULTURAL EXPERIMENT STATION National Bedding Plant Production Increasing BRIDGET K. BEHE AND CATHERINE M. WALKER Nationally, the bedding plant market has been ex- panding over the last 20 years with increases more evi- dent in production units rather than prices. The objec- tive of this study was to quantify changes in produc- tion units and prices from 1993 to 1994 for both an- nual and perennial plants. Plant producers were asked to compare the 1993 and 1994 seasons in terms of numbers grown, prices, and total sales. A large majority reported increases in gross sales for 1994, and half of those who reported increases had growth of more than 6%. However, prices changed less than 1% for most producers over the last five years. Since sales increased more than prices, producers experienced an increase in units sold. METHODS Questionnaires were mailed to members of the Professional Plant Growers Association in 1993 and 1994. This organization had approximately 1,400 membersin 1993; 1,169 in 1994. Twenty-two percent of the members participated in the study each year. Members from 41 states and four Canadian prov- inces responded. The greatest number of responses came from Michigan (49), which accounted for 19% of the total. Respondents from several states in the Northeast accounted for 38% of the total: Michigan, Ohio, New York, and Pennsylvania. RESULTS Eighty percent of the members surveyed experi- enced an increase in gross sales, while 9% reported a decrease. Eleven percent reported that their gross sales had changed less than 1%. Thirty-one percent reported a 1-5% increase in gross sales, 24% reported a 6-10% increase, and 25% reported an increase of more than 10%. Four percent of members reported a decrease of 1-5% in gross sales, 3% CTION IN 1994 indicated a decrease of .Own Own Bought 6-10%, and 2% indi- es seedlings, plugs 3 plugs 3 cated a decrease of i35 40 925 more than 10%. 40 41 19 Small changes in 41 41 18 flat and pack prices : 19 36 45 34 41 25 were made from 1993 33 43 24 to 1994. Forty-four per- 40 41 19 S 33 42 25 cent of the respondents 42 25I 32 40 28 changed prices by less 25 42 33 than 1%. Forty-nine 15 27 58 14 26 60 percent of the respon- 22 41 37 dents raised prices, S 36 40. i24 47 37 16 while 7% of the respon- 34 36 30 dents lowered prices. 31 39 30 Forty-one percent of re- 42 41 17 35 40 25 spondents raised prices 35 41 24 1-5%, 6% raised prices 35 40 25 6 33 39 28 6-10%, and 2% raised 27 40 33 prices more than 10%. 48 41 1 Six percent of respon- i: 52 38 10 46 41 13 dents lowered prices 1- 50 39 11 5%, 1% lowered prices 41 38 21 32 25 43 6-10%, and 0.4% low- lant; I1= poor, 2=fair,3 =good, ered prices more than 10%. These price p as a 4. grew themselves or from plugs changes were very show the: percentage of growers similar to changes made ? " from 1992 to 1993. 1995 ORNAMENTALS RESEARCH REPORT 7 Solid increases were reported in the number of units (flats and packs) marketed in 1994, with 39% of the participants reporting increases of 6% or more. Seventy percent of the respondents sold more units, while only 10% sold fewer flats and packs. Twenty percent of the growers sold the same number of units as in 1993 (+/- 1%). A greater percentage of firms in- creased marketing more than 10% than were predicted in 1993. Thirty-two percent of respondents increased units sold 1-5% (30% projected increases in 1993); 23% increased units sold 6-10% (15% projected in- creases in 1993); and 16% increased units sold more than 10% (11% projected increases in 1993). Six per- cent of respondents decreased units sold 1-5%, 3% decreased units sold 6-10%, and 0.4% decreased units sold more than 10%. In order to determine some specifics in produc- tion and marketing of annuals, respondents were asked a series of questions pertaining to individual crops (Table 1). Nearly all respondents reported marketing several types of annuals. Plants marketed by the great- est percentage of respondents were impatiens, petu- nia, begonia, dusty miller, and marigold. Plants mar- keted by the fewest respondents were phlox, browallia, and seed geranium. Nearly half of all respondents re- ported growing each annual species listed. Members also were asked to rate sales trends for each of the annuals. The average rating was highest for impatiens. Other annuals rated as having good or better sales trends were alyssum, begonia, dianthus, geranium from cutting, New Guinea impatiens, lobe- lia, pansies, petunia, and tomato. Sales trends for pe- rennials as a whole were rated as slightly better than good. Four substantial changes over the 1993 season were noted in 1994. First, 30% of respondents rated dianthus sales as excellent in 1994, as compared to 25% in 1993. Second, only 63% rated impatiens sales as excellent in 1994, down from 71% in 1993. Third, pansy sales appeared to be improving; 55% of respon- dents rated their sales as excellent in 1994, compared to 45% in 1993. Fourth, 34% rated vinca sales excel- lent in 1994, compared to 24% in 1993. Some annual plants accounted for a large amount of the average respondent's crop. Impatiens and cut- ting geraniums were leaders, accounting for an aver- age 15% of the crop. Significant percentages of respondents used their own plugs or seedlings to produce alyssum, aster, dahlia, marigold, zinnia, cabbage, pepper, and tomato. However, more than 40% of respondents reported propagating begonia, perennials, New Guinea impa- tiens, marigold, pansy, verbena, cabbage, and peppers from purchased plants or plugs. Perennial plant sales were as strong as annual plant sales in 1994 with an estimated 5.3% growth in the numbers of units produced. Seventy-four percent of respondents reported an increase in 1994 perennial sales, while only 11% experienced a decrease. Six- teen percent had a change in sales of less than 1%. Twenty-three percent of respondents had an increase of 1-5%, 23% had an increase of 6-10%, and 28% had an increase of more than 10%. Four percent of respon- dents had a decrease of 1-5%, 3% had a decrease of 5- 10%, and 3% had a decrease of more than 10%. Pe- rennial plant sales continue to grow significantly as more participants reported increases of 10% or more. Perennial sales accounted for an average 15.3% of the total crop. They had a very good overall rating in terms of the future sales outlook. Twenty-three per- cent of the study's participants did not market peren- nial plants. On the average, a higher percentage of 1994's respondents marketed perennials. The mix of perennial species produced by com- mercial growers is relatively large (Table 2). This is reflected in the low percentage of sales accounted for by any one perennial type. Chrysanthemum accounted for the largest percentage of the average of any producer' s perennial crop, followed by hosta, hemero- callis, phlox, and dianthus. Fifty percent of the respondents rated hosta as hav- ing excellent sales in 1994. This was up from 37% in 1993. Significant improvement was also seen in sales of dianthus; 33% of respondents reported excellent sales in 1994, compared to 23% in 1993. Hemerocal- lis sales were slightly better in 1994, but sales of primula and salvia decreased to some extent. Increases were planned for individual types of perennials in 1995, although no one perennial was due to be in- creased more than 12%. 8 ALABAMA AGRICULTURAL EXPERIMENT STATION Consumer Preferences for Geranium Flower Color, Leaf Variegation, and Price BRIDGET K. BEHE AND ROBERT G. NELSON Previous research highlighted a strong preference for red flowers among many customers, but there is no information on preferences for leaf type. An AAES study was conducted to determine consumer prefer- ences for geranium flower color, leaf variegation, and price. There were differences in consumer preferences for these factors in geraniums. However, flower color was the most important factor, comprising nearly half of the purchase decision for all gender and age groups. As one might expect, consumers preferred lower prices. Leaf variegation had little effect on the pur- chase decision. METHODS Five flower colors were used: red, pink, white, coral, and lavender. Variegation is a band or stripe on the leaf; it can be dark or white. Three leaf patterns were used: plain green leaf (no zone), green leaf with white zone, and green leaf with dark zone. Prices var- ied from $1.39 to $2.79 in increments of 20 cents. Researchers developed composite photographs to rep- resent each of the 25 possible combinations of these factors. Consumers shopping at two Montgomery gar- den centers were asked to rate each photograph. The rating scale was from 1 (not likely to buy) to 10 (likely to buy). "Conjoint analysis" allowed simultaneous de- termination of the importance of each factor and se- lection of the most preferred product. Of the 204 respondents, 79% were female, and 21% were male. The mean age was 48 years, and the median household income was $50,000 to $54,999. Thirty percent had completed some high school, 48% had completed college, and 22% had completed ad- vanced degrees. RESULTS Conjoint analysis was used to determine the high- est- and lowest-rated plants (Table 1). 'Danielle,' a lav- ender geranium with green leaves surrounded by a white zone, priced at $1.39, was most preferred. 'Snow White,' a white flower with plain green leaves, priced at $2.39, was least preferred. Contrary to pre- vious studies, red geraniums were not most preferred. Conjoint analysis also revealed the relative im- portance of each factor when consumers were making purchase decisions (Table 2). For the sample as a whole, flower color was most important, followed by price. Leaf variegation was relatively unimportant in the purchase decision. For men, flower color and leaf variegation were more important in the purchase de- cision than for women. Retail price was more impor- tant to women. Consumers older than 60 used flower color and leaf variegation more than the group overall in making their decisions. Since flower color was found to be such a major factor in purchase decisions, plant breeders and mar- keters should focus more on developing and selling different colors of geraniums rather than different leaf variegation patterns. TABLE 1. THREE HIGHEST- AND LOWEST-RATED GERANIUMS Rating Flower' Leaf Price Highest-rated 6.562 .......... Lavender Var 3 $1.394 6.39................... Dark Red None $1.39 6.36................. Lavender None $1.59 Lowest-rated 4.66............... Pink None $2.39 4.27............... White None $2.79 4.21............... White None $2.39 'Varieties: lavender = Danielle; dark red = Flame; Pink = Mrs. Parker; and white = Show White. Other flower colors were coral and red. 2 Average rating on a scale from 1 (definitely would not buy this plant) to 10 (definitely would buy this plant). 3 Leaf variegation was none (none), green leaf with white zone (var), or green leaf with dark zone (zone). 4 Prices were: $1.39, $1.59, $1.79, $1.99, $2.39, or $2.79. 1995 ORNAMENTALS RESEARCH REPORT 9 INSECT, DISEASE, AND WEED CONTROL Crapemyrtle Cultivars Resistant to Powdery Mildew AUSTIN K. HAGAN, GARY J. KEEVER, CHARLES H. GILLIAM, AND J. DAVID WILLIAMS Powdery mildew, which is caused by Erysiphe REACTION OF CRAPEMYRTLE CULTIVARS lagerstroemiae, is a common and sometimes damag- TO POWDERY MILDEW ing disease of crapemyrtle. Although severe mildew infections have little visible impact on tree vigor, the Cultivar Disease rating off-color, distorted foliage on heavily diseased Gray's Red.......................................... ...................... 2.3 O rbin's A dkin .................................... .............................. 1.8 crapemyrtle detracts from this tree's ornamental value. Carolina Beauty .............................................. ... 1.7 Powdery mildew often is most noticeable on the "seed- PI6789220 White........................................................1.7 ling" or volunteer crapemyrtles, which are found in Byers Wonderful White ............................... 1.6 'Po tom ac ............ .... ..... ............ ......................... 1.5 the landscapes of many older Alabama homes. Zuni .............................................. 0.9 Establishment of mildew-resistant crapemyrtle Country Red ....................... ....................... 0.9 cultivars has been recommended for years as an alter- Hardy Lavender ....................... ..................... 0.6 Pecos .................................. .............. 0 .6 native to costly, time-consuming, and sometimes in- Seminole.............................................. ...................... 0.6 effective fungicide spray programs. In 1994, the se- Raspberry Sundae....................................................0.5 Y u m a ................................................................................. 0 .5 verity of powdery mildew was evaluated in a field William Toovey ............................. .......... 0.4 planting of crapemyrtle. Of the 45 crapemyrtle culti- Majestic Beauty ....................................................... 0.4 vars evaluated, the majority demonstrated good to Caddo .............................................. 0.3 excellent resistance to powdery mildew. Natchez .............................................. ....................... 0.3 excellent resistance to powdery mildew. Velma's Royal Delight............................. .................. 0.3 M ETHODS Glendora White ...................... ....................... 0.3 Pow hatan ............................................. 0.3 Bare-root crapemyrtle (Lagerstroemia spp.) was Regal Red ..................................... 0.3 planted March 3, 1993, into a Marvyn loamy sand soil Wichita................. ................................ 0.3 on 20-foot centers in rows spaced 25 feet apart. Plant- Centennial Spirit....................... ...................... 0.2 ing 20oles nteresdugowssepacf25eeAr l Basham's Party Pink ............................................... 0.2 ing holes were dug to a depth of 24 inches. A trickle Cherokee..............................................0.1 irrigation system was installed shortly after tree es- Hopi..............................................0.1 tablishm ent. Trees were grow n in full sun and irri- Near East .......................................................................... 0.1 gated as needed. Each tree was topdressed with 3.2 Choctaw ............................................. 0.0 ounces of fertilizer (13-13-13) on M ay 26 and June Sioux.................. ................................................. ...........0.0 24, 1994. W eeds around the base of each tree were Apalachee ......................................................................... 0.0 T u scarora .......................................................................... 0 .0 controlled with a weed trimmer and applications of Acoma ...................... ....................... 0.0 Roundup. Alleys between rows were periodically Muskogee ........................................... 0.0 M iam i ................................................................................ 0.0 mowed. Disease severity was rated on Aug. 4, 1994. Peppermint Lace ............................. 0.0 RESULTS Comanche ................................ 0.0 Fantasy ............................................. 0.0 The highest disease ratings were noted on the cul- Osage............... .......................... 0.0 tivar Gray's Red. Extensive powdery mildew devel- Biloxi ............................................ 0.0 opment also was observed on the cultivars Orbin' s Sarah's Favorite ................... ........... 0.0 Adkin, Carolina Beauty, PI6789220 White, Byers Pi6789713 ............... ................ 0.0 Wonderful White, and Potomac. Light colonization Tuskegee.................................0.0 and distortion of the leaves was seen on an additional Tonto........ ............................... 0.0 22 cultivars. However, 17 cultivars were entirely free 1Scale of 0-4, with 0 = no disease; 1 = 1-25% of the leaves damaged or extensively colonized by the powdery mildew fun- of powdery mildew symptoms. gus: 2 = 25-50%: 3 = 50-75%: and 4 = 75-100%. Application of Pesticides and Pesticide Combinations for Control of Liriope Scale on Container-Grown Liriope sects, allio11)i the il~ te e~d pestN s of Coliii I-< ejalix Lroml liioe ,A I iiodea, a111( related -7 eel lnts iioil ut thei laThe eale velOF et' M iIICdti)I ut~ lirioptt JUIle. The sc~tneale IN c 1 ittohile: otnee settled onl the luiliac. it reillainNi attached 'or. thle remlainlder oft, it t.le. Seale itnects olteni Lo nililu0IL unt11il I)LlknttiOlN Ia\C e reahed high le ekVIS at w hieh time the eiorotie spottinu produILcedI 11x teed- ilInCC coneNC e den1t. A10th1onoh1 tir-iope pLlanN III oult door planting's niax1 become Ilestedconllaine i o'" n plats are at _,reatcslt risk. When in~tetionN heeOmei (ONI Ito 01~ IAioV(Iuuu No AL tOtN I nlntilcl \o:N . lio iil ii i Oillienc 15(; _ . 0.1 gpot 37 I 7.0 0.0 Ollicinc 15(C; ... .... .0 2/10t 1.25 0.75 01.001 ( ccn e IS( _b ...... 0.30 I' o 0 0.00) 0.00I Mciii 5 Gl 01........2g 1 00 2 pil . 0.50 0.00l 0.0 I elioninI ___ i i....i.. l - i 9.75 s)) (uan i (i) i ,,ciftlecel il he wcil slililic: ( ' 'c 2F Midi SLin1 1)1\ OF ip li~ cil 0 il tio1 Ic iLi ic1 Rkitle ot icl a cm iilick ntl ii',Cd ill C (1 cad Ir i cni. Aoian nuiihei of Iii inn_ llCI[t' peif cii blade~s 1)T = J iti Iicalttilt lien \ onl ColltainIet iieilo- pltsN r apid decline ill plantl hecalth and dleath miaX result. Ini 1 199 3. sNevcX 11 en peti ce XX Icswcre c a iIt. natecd totr c 0 11 trol oft Iii lpe Neale Wi 'oniiiNi (l ri( 6 ) onl coilll et A p ) o it a. T hu i P I \\ Neate inlestect hl ptits' itl trade oatlk cotlilner wXere NC- leeted t'ot ti eatilmentl Pesticide testN \\cl i lii tiated Aug. 30. 1993 1-NIiCh both t'oliar Nfl 2\N and( Ci aliu at matetril. LotCC 10 Np! axN XX te hand-(1hetd eullpreNsieil 2)11 NC~~e ate \Xi, [AIket 10_01.oroutNht\ L'I 2ltt Itaflt NLIIta eN. \t ci ire2)tilet Lill Npt ax c plat \X etc 2)Ilo\X etol ril N r sXe pr inkle tei I I 71-itu 2. ( taracterislic tei rin "pot ing (I Pt Xd ).N ki-AIMI k k(AM I LH R ki, EXPERIVENA SFk Hill, 1995 ORN \\INITAS HI SI \RC RIETO RTII Ai 1 igu re 3. Scale co~ er ofI adolt teiiiale insect on leat. rect ly Onl the Soil surfac e. Plants xxerc placed uniII an1 mxci-hid spr inkler sy steim xx ithinl aI SlhidelILSe at tlhe AubinLII LJInixei-sitx Pesticide Research I acilitx Plants xxere then Watered or01 one hour. After thc MAl \\lxxt ti i ug plants were xxatererd as neerded. RIES I JIFS Sex erall pesticides c altLiaer ll this test pi ox irled excellent contirol, ol cil inc mxers nexx materials to be Used to combat 1 scaleC insect infestations. After 56 days. 11114 rontrol ot lir-iope scale xxas obtainler from the f ol lowxing pesticides: (rthene I15G at rates areater thani 11.015 LIFm1 0t itixe in'1Iielit peti pot. StiiispiayV 6E. Cy eon 2E, and Merit 2.51/ G (see table). Of the sexven pesticides tested in I1993. only p~lanlts treated wxith Ortheine I 5G at the 0.05 cram per pot i ate had it% ing, insects after 56 days. Phx totox ieii\ wxas nlot ohsei% x d in any of the treatments. Eairly rccoalnitionl of inlesta1 tion1S coupled with pesticide application may help in the maniacemlent of, iriope scale. Figure 4. Liriotpe scale infestations are often oxerlooked b~ecause of the insects' habit ot'clustering at the bases of' the leat'sheaths and Mlade axils. Managing Boxwood Leafminer in Containerized Boxwood The boxxxood Icafl minei .Mollr/ iropa /pux ho xi U~abon Ibene ). is consideired by many to be the most seriAous insct pest of boxxxood. and is banlId fiom1 the At lint ic to the Pai ic wherexver boxwooud ,roxxs. Ail AA LS Sstudy identifiedr sexveral insecticide treatnments to cointrol the lcaflminier. FlexC enculti x arS ol )it-it ax empipL n, as wxelI as Bums x icro ph x// and B3. harlandi, may become heavily infested wxith boxxxood Ical minci. Dxx arf En- Olish boxwxood, . itlhi muanIw is rarely infested, and the x aiictics /)eldula and (irgieite() i'(neg'tal appear to be immune to attack. InI Alabaima. boxxxood leatminci has a single (ecui erationl each y ear. passing the Wxinter as partIV ginxx nl larv ae in the leaxvcs. InI early spring (March Api i). the larx aC dcx elop ra pidly, puIpate xwithi n the mine inl the cat', and emerge as small orange flies. The aIdult flies nate and bei-in IaN inc cccx, wxithin txxo to thIi-C houi -s after emergence. Lggs hatch inl abhout 19 days. and the larxvae develop slowly Utit iC all wxhen they begini to increase considerably in sizc. The effect ot an occasional boxxx ood lea minci in F igure 1. Boxxx mod Ieat niner damiage. aI leaf is no0t Si "IitfiCailt but ill heax x infestations fixe or m 1ore I a rx ac miay dcx elop inl a single ICAl . Inl this situation, the larx all mining activxity sexverel y xxeakens the plant, making it m111- esusceptible to attack by dis- ease and xxinter kill inl colder areas. UAAM AGCUL TURAL I'.\'I RME'N'I STATlION ME TH-OD)S Six pest icidle treatments wxere e\x al uated 'or contr ol ot' boxwood lcafmrincr intestine OIuuduOi . e otutat nCrer1IOxxiI boxwxood. Test a tci ai werei applied Aug. 30~. 1993, lo two-0 t'oot-tall boxxxoods orowxino inl three-Lallon contai ners. All plants w.xere heav ily iml exted with0 boxxxood leat inler larx ac. Pretreatment counFts Of' teil leaxves ax eraoed 9.7 lat xac pei Ical 1. GranuIlar1 l'ormuIlionlS Wxere SCattet ed oxver the soil su-rta c inl thle container, and Cy-on wxas appl icd as a t'oliil Spray Using at hand-held comlpressed aii xpt ax ci. Ciaie wxax taken to cix~ ci undetleS id 0ea' ICIeS With thle Cygonl spray. Atker treatment application, fo - liai xpiaycd plaints we re allowed to dry, and all plants we rc randomized inl a block Under anl ox rcihad sprinkler sy stem. Plants we re then iriIMI 1at1d orI one hour. Alter the initia irri-a- tion. plantx wcire wateired axs needed. Elf icacy of' materials was determ ined by dissect ins 40 leax cx IL-rout echW treattuent111 and coun[tingL thle nriberI~1 o1' lix inc larx aIC. RI1{S U LTS A S1111MmrY Of' results ix preCsented illi the table. Excellent reduIction ol' the lcal'mmnct poplaktionl xxas obtained at the 56 day posti treaitmlent period wxith the highei ratex of' ()rthene 1 5G, Merit 2.51/ CG. and ('ygon x No) phytotoxictty xxax obxerxved wxith aty treal, ment. The suIccess ot thle granuI)lalr pesticide in cointirolling boxwood lea'm irncr inl containc FtJ 'igure 2. Adult b)Xoxu t Ical'ininer. plants pro ides another approach ti) manag- ing1- this peCst inl thle n c rser\V or IWWnSCaIpe. C'u\ I ROI, OF ilOXw OO Lki Mi INEiR A? O\ (CON I \ixi RI/i l) Box%%ooii 7 DA I ' 8 DA\ 1 *) DA I ()iilicielc ....... .05 6,.50 65.501 41.00 ()itheie 15 G ........ 10L-, x 8.2 44.80 34.7 Ortii e 15 G ......... .2 53.50) 3.3() 5.0)0 Oriflene I5 G 3) ........ .; 45.0)0 10.50 Metiit 2. 5 %; ( ..........04' L 5 .25 10 ) N o 'tn 21 .......... 0.5 lb1 49,00 8.30 1 (urn ol . . ............ -- 70.5 04.80 74.50) I rciuuniis sxee apliedt AI,(. 30.,93'ruiilu ~e kx c ',iCuteiet uui'Oil iii1 Utaut. ill puut, xx bile Vxii xx'O i is pplied. ,I' a toiar ry 'Rate ilie ,iloiiuili 01 .iutix inieI-duit ap1pIedC ii eatd 8)O oi t the guitilI1M iIttet I Ori C 3guiui late is the 11i10u]nt Ofl :ieC uiigiedlielt pei 1001 gallonsi ot xxaiei. Thi' ks the mtian ritthei iii lix in' larx ac pet 10) leaes cx lie itcil atisaled. Sei( 6, Sept. 27. and Ot. . 1993, '[)At I dlav ait letic altini. F~igure 3. Iloxx~oiod Icatininer Iarxae. 1995 ORNAMENTALS RESEARCH REPORT 13 Fireblight-Resistant Crabapple Cultivars AUSTIN K. HAGAN, KENNETH M. TILT , J. DAVID WILLIAMS, AND JAMES R. AKRIDGE Diseases have greatly limited the use of flowering crabapple in resi- dential and commercial landscapes across the South. In Alabama, fireblight, cedar-apple rust, and apple scab are the most prevalent diseases on flowering crabapple. Use of dis- ease-resistant cultivars, the preferred method of controlling these diseases, greatly simplifies tree maintenance by virtually eliminating costly and time- consuming pesticide applications. As part of the National Crabapple Evaluation Program, an AAES field trial was initiated in 1992 to assess the adaptability of 60 crabapple cul- tivars to the Deep South. A number of crabapple cultivars demonstrated moderate to excellent resistance to fireblight. METHODS Bare-root crabapples (Malus spp.) were planted in May 1992 on 18-foot centers in a Benndale (A) fine sandy loam at the Brewton Experi- ment Field. Before planting, soil fer- tility and pH were adjusted accord- ing to soil test recommendations. Approximately three pounds fertilizer (5-10-15) were evenly distributed annually around the base of each tree. The trees were not irrigated. Weeds were controlled with directed appli- cations of recommended rates of a tank-mix of Gallery + Surflan or Roundup herbicide. Visual ratings of disease ratings were made on May 28, 1993, and May 24, 1994. RESULTS In 1993 and 1994, fireblight out- breaks were noted in the flowering crabapples. Each year, extensive blos- som blight, dieback of numerous shoots, and canker development on the limbs was observed on the most heavily damaged cultivars. Only a single crabapple selection, M. baccata Jackii, was free both years of fireblight symptoms. Over that same time period, very minor and un- obtrusive fireblight damage was noted on the cultivars Coral Burst, Pink Princess, Spring Snow Dwarf, Jewelberry, Robinson Dwarf, Adams Dwarf, Radiant, Velvet Pillars, Adams, Pink Spires, and Dolgo. An additional 17 crabapple cultivars suf- fered moderate and unsightly damage in 1993, but disease severity in 1994 was lighter. Extensive fireblight-in- cited shoot and limb dieback consis- tently occurred on the cultivars Mary Potter, Sentinel, Siani Fire, Snowdrift Dwarf, Silver Moon, Snowdrift, Golden Raindrops, Klehm's Imperial Bechtel, Brandywine, and Hopa. In 1994, observations were made on the severity of other diseases. Symptoms of apple scab appeared on the leaves of five crabapple cultivars. Significant disease development oc- curred only on the cultivars Radiant and Eleya. The occurrence of cedar rust disease was limited to light fruit infections on a few scattered trees. The leaf spot phase of cedar apple rust was not observed, nor was powdery mildew. Thirteen cultivars of flowering crabapple with good fireblight resis- tance have been identified. Of these fireblight-resistant cultivars, only Ra- diant was damaged by apple scab, a disease most likely to occur on trees in the northern third of Alabama. With the exception of Radiant, the fireblight-resistant cultivars would be the best choices for use in Alabama landscapes. Shoot blight and limb die- back was so extensive on 17 crabapple cultivars that they cannot be recommended for use in Alabama landscapes. 1995 ORNAMENTALS RESEARCH REPORT 13 Evaluation of Selected Herbicides on Field-Grown Woody Plants JESSE A. REEDER, CHARLES H. GILLIAM, KEVIN R. KEEL, GLENN R. WEHTJE, DAvmID B. SOUTH, PATRICK PACE, AND GARY J. KEEVER A greater diversity of difficult-to-control broad- leaf weeds, along with crop sensitivity to herbicides, make weed control more of a problem in field-grown nursery crops than in container production. For many years, the most common and widely used broadleaf- active herbicides for field-grown plants were Goal (oxyfluorfen) and Princep (simazine), both of which can injure some landscape species. Recently, Predict (norflurazon) and Pendulum (pendimethalin) were registered for use in field-grown nursery crops. Previously, Predict use was limited to cotton, cranberries, and various fruit and nut trees. Pendimethalin has been available for use in container nursery crops for several years as Southern Weedgrass Control, a granular formulation. However, Pendulum is a water dispersible granule. An AAES test showed that Pendulum is harmless to field-grown woody plants and provides adequate weed control in field-grown nursery crops. Predict provided almost total weed control but caused temporary foliar damage. One of the TABLI primary herbicide treatments used in field production in the Southeast -- Surflan ap- Treatme plied in combination with Princep -- was among the least effective at controlling sicklepod in this study. METHODS Predict. Predict+ Liners of 'Acoma' crapemyrtle, 'Chesa- Predict+ peake' viburnum, live oak, and 'Mary Nell' Predict+ Surflan. holly were planted on April 12, 1991. Surflan4 Granular fertilizer, 13N-5P-11K (13-13- Surflan4 13), was applied preplant at the rate of 52 Pendulw pounds of nitrogen per acre, and annually Pendului thereafter at 120 pounds per acre. Irrigation PendulUi Pendului was provided as needed with Chapin twin- Weeded wall VI irrigation hoses containing holes Unweed every foot. Plots were 12x16 feet with plants 'Predict, spaced 3x3.6 feet. applied treatmer One week after planting, herbicides The wee were applied with a CO 2 backpack sprayer 2 Injury r equipped with a 8004 flat fan nozzle at 28 3 Growth pounds per square inch, in a spray volume inch equ of 20 gallons per acre. Pendulum 60 WDG, 4 Applica 23, 1992 Predict 80 DF, and Surflan 4 AS were ap- shows : plied alone or in combination with either Gallery, Goal, or Princep. Herbicides were applied on April 17 and July 22, 1991, and March 17 and June 23, 1992. Weeded and nonweeded control plots were maintained. The test area was overseeded with sicklepod and goosegrass. The test area contained an erratic population of yellow nutsedge. Consequently, the entire area was treated with Pennant (metolachlor) 7.8E before application of the other treatments to sup- press yellow nutsedge as a confounding variable. RESULTS Crapemyrtle. Injury following the first applica- tion in 1991 was caused primarily by Goal. Goal in combination with other herbicides produced 92% av- erage injury at 30 days after treatment (DAT) and 86% at 60 DAT (Table 1). Injury was restricted to new growth. Crapemytrle was not obviously injured by Goal in the second application. There was no crapemyrtle injury from the first application of Pen- 14 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 15 dulum, Predict, or Surflan. After the first application, only Predict or Predict combinations caused crapemyrtle injury. The injury, characterized by bleaching of the older foliage, dissipated by 90 DAT. There was no injury in 1992 (data not shown). By October 1992, all herbicide-treated plants were simi- lar in size to the hand-weeded plants. Viburnum. Predict, applied alone and in combi- nation treatments, caused bleaching of 'Chesapeake' foliage 30 DAT in 1991 (data not shown). Injury symp- toms were similar to those observed on crapemyrtle, and they dissipated by 90 DAT. There was no observed bleaching from 1992 applications of Predict. Gener- ally, the Predict-induced injury did not reduce growth indices, reflecting the temporary nature of this injury. Live Oak. Maximum herbicide injury occurred at 30 DAT in 1991 with all herbicide treatments (data not shown). However, it was difficult to distinguish between herbicide injury and transplant shock after field planting. Nonweeded plants experienced 29% injury at 30 DAT, providing evidence of post-trans- plant shock. By 90 DAT, plants had generally grown past injury symptoms or transplant shock. With the July 1991 application, plant injury was generally great- est when Predict or Predict combinations were applied. Predict symptoms were similar to those observed on crapemyrtle and viburnum. Growth indices of live oak in all herbicides treatments were similar to the hand- weeded plants both years. Mary Nell holly. None of the herbicide treatments resulted in visible plant injury in excess of 10% (data not shown). Injury was restricted to Predict. Growth indices were not influenced by any herbicide treat- ment. Weed Control. Control of sicklepod, a major weed pest in field-grown nursery crops in the Southeast, was consistently enhanced when Predict was applied (Table 2). In 1992, Predict treatments provided almost total sicklepod control. Pendulum and Surflan provided about the same level of weed control after the first two applications. Thereafter, Pendulum generally pro- vided greater sicklepod control than Surflan. The rela- tively poor performance of Surflan + Princep may ex- plain why sicklepod is often a troublesome weed. In summary, Pendulum is safe on field-grown woody plants and provides weed control similar to existing programs. Predict provided the best weed control, but it caused foliar injury; however, plants generally grew past injury symptoms within 60 DAT. Current registration recommends delaying Predict ap- plication until one full growing season after planting. Data from the AAES study support this recommenda- tion; most Predict-caused injury occurred with the first application after planting. 1995 ORNAMENTALS RESEARCH REPORT 15 Adsorption, Desorption, and Leaching of Oryzalin in Container Media and Soil GLENN R. WEHTJE, CHARLES H. GILLIAM, AND BEN F. HAJEK Irrigation runoff from landscape plant production areas and established landscapes has been suggested as a source of pesticide contamination for local water supplies or surrounding bodies of water. Studies have been conducted on the leachability of some herbicides, but there was no similar research on oryzalin (Surflan). A recent AAES study evaluated the adsorption, desorption, and mobility of oryzalin in soil and soil- less container media. Data indicated that oryzalin movement in media is limited and would not likely be displaced out of the container via irrigation runoff. METHODS Oryzalin sorption was evaluated in soil (Marvyn sandy loam, Typic Kanhapaludults) and three media: rice hulls:peat:pinebark:wood shavings (1:1:1:2) (R- P-PB-W); pine bark:sand (7:1) (PB-S); pine bark:peat (3:1) (PB-P). Application rates ranged from 0.01-100 parts per million (ppm). Desorption was measured in the soil and R-P-PB-W, at the treatment rate of 10 ppm oryzalin, by a series of water extractions. Additional water was added to replace that extracted from the soil and media. Equilibration time between each extrac- tion was 24 hours. Oryzalin mobility was evaluated in each medium and the soil by use of a column leaching technique. RESULTS Oryzalin adsorption (attachment to media par- ticles) by the three media ranged from 93% to 95%, regardless of oryzalin concentration (Table 1). At con- centrations between 0.01 and 10 ppm, adsorption by the soil and by all media was statistically the same. At 100 ppm, adsorption by R-P-PB-W and PB-S was greater than by soil. In contrast to the media, the pro- portion of oryzalin adsorbed by soil was inversely re- lated to the concentration: 96% at 0.01 ppm and 90% at 100 ppm. The amount of oryzalin removed from R-P-PB- W with each of five consecutive extractions was 7.4%, 4.2%, 2.6%, 2.7%, and 2.8%, resulting in 19.7% cu- mulative extraction. The amount recovered decreased by 43% between the first and second extractions, and by 38% between the second and third. Analogous val- ues with the soil were 8.9%, 5.6%, 4.2%, 4%, and 3%, totaling 25.7%; the decrease was substantial (37%) only between the first and second extractions. Oryzalin adsorptivity by the soil and R-P-PB-W were identical based upon a simple one-time equilibration and ex- traction experiment. The medium had a slightly greater resistance to desorption over repeated cycles of rewetting, equilibration, and extraction than the soil. The leachability of oryzalin in R-P-PB-W and PB- S was identical (Table 2). Nearly all the applied oryzalin was retained within 1.6 inches of the soil sur- face, with a minimum of 91% held in the top .75 inch. Oryzalin was least mobile in PB-P, with 99% being retained in the top .75 inch. With the soil, less was retained in the top .75 inch and correspondingly more was retained between 1.2 and 1.6 inches. For both media and soil, oryzalin adsorption and resistance to leaching was high, and adsorption was somewhat reversible. Weed control activity in nurs- ery and landscape situations probably depends on this desorption. Each rewetting of the medium through ei- ther irrigation or rainfall results in a portion of the applied oryzalin reentering the soil solution, where it can be adsorbed by germinating weed seeds. 16 ALABAMA AGRICULTURAL EXPERIMENT STATION 199); 0)I0, \\iINI I US RI SI k( I RI PO( 1 17 Evaluation of Selected Fungicides for Control of Southern Blight on Aucuba Iris N .0 15 \n Sn \ Ni % I \ K. I I v; x both rnl the landscape and nrsr.lIII an \AAL1S cx aln atiOn l seected CI irr11(iciides, IProstar 50W, ASCi6682 S. and a1 hi r0te o IiCIr 3.6F pros ed to be el lectix itl court Olrirl the driSease onl anenbahz ini container pio The dlisease. caIrSed by the InLFLII nncrs ot rlfii, is Characterrized by pr-otLIC se xx hi te niy eel growsth onl the lowser stem ol' irilected planits. Thi- thle tr1'CieCd P-lait. S1iih1,o1 on to ronIId l I [rHIre kriosrIF a,, ,clcrot ire utei pie clii 0l imiil iii11 thle disea e,, Fu rilrruoo ItLL1xxi H10 SIMJ IM r sPin or I\r OF 1 99; I 994 \S '0 82 0 1 .. t ........ I n li 3 .7 ............... tc i i 7 ' ...rn .. .. .. .. .. .. . I ni ri,incul (O ................ I 11 ln SO n i F ................t 3, H. o/. 8 It. / I Th lb. I lb 0B 63. 63.1 100 METHODS 1) Im 11a o /(i/)/la tierl N 55crc potted III a 3: pi ne bark-peat 1i1oss nIictlinii inl rd (I allor101 con~tainerIS. lie HIiiidrnn k55l as ICCC arirde ith 14 p-ounld's Ol' ()smIloeote 17-7- 12, six P)oLInds o1' dolo1iiC limeIstone. tsso Pi)OllC rsOf' rOypslriiiI, andI 1.5 pounds of' micrornax per cubic Yard. Plants xx ci e gio\ (155i in aii openl. plas"tic cox- ci~ eul tCrerihouSC arid v'. tet d dalikIN. FIFneiC ideCS xx er app)Ilied as1 ai spitN /drerCichI usi rig I C pi e',IIsSnrIi/.ed spray er. Appro(ximiately lIV xc101 aloris totalliqid ol- IneI perl 100( stIIare f'eet wet e applied to each treat- mienit. All treatmencrts. except or01 the nrliinocnlated con- tItiL. \Vx- cr1cLIMC inclteW.ith . oI/xiiin~lested xxheat Seed 24 lionI- s1(alte lur11irCide app)Ilica1tion1s. Plant death wxas Cleterriirrrcnd 601 day-s alter iniocurlation. Ari initial ex- per i riiri pr1os ided aI gener1Ca l I uriicide screerirne. A seCOndC stLndy I OCursedI onl deteriin rg the (iptirl]uILII rales o, Chemic rals, that pro\s ccl elITecle inl screen inc". soitirrn bilighit is chrar-actur iid I) , projus %%r hit grm if) oil tile loNer stems ol, ildected lantsi. RESUT) iS III the InnejerdeICI screenIing. planits treated ss ith AS('66825 Ilnainamn) or lProstar 50W~ exhibited no disease symnptoms 60) day s al'ter, teatilent ill either 'ear. Terraiclor 75W, Fo1iCeni 3.01 and I erraguard 50W pro\ ided conriol in 1 99 3 ho\sxe cilli 1994, all thll-c t'ailed to pt oxide satisl'actory CvI-1 eotrL(InraILa pi-m ided no control ini either N ear (Table1) ReStiIts Ol' the I ate-I CV~d MxlIrroirS xxereC Si IIr ilr inl both Nears and idricated that, at 001 dav s alter treat- mencil both Prostar 50W arnd AS('0682 S protected atrCiba i'oni S. rn/f xii at all r ates tested. FolreUr 3.61, xx as not ectc at loxx ci r ates but p)i x CCl excel- lentl control at the hiehdest rate tcested (Tale 2). Ixjuii 2.lrrr I ( O Air'rr k Ins- R xrIiso(Ii I Ft N'si ir os () r xI v Ix r 1 r) t ri xx IF NN irI S. Rolii s// I '1ciii It Ic/191 IiA Pi. dcklplr I Q93 1994 Fl i CL 3.. .I ........t Pn nn~rar $5% ........ \%(1n6825 .......... irloultid Contrl ... ['1 1 U t itrd ( uniol 4 1I. o/. 8 1. o/.. 10- It.o/ O.n 1h. 1I .0h 20 IIlb. 8 II. o/. t10 It i/. 32 It. o/. 87.8 011 Is \ BANI k GRI~t IA I LIIP.IIIISII Evaluating Phytotoxicity of Insecticidal Oil Sprays on Selected Container-Grown Plants CokRxTi's I'. Hissiiis,, NIFiI)IoiKi NN. Fsiaii I ncreasedl -overni invint rec-tlation., cOHl cern foi woirkplace____ for econhoimically, el' lectix e methods 01 l pest mlariagel-ient aic coipci 11ia orniamenil tat plant tIroxx-st seek noveli and mr beniLn nliethod I petro1leum1 oil has beeni nISCC inl n[Seet COnti o p ]odiieecrs ti aditionallx have ax'i~ oiLel" o it dueI 101 its reCpntation l~ for daiiiaeill n roxxln pltants R ecenlt tee ino F)I Iigure 1. I' ox~erm od NurserN 1) ogy has resultedC inl niaiT rohrne i uth I refinied. *SLutrnmer oil. D lespite the f act that this oil can be safely sprayed on most actixvely girowing cirops. m1anly oi itamenCtal pi odcLIer-s are still apprehensivxe about its LisC. Hoxx e i an AAI:S study eon liimed the relati xe salety of insecti- cidal oil nise oxvei a wxide rangec of plant species. It is efftect ive, sate for- thle en ~iron menCt anld h~lman health, and compatible wxit h othei pest manage mnict tactics. Insecticidal oil has a wxide rane-e of actix itv aoainst C0111i1101 01 n1alinental pests. 'web as aphids. SCAC les lea- Ili sNis S USED IN Oil PHi'i'\ iIwr TRI i (eniteiiiil ipli it iOlpemtt\ i tscati let t ae,iie C. tolie,ter iiil 'h [ipl[il ttilt tJaaiee~ tlixxuid titiLe Sonlomon A/aleci Rene Mliiclle' ,',ilea Spiraca ~ Clim itPrt'enm' Barhcrr. Chinree Pii'.t lii, ttLn I iilp Rou' Ciit ivHiFll' Pink Gmurrpo A/AiLt ~ ( iiipaitai t1oll 1tlix ti iti)\ 115 b.ei ed 9/9/94. tI'hltotoxicity ubset 'ecc 9/9/94 iant 9/2 3/94. ersoiliel spray ing plan~ts ini oil phi~totoxhuti ii rial. ly bug(s, immall~turIe xx i tellies, and all stages ot mites. Target pests haxve shown i little or no resistance to in- secticidal oil. Short reSidnal actixvity makes the oil sprays less hai mflI to beneficial insects. Loxx mai- malian toxicity andI iesidLues that are readlily mietabo- li.'ed by bacter ia make insecticidlal oil x er\ sale lot huImns andI the enxviron ment. These positixve attn bhiteS make insect ic idal oil a good candidate for- use inl IPM proorams. as wxell as inl labor-i ntensixc e it~iatiOnIS SLICh ats those 1 o1l nd at Most nur11ser-ies. N I EFH 01)S Twxenty di fferent ornamental plants xxI- eie tset Ill a s~immer 1994 demonstratioin tiial at P loxxerxxood N Lrsery in I L)xley, AlIa., to Ldetermline thle phytotox city of insecticide oil ( see table). These plants wxere choseni becaLISe thle)' aie pieC terredl hosts of the ty pes oft in sects that oil S~pray s are knowx to control. Twxo oil prodietsS n sL1pr-aV Ultira Fine Spiray Oil and Target Oil -- were testedl ait the i ate of onle gallonl ot oil per 11)0 gallons ot spray SOlLitionl. Six treCatmenClts xwere testedl: a morn- ing spray of each oil prol-Oiel. anl atternoon1 spl-ay 1995 ORN AII'N IXI RI' F' R( II RI' ORT ol, each, and txxo xwater controls. Mornling, is the reec oiumenC~ded timle to spi aly. bCcause Liatei n(on is Wxhen phy totoxiCity i5 Most likely to OCCLII. All plant sur- I'CC a Ws ere spra yedI unild cin1f11I Spril: xing Cxa oll duLctedI by Fl owet xxood N UI Sery ( FiniI- I I). Plants wxere Spa_ yed u[si no a hand-held (;reen (;ardc J D9-C spray gunll at appr oximately 200) psi at the bypass xvalve. Plants wxer e spr ay ed onl Ang. 9 and Sept. 6. The teinlpeia tLiieC xxas 78"F and the reclatixe hnmidity 831'% onl the morni, to otAL1n. 8 87+F and 6714 onl the atfter- noon of Ano1. 8; 84"F and 8014 on the mornino ol'Sept. 6; and 9 1 'F and 7 1 / onl the at'ternoon ot' Sept. 6. Weat her on hot h dates Wats pdrtly eIl oId. Plants Wxere ex lhltd I'1 or iS Oot' phl toto\ iCitV three and sex ell day s af'ter the tirst spray and three and 17 dax s after the second spray. R ES. I LS No phytotoxicity wxas observ ed fol lowsing the I'irst spray . Onl Sept. 9, the F irst obserx ation date alfter the second spr ay application. phx totoxicity wxas obserxved onl rose, COMpactai holly (F l-'ore 2~). carissa 11ol1y. and c1Umlpo Ia l ( F-icUre 3). S mlptoiulS inll~uded xxvatei- soalked spotting onl a t'ex leav es ot carissa hollx, f aint xx atei spottino on ceaxes of compacta holly, chlorosis 01t IIOill tips o01' mpo alaleas. and mari inal bnrn-1 and en rI il no on rose Ileav es. DueC to an ox erSt gut, roses wxere sprayed Wxhile LFCIde considerable wxater stress; this imay explain the obsei x d phy totoxicity. Onl Sept. 2~3, WI lloxxi no the second spiraxy. phyto- toxicity conuld only be discerned onl the compacta 1o011. As xx i th obserx at ions made Sept. 12', sy mptomls coill si sted ot, xxatei spotti ng onl leaveCs. While the Oils pro ccl to be reltiNely sate' to uIse. they should be Spra yedI inl thc 110Iioig Oi cVCeningL and A 4 NJ ,~- ii 7' Figure 2. IDamaged euumuIacta hoiN(,I branchl (right), coi- pared to branch in controul group. shon Id not be sptrayedc onl wxilted plants. Pirodneris shoul1d axoid sprayitng xxhen ten perat i-1i es ai aboxve 90'F or beloxx 40'F or xxhen relat ix e hum1idity xxill remain aboxve 90(/ for oxver 36 hou1irs. Also. oils arc not compatible xxitlt suIlur based piodcLCt oliar in~l tiect applications, and sexveral i nsectictdes and I'L11n cicides ; oil labels cotntaiit specilfic compatibility ic cautions. Spiax tanks and HIiS esmust be ri nsedl betfore and at ter oil spiray s. Groxxers aire adxvised to test a snmal I nu mber of plants befoie spraying large nimbcrs 01' pklits of' nit kniown ii sea its\ lly totoxiCity shoul1d lppcMa ixthinl 48 hours., Oil sprayIs kill by contact; t hoi r oti-b cox crace of all mt ested plnt scirt alcs is necessary for satis- - f ICt01i i esults. As xx h any pesticide, one Ittust rea~d and Ifolloxx - U.11il label recommrienla- Figure 3. ( urnpo azaleas, comnparison ot ehiorotic grox~ ing tips (four treated rosis in ti' right of' the photo) to " ater spray ed colltri l)ants I t, io r)V~ in the left oif the photo). 7 1 1S and pi eai os I le acithor1s Wxish to t hank Floxxerxxoocl N iiisery, inc.:! Florikan I S.A.. 111C.: anld Sun1 Comlpanly. lIc. t or their assistance xxith ethis projlect. 20 ALABAMA AGRICULTURAL EXPERIMENT STATION Granular Preemergence Herbicides Influence Annual Bedding Plant Growth MACK THETFORD, CHARLES H. GILLIAM, AND GREG CREECH Freshly tilled soils provide an ideal environment for weed seed germination, making the unwanted veg- etation a serious pest in beds of newly transplanted annuals. To control weeds, landscape contractors pre- fer granular preemergence herbicides for their ease of application. While these herbicides can control a va- riety of weeds, they can also injure young transplants. AAES studies found varying degrees of herbicide sen- sitivity among annual bedding plants. In the past few years, several herbicides have been developed for landscape use. Two recently registered herbicides for turf or landscape use are Snapshot 2.5TG (trifluralin + isoxaben) and Stakeout 0.1G (dithiopyr). Since application of these herbicides to turf or woody species may impact nearby annual bed- ding plants, more data are needed concerning the ef- fects of the chemicals. Objectives of this study were to (1) evaluate the effectiveness of Snapshot and Stake- out and (2) assess their phytotoxicity as compared to Ronstar 2G (oxadiazon), Rout 3G (oxyfluorfen + oryzalin), and Southern Weedgrass Control (SWGC) (pendimethalin) on some popular annual bedding plants. METHODS On June 1, 6.9-square-foot plots consisting of a sandy loam soil amended with two inches of pine bark were further ameliorated with ammonium nitrate (34% N) at 120 pounds per acre and tilled to a depth of six inches. Uniform seedlings of begonia, ageratum, nic- otiana, marigold, impatiens, celosia, salvia, geranium, and basil were transplanted on June 6. Each received about one-half inch of water by overhead irrigation. On June 8, herbicides were applied with hand-held shakers at various rates (see tables). All plots received one inch of water via overhead irrigation immediately following herbicide application and as needed. On June 15, half of each plot was over-seeded with large crab- grass (Digitaria sanguinalis L. Scop.) and the other half with prostrate spurge (Euphorbia humistata Englem x Gray). Plots were hand-weeded biweekly to remove any weeds other than large crabgrass and pros- trate spurge. Weedy and hand-weeded controls were included for the purposes of comparison. Data collec- tion included plant injury, plant shoot dry weight, flower number, weeds per plot, and weed shoot dry weight. ALABAMA AGRICULTURAL EXPERIMENT STATION20 1995 ORNAMENTALS RESEARCH REPORT 21 RESULTS Ageratum. Only Rout inflicted significant dam- age to ageratum transplants and injury was propor- tional to application rates (Table 1). Stakeout at two and three pounds of active ingredient per acre (a.i./a.) and Rout at six pounds a.i./a. produced significantly lower shoot dry weights than the hand-weeded con- trol. Shoot dry weights were similar among all other treatments 30 days after treatment (DAT). Shoot dry weights for all plants were equal to or greater than the hand-weeded control by 60 DAT. Flowering of ag- eratum was suppressed 30 DAT with Stakeout at two and three pounds a.i./a. and Rout at six pounds a.i./a.. However, by 60 DAT flower numbers were similar among all treatments. Basil. Plant injury increased with increasing rates of application for both Snapshot and Rout. In contrast to hand-weeded plants, annual shoot dry weights were suppressed with all treatments at 30 and 60 DAT. Only Snapshot gave a rate response in which shoot dry weight decreased as application rates increased. Begonia. Damage to begonia was apparent with Stakeout, SWGC, and Ronstar. Plants treated with Ronstar exhibited severe necrosis, whereas defoliation and stem dieback were observed in plants treated with Stakeout and Rout. Rout-induced injury was proporti- onal to the rates applied. Begonia shoot dry weight was suppressed with Stakeout, Rout, SWGC, and Ronstar as compared to the hand-weeded controls. Begonia treated with Ronstar produced 51% fewer flowers than hand-weeded controls. Celosia. Injury was evident with all rates of Rout 30 DAT, and celosia continued to exhibit foliar ne- crosis 60 DAT with the highest rates of Rout and SWGC. With SWGC, injury increased with increas- ing rates of application. Rout and SWGC also sup- pressed celosia shoot dry weight at 60 DAT. Impatiens. Within 30 DAT, most Rout-treated plants were either dead or severely defoliated. In ad- dition, all rates of Rout suppressed impatiens shoot dry weight. Stakeout, SWGC, and Rout caused increas- ing plant injury with increasing rates. Impatiens re- ceiving the highest rate of SWGC had fewer flowers than hand-weeded plants, and foliage was more sparse. Within 60 DAT, all impatiens except those treated with Rout had similar flower numbers. Marigold. Initially, Rout inflicted slight necrosis in marigolds, but by 60 DAT, there was no significant injury associated with any herbicide treatment. Mari- gold shoot dry weights were similar for all herbicide treatments except Rout, which suppressed shoot dry weights. SWGC repressed the flowering of marigolds early on by 44%. Flower numbers were similar among TABLE 2. LARGE CRABGRASS AND PROSTRATE SPURGE CONTROL WITH SELECTED PREEMERGENCE-APPLIED HERBICIDES AT 15, 30, AND 60 DAYS AFTER TREATMENT Rate' Crabgrass 2 Spurge 2 15 30 60 15 30 60 Stakeout 1.0 .................. 1.0 1.5 2.3 0.4 0.0 0.2 2.0 ..................0.2 0.0 0.0 0.2 0.0 0.6 3.0 ................. 0.0 0.0 0.0 0.0 0.0 0.0 Snapshot 1.53............... 25.5 33.7 26.1 6.0 8.0 9.2 3.0 .......... ..... 4.4 5.9 6.3 0.6 0.4 1.2 6.0 .................. 1.3 1.5 1.3 0.8 1.0 1.2 Southern Weedgrass Control 1.5 ....... .... 5.7 6.9 5.9 1.4 0.8 1.6 3.0.................... 3.6 4.8 1.9 1.0 0.8 1.8 6.0 ...................... 1.7 1.1 0.6 0.2 0.0 0.0 Rout 1.5 ................... 8.0 8.0 8.2 0.6 1.0 2.6 3.0............ 5.9 4.8 4.6 0.4 0.8 0.8 6.0.......... .... 1.2 1.7 0.8 0.0 0.2 0.3 Ronstar 4.0 ..................0.4 1.3 8.0 0.0 0.2 0.2 Non-weeded 0 ................ 176.2 171.4 177.1 43.6 61.8 41.8 'Rates are measures in pounds of active ingredient per acre. 2 Number of weeds per 6.9-foot plot. 3 This rate is approximately one-half the manufacturer's recommended rate and is not acceptable in a commercial landscape setting for grass control. all treatments by 60 DAT. Nicotiana. At highest application rates, Stakeout, SWGC, and Rout inflicted slight to moderate injury on nicotiana 30 DAT. However, by 60 DAT, the Stake- out-treated plants exhibited defoliation and stem die- back, while those treated with SWGC and Rout had not worsened. Snapshot was the only herbicide that did not reduce shoot dry weight of nicotiana, regard- less of application rate. Flower number for all treat- ments were similar except for the highest rate of Stake- out and SWGC, which suppressed flowering. Salvia. Only Ronstar appeared safe for salvia. All other herbicides caused significant injury and sup- pressed shoot dry weight 60 DAT. Geranium. Geranium was generally tolerant of all herbicides evaluated (data not shown). Slight injury occurred with the highest rate of both Stakeout and Rout 30 DAT, but the effects had dissipated by 60 DAT. Flower number and shoot dry weight were not affected by any herbicide treatment. Weed Control. Excellent crabgrass and prostrate spurge control was obtained with most herbicide treat- ments (Table 2). The germination of weed seeds in the Snapshot plots with higher rates and with other herbicide treatments occurred primarily around the base of the transplants, possibly a result of transplants deflecting the herbicide during application. 1995 ORNAMENTALS RESEARCH REPORT 21 22 ALABAMA AGRICULTURAL EXPERIMENT STATION Herbicide-Coated or -Blended Fertilizers Control Weeds and Reduce Pesticide Runoff CYNTHIA K. CROSSAN, CHARLES H. GILLIAM, GARY J. KEEVER, DONALD J. EAKES, AND WILLIAM A. DOZIER, JR. Pesticides in runoff water from container nursery operations pose a possible environmental threat. Pre- vious AAES research showed that when granular her- bicides are broadcast over the top of container plants, 20% to 80% of the herbicides miss the containers and can be washed away by irrigation or rain water. One method of reducing or eliminating nontarget herbi- cide loss would be direct application of fertilizers blended or coated with herbicide to individual con- tainers. A recent AAES study compared herbicide-coated and -blended Nursery Special 12-6-6 fertilizer with standard application methods for prostrate spurge con- trol. Data demonstrated that these new methods pro- vide weed control in containers similar to traditional broadcast applications, while reducing the amount of herbicide runoff to practically zero. METHODS Gardenia augusta 'August Beauty' were grown in full gallon containers in a pine bark:sand medium (6:1 by volume). Media was amended with five pounds of dolomitic lime and 1.5 pounds of Micromax per cubic yard. Plants were irrigated as needed with overhead irrigation. Plants were treated on Aug. 9, 1993. Treat- ments were spread uniformly across the individual containers and seeded with prostrate spurge one week after treatment. To prepare the herbicide-coated or -blended treat- ments, 25 pounds of Nursery Special 12-6-6 fertilizer was placed in a Patterson-Kelley (P-K) Twin Shell Blender. Ronstar (2G and 50WP) and Pennant (5G and 7.8E) were either blended or coated onto the fertilizer at four rates ranging from 2-16 pounds of active in- gredient per acre (a.i./a.). Non-weeded controls were 2 lb. ai/a. D 4 lb. ai/a. l 8 lb. ai/a. * 16 lb. ai/a. D Control * Spray No. weeds 10 8- 6- 4- 27 30 60 90 Days after treatment Figure 1. Spurge number per container with coated Ronstar 50WP. At each date, spurge decreased as her- bicide rate increased. All treatments provided similar or better control than the conventional spray. The con- trol was not weeded or treated with herbicides. 30 60 D 2 lb. ai/a. D 4 lb. ai/a. D 8 lb. ai/a. * 16 lb. ai/a. D Control Broadcast 90 Days after treatment Figure 2. Spurge number per container with blended Ronstar 2G. At the two-pound rate, weed number was greater than the conventional broadcast treatment. The control was not weeded or treated with herbicides. No. weeds 10- 22 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 23 included for comparison, along with a spray and broad- cast application at the rate of four pounds a.i./a. All calculations were based on the surface area of a full- gallon container receiving 6.5 grams of Nursery Spe- cial 12-6-6 fertilizer per container. Blended treatments (Ronstar 2G and Pennant 5G) were mixed by layering the fertilizer with the herbi- cide and blending for about five minutes. Herbicide- coated treatments were prepared by first mixing the herbicide (Ronstar 50WP or Pennant 7.8E) with 100 milliliters of water. This solution was then poured through the P-K Twin Shell Blender funnel and sprayed onto the fertilizer in the shell through pore spaces in a rotating horizontal bar which extends across the cen- ter of the blender. The shell was in continuous rota- tion as the herbicide was sprayed and mixed for about five minutes. RESULTS At rates up to eight pounds a.i./a., Ronstar 50WP- coated fertilizer provided weed control similar to stan- dard sprayed applications (Figure 1). With Ronstar 2G- blended fertilizer, all rates above two pounds provided weed control similar to the broadcast application (Fig- ure 2). S2 lb. ai/a. No. weeds D 4 lb. ai/a. 10 D 8 lb. ai/a. U 16 lb. ai/a. D Control _ U Broadcast 30 60 90 Days after treatment Figure 3. Spurge number per container with blended Pennant 5G. All rates had less weed control than the Ronstar treatments. The eight- and 16-pound rates pro- vided control similar to the conventional broadcast treat- ment. The control was not weeded or treated with her- bicides. Both the Pennant 5G-blended and the Pennant 7.8E-coated fertilizer treatments provided ineffective spurge control (Figures 3, 4). However, the response for a direct container application of Pennant 5G- blended fertilizer was similar to the traditional broad- cast application. Likewise, the Pennant 7.8E-coated fertilizer provided control similar to the spray control. Only the 16-pound rates of the Pennant blended and coated treatments reduced the number of weeds to less than two per container. Fresh and dry spurge weights followed a similar trend to weed number per container, with the lowest spurge weights occurring at the highest herbicide rates (data not shown). Growth indices of Gardenia were not effected by any treatment, nor were there any ob- served phytotoxic symptoms, even when four times the recommended herbicide rate was applied. Ronstar 50WP and Ronstar 2G provided the great- est spurge control at 30, 60, and 90 days after treat- ment (data not shown). There was no difference be- tween the two formulations. However, one concern with the blended (granular) formulation is the poten- tial for separation of the herbicide and fertilizer in ship- ping. D 2 lb. ai/a. No. weeds D 4 lb. ai/a. 10 l 8 lb. ai/a. U 16 lb. ai/a. D Control 8 Spray 6 4 - 2- 0 30 60 90 Days after treatment Figure 4. Spurge number per container with coated Pen- nant 7.8E. All rates had less weed control than the Ronstar treatments. The eight- and 16-pound rates pro- vided control similar to the conventional spray treat- ment. The control was not weeded or treated with herbi- cides. 1995 ORNAMENTALS RESEARCH REPORT 23 Reaction of Dogwood Selections to Powdery Mildew AUSTIN K. HAGAN, CHARLES H. GILLIAM, GARY J. KEEVER, AND J. DAVID WILLIAMS In recent years, widespread outbreaks of the dis- ease powdery mildew, caused by the fungus Oidium sp., have been reported on flowering dogwood throughout the South. In landscapes, disease-resis- tant varieties are an effective, economical, and envi- ronmentally responsible means of controlling this and other diseases of woody ornamentals. A recent AAES study identified a number of powdery mildew-resistant dogwood selections. Se- verity of powdery mildew was assessed in a field planting containing several selections of flowering kousa (Cornus kousa) and Rutgers hybrid dogwood (C. florida x kousa), along with single selections of the giant dogwood (C. controversa) and the pacific x florida dogwood (C. nuttallii x florida) 'Eddie's White Wonder.' There was considerable variation in the severity of disease symptoms in 1994. Symptoms first ap- peared in late spring or early summer, and the dis- ease spread throughout the season. Trees in heavy shade to full sun appeared equally susceptible. The white, cottony growth of the fungus often covered the upper surface of new leaves. Some discoloration and severe distortion of mature leaves was common. Although this blemished foliage is unattractive, it is unlikely that the disease has a lasting effect on tree vigor. Extended periods of mild, humid, and cloudy weather may have contributed to the severity of 1994's outbreak. METHODS Bare-root dogwoods were planted on March 3, 1993, in Auburn into a Marvyn loamy sand soil on 20-foot centers in rows spaced 25 feet apart. Plant- ing holes were dug to a depth of 24 inches. A trickle irrigation system was installed shortly after tree es- tablishment. The dogwoods were grown in full sun and irrigated as needed. Each tree was topdressed with 3.2 ounces of fertilizer (13-13-13) on May 26 and June 24, 1994. Weeds around the base of each tree were controlled with a weed trimmer and directed ap- plications of glyphosate (Roundup). Alleys between each row were periodically mowed. A visual rating of powdery mildew severity was made on Aug. 4, 1994. RESULTS Among the trees screened, cultivars of the flow- ering dogwood (C. florida) generally were most sus- ceptible to powdery mildew (see table). Some dis- coloration of the foliage, premature leaf shed, and severe leaf distortion was commonly seen on the ma- jority of the cultivars of this species. Of these, 16 cultivars were considered highly susceptible. The fo- liage of an additional seven cultivars, including Au- 24 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 25 tumn Gold, Fragrant Cloud, Springtime, Cherokee Chief, Weaver's White, Wonderberry, and Barton's White suffered light to moderate mildew-related in- jury. The absence of symptoms on the foliage of the cultivars Dwarf White and Cherokee Brave indicate that both have excellent mildew resistance. Generally, other dogwoods in the study were more resistant than the majority of flowering dog- woods. Infestations of the powdery mildew fungus on the foliage of the Rutgers hybrid and kousa dog- woods were limited to a few, scattered colonies. No distortion of the leaves or premature leaf drop oc- curred. The pacific x flowering dogwood cultivar Eddie's White Wonder was moderately susceptible. Among the Rutgers hybrids, Ruth Ellen was moder- ately susceptible, while Constellation, Galaxy, Star Dust, and Stellar Pink were highly resistant. All the cultivars of the kousa dogwood, as well as the giant dogwood selection, were highly disease resistant. In summary, dogwoods vary considerably in their sensitivity to powdery mildew. Generally, flowering dogwoods are much more likely to be damaged by this disease than kousa or hybrid dogwoods. Two mil- dew-resistant flowering dogwood cultivars along with a number of disease resistant hybrid and kousa dog- woods are readily available to Alabama consumers. Southern Red Mite Control on Azalea JAMES C. STEPHENSON AND CHARLES P. HESSELEIN The Southern red mite, Oligonychus ilicius (McGregor), is considered to be the most important and destructive spider mite on broad-leaved ever- greens, especially Japanese hollies, camellias, and azaleas. An AAES study was conducted to determine efficacy of labeled miticides, non-labeled pesticides, a numbered experimental compound, and low-envi- ronmental impact materials for IPM programs to con- trol red mites. In addition to the plants listed above, the red mite's host range also includes other plants in the Ericaceae and Aquifoliaceae families. In South Ala- bama, this pest can be found throughout the year, but greatest numbers occur during cooler weather when populations can build up rapidly and cause plant de- foliation. Symptoms of infestation include brownish or bronzed plant appearance which becomes more pronounced with cooler temperatures. These symp- toms reflect plant damage produced by mites feed- ing on the lower leaf surfaces. METHODS Mite-infested Rhododendron x 'Tradition' were selected for a single foliar-applied treatment (see table). Sprays were applied to upper and lower leaf surfaces to runoff on May 18, 1994. No spray adju- vants were used. The azaleas were growing in trade gallon, black plastic containers of an amended pine bark-peat moss medium. Plants were maintained in a vented glass greenhouse under standard horticul- tural practices. RESULTS Seven days after treatment, a number of materi- als provided good control of Southern red mite at the rates listed in the table, compared to the untreated check. Two of these effective pesticides, Sunspray 6E and M-Pede, are considered low environmental impact chemicals. The other effective treatments -- Pentac Aquaflow, Kelthane 35W, Tame 2.4EC + Orthene 75S, and Orthene 75S -- are in different pes- ticide chemical groups. This is beneficial for pesti- cide rotation in a resistance management program. Control with Mavrik Aquaflow, Talstar T&O 10WP, Avid 0.15 EC, Margosan-O 0.3%, and AC 303-630 2SC was similar to the untreated check. No phyto- toxicity was observed with any treatment. I""'~"J~ '~"" ~Vd"'V~' "' ~"' "~~~-I 1995 ORNAMENTALS RESEARCH REPORT 25 26 ALABAMA AGRICULTURAL EXPERIMENT STATION Pesticides to Control Crapemyrtle Aphids GREGORY S. HODGES, MICHAEL L. WILLIAMS, AND ZANDRA DELAMAR Many crapemyrtle varieties are widely used in Southeastern landscape plantings. Throughout the summer, these plants produce colorful blooms rang- ing from white to lavender to bright pink. Crapemyrtle aphid, Tinocallis kahawaluokalani, can be a serious problem on both container-grown and landscape plantings of these plants. An AAES study showed that Orthene 75S provided complete control of crapemyrtle aphids two days af- ter treatment (see table). CGA 215944 provided good to excellent control, with a steady decrease in aphids over time. No phytotoxicity was observed. Crapemyrtle aphids feed on the underside of leaves, twigs, and bud terminals. Heavy infestations can decrease foliage and floral production. In addi- tion to feeding damage, honeydew production pro- motes growth of sooty-mold and mildew on leaves, thus ruining the plant's appearance and reducing plant vigor by decreasing photosynthesis. METHODS In 1994, three pesticides were evaluated for con- trol of the crapemyrtle aphid on landscape plantings of crapemyrtle, Lagerstroemia indica. Test materials were applied on Sept. 28 to 12, eight- to 12-foot-tall plants heavily infested with aphids. In addition to Orthene 75S and CGA 215944, Precision 25 W was tested. Pretreatment counts averaged 193 aphids per leaf. A single foliar spray of each insecticide was ap- plied to runoff using hand-held compressed air sprayers. CRAPEMYRTLE APHID CONTROL BY THREE PESTICIDES Treatment' Rate 2 Mean no. live aphids 3 2 DAT 7 DAT 14 DAT Untreated.................... -- 382 406 260.0 Precision 25 W............ 8 grams 263 660 433.0 CGA 215944 50W ...... 40 grams 94 61 2.0 Orthene 75 S ............... 0.33 lb. 0 0 0.3 'Treatments were applied Sept. 28,1994. 2 Rates are measured in the amount of active ingredient per 100 gallons. 3 Treatments evaluated two, seven, and 14 days after treatment (DAT) by determining the mean number of live aphids per leaf. Pesticides to Control Azalea Lacebugs GREGORY S. HODGES, MICHAEL L. WILLIAMS, AND WILLIAM H. REYNOLDS Southern growers are searching for new ways to control the azalea lacebug (Stephanitis pyrioides), which is common in azalea plantings across the re- gion. It has potential for extensive damage to azaleas in the Alabama landscape due to its ability to repro- duce in great numbers and its relative resistance to some pesticides. In an AAES study, the best control was seen after using Orthene 75S (see table). Orthene 15 G, applied at one or two pounds, was nearly as effective. Orthene 75S and Orthene 15 G at the one-pound rate reduced the lacebug populations greatly after seven days and provided complete control after 14 days. No phyto- toxicity was observed. Lacebugs damage the plant by feeding on the un- derside of the leaves. Extensive feeding on plants by the azalea lacebug will cause a mottling of the upper leaf surface and leaf drop which can detract from the aesthetic value of landscape plantings. In addition, continuous feeding can also cause the plant to be weak- ened and less resistant to disease and winter damage. METHODS In 1993, three pesticides were evaluated for con- trol of the azalea lacebug on container-grown azaleas, Rhododendron indicum. Test materials were applied on Oct. 1 to 24 lacebug-infested plants, potted in three- gallon containers. Orthene 75S and one rate of Orthene 15 G were applied to the potting medium directly. Two additional rates of Orthene 15 G were broadcast ap- plied using a hand-held cyclone spreader. The third pesticide was Merit 2.5% G. 26 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 27 Evaluation of Selected Fungicides for Control of Photinia Leafspot JOHN W. OLIVE, AUSTIN K. HAGAN, AND LEONARD C. PARROTT JR. Photinia leafspot is a common and destructive dis- ease of Photinia xfraseri (red-top or red-tip photinia). This fungal disease attacks the leaves and young stems, causing leaf spotting, defoliation and in severe cases, death of infected plants. In an AAES study, two formulations of Daconil, and Banner sprayed at 14-day intervals provided ex- cellent control of photinia leafspot. Weekly applica- tions of neem oil provided no control; at the end of the study, plants treated with neem oil were stunted and severely defoliated. Triforine was ineffective at controlling the disease. METHODS Healthy, non-infected photinia liners were potted in trade gallon containers in mid-July in a pine bark:peat moss medium (3:1 by volume) amended with 14 pounds of 17-7-12 Osmocote, six pounds of dolo- mitic limestone, two pounds of gypsum, and 1.5 pounds of Micromax per cubic yard of media. Plants were heavily pruned to encourage new growth and were watered daily by overhead impact sprinkler irri- gation. Severely infected photinia plants were placed within the block to serve as an inoculum source and to provide heavy disease pressure. The first treatment ap- plication was made July 26 and continued until the final application was made on Nov. 17. Treatments were applied to runoff with a CO 2 -pressurized sprayer. Disease incidence was evaluated monthly, and the fi- nal rating was taken four months after initial applica- tion (see table). 1995 ORNAMENTALS RESEARCH REPORT 27 28 ALABAMA AGRICULTURAL EXPERIMENT STATION WOODY ORNAMENTALS Chemically Induced Branching of Vinca Minor JAMES T. FOLEY AND GARY J. KEEVER Vinca minor L. (lesser periwinkle), a common vining, evergreen groundcover, is characterized by a prostrate, mat-forming growth habit. Flowers of white, blue, or purple are produced on long runners with few lateral branches. Vinca with multiple runners typically command a higher price. Using more than one cutting or plant per pot requires large amounts of plant mate- rial, while repeated pruning to increase branching is labor intensive. Developing a well-branched plant from a single cutting without repeated pruning should in- crease efficiency of production. Synthetic cytokinins, such as Pro-Shear, Promalin, and Accel, reduce apical dominance, thereby promot- ing the growth of lateral buds. Atrimmec, another plant growth regulator, has both chemical pinching and growth retardant properties. AAES research showed that Promalin and Atrimmec are effective at inducing lateral budbreak and axillary shoot elongation of Vinca. METHODS In an earlier experiment, Pro-Shear and Accel proved ineffective at improving the branching of Vinca (Table 1). Since Atrimmec and Promalin both in- creased the numbers of runners produced, they were selected for further study to determine optimum ap- plication rates. In the followup test, young plants in 4.5-inch stan- dard pots were pruned to five nodes, and all lateral and basal shoots were removed just before treatment. Treatments consisted of a foliar spray of 250-1,000 parts per million (ppm) of Promalin or Atrimmec. Pruned controls were included for comparison. Foliar sprays were reapplied without pruning seven weeks after treatment (WAT). Data collected included pri- mary runner numbers, basal (from the growth medium) runner numbers, primary runner lengths, nodes per pri- mary runner, secondary runners per primary runner, and lengths of the three longest secondary runners. 28 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 OR5 NME~NTALXS RI SI' \R(' RI'IOR I 29 Rie ~T/Imnid/N i//u(is o[,~e' Ne 0//.Iiti R/u~ oilh~ Pim/, km/01 A iiinn plant )/Fii///i i/i/i//e Iii i/iN I/lCl- liCi''-th A' 5 WXAt 7 \ Al I I WATX 16 "'A T Promalin 25 ......... 4.3 4.3 3.7 4.4 7. 17.4 5.6 7.6 500 ............. 5.7 5.7 5.7 5.7 8.8 15.5 8.4 8.1 1000 ...... 6.0 6. 6 7.2 7. 7. 6 6 () 16.4 78 St riin fier 2/50 ..........2. . 3.0 3.2 6.1 17. 1.2 4.8 5001)........... 12 2.2 2.2 2.2 7.5 15.7 1.1 4.6 1,0001 ........3.1 3.1 3.2 3.2 8.3 13.0 I.0) -1. ....... . .... 2,0 6 '/ 2.8 2. 5 6.8 17.2 1.1 4.9 1)il Iclin /e~p/II/~' to Xti inie, in I xpeimIel) I a/nd I xpeimi/nt 2) mn he dLIe 10 SCeIN//i/ differences. Atim e iiifC o t tlteeiNc NNIeii ap[plied toIi 1/1 'f/lil /1i7 \%l I/IN un 1///de/ goo/d p-o\\/ i//i, coni/tiI/n . I \pelii/ei I bean inl the pi In'. M iel ['xpeiriment 2) begn I/I/ihl- 'p//N tieT~ll/e//tN NWeIC ICedpf/lie/.I Nitht~lit pi-1111- I/i/i/i /INCi NZe'.~ttei til/tm/eIt XX XlT) AICtSLHNn ie//n kkeic takeni at 16 N\eek' Itt/il ir/ii/i/e/t. mea' X v c k11 o t the lolg~ Iioidr e/ti//eiiI. R ES IA'S thr-oiL0-It the exper imental period a,, rate ot Piomalin increcased (Table ' at I I WAT. 11-ntber increased tromt 63(/ to 148(/( Fri mary runtner len-th' xere tnot attected by Piontialinl rate at ally Naruipl itlt tittle. IPtotiial in also inl (4091/ oto 1,.400(/ ) and lengths (54% to 59/(). The increase ill Secotndat'yrn nerN- r-eSitied inl noticeably bLl11lr planvt W htch SNib/h1d he mote mat ketable. l Ia l IttIerCI nttmbinets or( the tbtttl'e -olz tluenced by Promial in rate. at teued b) Atrimimec tlroui2It NN ck 1I1 11\CC- IoxxI1~l eNe rne UmberN at H6 WA I ncreased as rate i ncreased. w ith the otre ate st increase (22%' ) trom thle I t) berN, and lenitthN wetre nlot aft tcod I-) Atrimtuec application. The most efttective chemical atl pro- tiottne the branchino ot Vhi'o iN, Pt omlaltn., applied twxice at the tate ot be applted wAhen plants ate actively I; pi .../' ' [// ' t1ro'x tue. jUSI alter prUning" Promalin (right). 30 ALABAMA AGRICULTURAL EXPERIMENT STATION BA-Induced Offset Formation in Hosta GARY J. KEEVER Hosta, a popular herbaceous perennial in the lily family, is usually propagated in the spring or fall by crown division, a process that produces only a few plants per mother plant. The plant's slow propagation rate greatly delays and increases the cost of introduc- ing new hosta cultivars. AAES research has shown that foliar and drench applications of the cytokinin Pro-Shear (BA), a chemi- cal growth regulator, can stimulate offset (plant shoot) development from dormant buds of blue hosta. With- out BA, growth from the plant's crown tends to sup- press development of buds in leaf axils (the angle be- tween the leaf and stem) and in the rhizomes (under- ground stem tissue). Cytokinins induce development of randomly oc- curring buds, break bud dormancy, help lateral buds overcome the dominance of the upper part of the plant, and stimulate elongation of buds in leaf axils. Pro- Shear and other cytokinins enhance shoot formation and branching in both woody and herbaceous plants. METHODS Blue hosta plants in five-inch pots received one of several Pro-Shear treatments: single foliar sprays ranging from 125-2,000 parts per million (ppm) ap- plied to runoff (approximately 0.18 ounce per plant); or single drenches ranging from 5-80 milligrams of active ingredient (a.i.) per pot (Table 1). Several weeks after treatment, plants were transferred to a coldframe and allowed to enter dormancy. Growth index and off- set counts were determined before and after dormancy. Offsets were cut from the mother plants 300 days af- ter treatment (DAT) and placed in open flats of Metro- Mix 360 under intermittent mist; six weeks later, per- cent rooting and root density were evaluated. Increases in offset counts from increased foliar rates of Pro-Shear in the first experiment indicated that possibly optimal rates had not been applied. There- fore, a second experiment was set up to examine the effects of higher spray and drench rates of Pro-Shear. Methods were similar to those in the first experiment, but foliar sprays ranged up to 4,000 ppm, and drenches ranged up to 120 mg a.i. per pot. RESULTS Extensive damage was seen in blue hosta foliage drenched with 80 mg or more a.i. per pot. New foli- age that developed on these plants in 1992 was fre- quently smaller, twisted, or strap-shaped. Symptoms began as a distal bleaching of leaf margins that spread toward the midrib and leaf base. Foliage that devel- oped in 1993 following a period of dormancy appeared normal. No phytotoxicity occurred on plants receiv- ing other drench treatments. Minor tip and marginal bleaching occurred on plants sprayed with 3,000 or 4,000 ppm Pro-Shear, but no phytotoxic symptoms occurred on foliage that developed in 1993. Growth index of plants receiving a single foliar 30 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 O)RNAMEIINTALS RIESEA RCH1 RI' POk S~A p rax an1ot xicli I ca [t I\ at IfIcted by Pi o- Shcar rate inl Experiment I ( Table I. In the second experiment. 11o cIlct waxS Sxccn until 260 DAT. wxhich occurred aft'ci a period of' dormranicy: at this time, growxth index dc- creased wxith increasi ng spray rate (Table 2). G roxwth index I or plants recciv ing a dr ench appl i cation decreased xwith increasing rate 30. 60. and 90) )A'T il both expei ments. This tr end conltinueId 1.n1ti 260 1)AT inl Experiment 2. Alter the dormant period inl Fxpcimcnt I (approximately 3(00 lA)AI. groxxth inl dcx wxax simnilar amlong- all drenlch and Spray treatments. The I ai c decrease inl groxwth indlex of p1 ant x dr enched wxith 80) Ill or more wats primari clue to loss ol' leax es thi-111 ouch il age death. Within 14 daysx ol' treatment, elongation of rhi- /.omic and axilIlary budx wxax ev ident onl plants spray ed xwith 1 .000) ppm or more and onl those drenched xwith 80 ill(, or more. Atall sampling dlatex inlEprmn Iol'Ixet COuntx inICreaxedC Wxith iIelailne la tex Ol' fo0 liai or drenclch appliedl Pro Sheai, and xAcire ximilar f'or the two metChodx l app111ication1 (See f'igure). F xperi- mecnt 2 conItinuedCC this tirend to certain poinlt. but Off- setx cecl med at the hi ehcxt iratex. indicatingL that opti- muoal rates had been exceeded. Fexx or no offx'ets dx el- oped I rml nion treated control PLantx du111i ng either ex per iment. lloxx\l- cx r. I xet COUntx dcreaxedSCC ox c time durl- inco the xeasonl ol, treatmnlt f'or moxt application mleth- odxs iii both cx perimentsx. Thix decrieaxe reflected the abhortioni o' irandom olI xets and may represent another expression ol' phx totoxicitN . A l olloxx up xtUdy (Pace x"ith 2,001 ppin BA, left, comnpared to the cntrl.I 32) later deter mined that off xetxt remoxved ax xteml cut tingx sooin al'ter buid elonLeation COtild be ximccexxf ullly routed. Conxideri ng phx'totoxicitx . plant groxxth, and buld dcx elopment. the optimal ratex o' t'oliar appliedl Pro- Shear rang-ed from 2,000) ppm. the h ighext tested rate ill the fi rxt experi ment, to 3 .(000 ppm inl the xecond. The optimial rate f'oi drench applied Pro-Shear xwax 20 mgl, inl Experiment I and 40 img( inl Experiment 2. Both fol iar and drench applicationx appeared to be eqlUall} ellIectixe. All offxetx cut from the mother plantx and placed Under i ntermuittent mist cx eloped into plantx xxith xxelI dcx eloped root xsystems xxithi n xix xxeeks aifter oftxet remoxval. Thexe data demonxtrate that Uxe ol Pro0 Shear can be an etfecti xc meanx I or met eaxi ng the 11nmer of off xctx inl hoxta. ITii 2. EFUA 'I OF u Siinm IA Fot ixi SiiAIS x~xOR DREM1i 01ii PiiO-mii xi ox, (;iiuxi Ixni~v xm x 01 1i xiiA ('t ,IS i F o 31 1i IlOSi (FLxiTiF 1mx 2) I'oliair A pplicaiions2 2'-9) ................ 20.9 21.0 2I 1. (17. 7 0.4 0. 21)1 ................... 1 . 19.1 19.1 36.8 1 9 1 6 1.0 1 1 1,0 0 ..... ................ 18.9 18.9 M1 ;- 56 3.6 2.9 2.6 3.1 2,00) .............. 19.1 19.1 19.4 36.4 4.1 3.0 2.6 2.6 3110)0).................. 01 10 (1 I20).7 35.4 2.4 4. 6 4.4 4.7 4M .......).....).. 19.7 20.0) (1 33.4 3.6 3.4 2.9 2.6 20 .......................... 22.2 22. -13.33 40.4 2.0 1.7 1.6 2.3 40) ................ 2(0.2 211.3 220. 3 '' 4.6 3. 3.6 4(0 60 ......................... '22.6 21.6 (9.9 35.3 2.9 2.4 2.4 3.1 80)) ................ 201 18.8 8.9 31)4 3.9 3.1 2.9 3.3 11 ................ 198 18.3 181.6 29.8 3.9 3.6 3.1 2.4 20) ................. 24 15.1 14)) -'7.2 4.0 3.9 3.9 2. 0 Cont rol .................18.7 8S8 8.8 40.1 0.( 0( 0.I 10.3 (I o t i i nde CX = (it ewhit + kk iII + i il I t 11 ditI i ~ k dl, ili t i t d~ I p k iLit1)011 . .L11( k) Ii d 1, ii Sx 1) CIpeC I C l lI ii) 1 i di0 ti ix CMe h d ill Celii inl elCl Toliai aplp)icationsi aie lledXSuid ill parix per imillioi. l)ieiilih appilicliolls die lixllc dcc ill mlinaiii ofi dctii e ingredienti per pot. 32 Al- \It \IA \.R I (JI I I RA I I \I RI\]I NI S I kI IWN Offset StagYe of IDevelopment Affects Hosta Propagation by Stem Cuttings G \10o 1 I i 1\1 k. 1) I'l I \ -\I ) 0 11m (1 ii Ii II [\\ Flo Ixincy the e-c study I Pa-c 30fl, Nubh Se (ILflit A A I S ic sca ich x iClIfed a l mtethiod f'oi pro-dtiCiiiLc I ootetf offsets (plait "hioots)I inl less than M NOW ihie huds inlitialfx. Thfis appro t fi ach to lost a propfagation prtiox ides a More rapid met hod , 01f 1um1-tilCationl thanl thi ouch11 annuI-al croxx it ii I Ol. Applications of' the C) tokii n Pr~o- Stages of' (ICNcIlment orI stt Shear MA I cauIsed ailtr reuiioN.I. budIs ill lateral areCas anld inl the bunieIIs ILndici IoLIn1d( Stelin tiNNOIC) to elonegate xx ithin 14 days of' treatmnti inl the PI-C i- onIs 0tnd T()ffsets h'01o theCse bndICS I'oimed xx elf de veloped root N) stemis al'ter hcit cnt from1 moItherI planlt . I foxx cx- e.offset con~nts decreased ox er time (luriliZ the season of treatmnrt. indicatino the ahoi- lionl of, ranidoml off set . The fI f fxx u stl-dx' determIlinedC that off sets reC noxed as steim Cuttings soon ater bndC e1Fneationl con Id he SUicceOSSf fly rooted. This pr-oeednII relot only decreases the tineI requ~i red to increase stock, it axoidIs the loss of ofsets sen oxetr timeI inl the earlI iCi stncfx Unif'orm., singc ex c no offsetsN stock plants of' ble ho0sta xxere tranlsfied-C Onl JIIf\ 13, 1993, f'roml a 47/( lieht eXCIlusion shade houIse to a shaded. double laYer- pof)cthv fene greenhIIIouse' xx ith xeti- fation and heat seipoints of' 78'F" anid 71) 'F espec- tixely. Plants xWere ioxil in fixe inh aialca pots eonitaininc MeXltr-o-Mix 361) and f'crtili/ed three timeis per week NA itli 31)1 par ts per million I ppni) of' nitro- in cuttings treatedI N itl K I B a s thuN aippeared six % ek eil froml 2(10II20) Peteis Peatfite Speeial. On] JL]\ 2). a sinle~ f'ofiar spraN of 2511)ppml Pro Shearkxxasl applied(2( to runofI0 (aIpproIiiiatCIN 0.22 ounIce perI plant. Bnfci -X at 0.2'( wxas added ats a snirtfaetant to the spiray Soflution. Onl Aug". 13. otftsets We rc ent I'I om1 the Mother plants and dix ided inlto f'ourI stem Cutting- groups basedI tiI)0n stage of dcx efopmncrt (SOD) Sol) I - fone1-ated bud. I ist leaf' unfni l-cd: S01) 2 one11 fule1d anld oneC uni ledC leaf: S01) 3 t-xt o unfled-1C leax Cs: anid S( )4)-4 three tint urfedCC leaxvCs. Only Sol) 4 euttingI-s had x isible pref'ormied root initials. Basal ends ( half' inch )of' half' the offIsets iepiesenit- im-, each SOD x cr-c dipped f'or Ii xc seconds inl a I.0 .1))1)11 msolution of' KIB \. a rooting horioim. Steml eutt il ngs Wrcie stiR k inl 804 eel I paeks of' Metro- .Mix 361) medC~ium~ and placedI uIdCI- in~termIittent mIist (three seconlds exe Ii~ fixe intes) Frm 8 am. to 5 pM. Thle stu~dv wxas teri inated onl Sept. 24. and ie- spouse xxas itteasurcd as peicent i notin. pimairy and seconIdaix root counIts,: iroot length, root rating. root dixx cct and shoot SOD)l. 1995 ORNAMENTALS RESEARCH REPORT 33 RESULTS Within 24 days of treatment, numerous offsets had formed on mother plants. Most of these offsets rooted after they were removed from the mother plant and placed under mist for six weeks. All mea- sured characteristics were influenced by stem cut- ting SOD (see table). Percent rooting increased from 56.3% for cuttings removed at SOD 1 to over 90% for cuttings initially at SOD 3 or 4. When the ex- periment was terminated, none of the cuttings had died. It is possible that percent rooting for each treat- ment would have been higher if the rooting period had been extended. Primary and secondary root counts were high- est for cuttings removed at SOD 4, followed by those at SOD 4. These counts were least for those at SOD 1 and 2, which were similar. Compared to SOD 1, primary root counts were 106% higher at SOD 3 and 170% higher at SOD 4; secondary root counts were 296% higher at SOD 3 and 52% higher at SOD 4 (see figure). A similar trend in root dry weight was observed. Root weights at SOD 3 and 4 were 270% and 557%, respectively, greater than those of cuttings removed at SOD 1. Lengths of the three longest primary roots and root ratings were similar for cuttings at SOD 3 and 4, but higher than those of cuttings at SOD 1 and 2. Development of all cut- tings increased during rooting, indicating continued leaf growth. The initial differences in SOD were still present when the experiment was terminated. Of all the root and shoot characteristics exam- ined, only primary root number was affected by KIBA treatment. Primary root counts averaged 8.1 without KIBA and 10.9 with KIBA, a 35% increase. Although other measured root characteristics were not influenced by KIBA, visible root formation was observed sooner on SOD 3 and 4 cuttings treated with KIBA. On Aug. 30, two and one-half weeks after cutting removal, six cuttings from each treat- ment were examined and then reinserted into the rooting medium. Roots were visible only on SOD 3 and 4 cuttings treated with KIBA. This observation suggests a quicker rooting response with KIBA, at least at more advanced stages of development, while data show similar rooting six weeks after offset re- moval. Results suggest at least two alternatives to en- hance rooting. First, cuttings were removed only 24 days after treatment. If cuttings had not been re- moved so soon, it is likely that a higher percentage would be at a more advanced SOD, which should enhance rooting. A potential limitation to this strat- egy would be the decrease in offset counts over time reported earlier; however, this decrease did not gen- erally occur until at least 60 days after treatment. A second approach would be to remove only cuttings at SOD 3 or greater; these cuttings should root readily, and removal may stimulate remaining off- sets to develop more quickly. However, this option may not lend itself to commercial production be- cause of the need to remove offsets more than once during a season. In summary, most offsets stimulated to develop in three and one-half weeks rooted following re- moval from the mother plant and placement under mist for six weeks. Less than 10 weeks were needed to produce rooted offsets from mother plants with no visible offsets. This approach to hosta propaga- tion provides a more rapid method of multiplica- tion than through annual division. 1995 ORNAMENTALS RESEARCH REPORT 33 34 ALABAMA AGRICULTURAL EXPERIMENT STATION Growth and Flowering Response of Butterfly-Bush to Cutless GARY J. KEEVER AND CHARLES H. GILLIAM Rank shoot growth during container production of butterfly-bush necessitates multiple prunings to develop a well-branched, marketable plant. How- ever, most growth inhibitors are either uneconomi- cal or cause undesirable side effects. Flurprimidol, registered as Cutless for use on turfgrasses, reduces shoot growth, apparently by in- hibiting gibberellin synthesis, without causing overt injury. Cutless has effectively suppressed shoot elongation of several tree species when applied as a trunk or subsoil injection and several shrub spe- cies when applied as a foliar spray. Now, AAES research has shown that Cutless also can effectively retard shoot elongation of butterfly-bush; its effect on flower development is minimal at low rates of application. Butterfly-bush is a large shrub, five to ten feet high, that is grown in USDA Zones 5-9. It is char- acterized by rapid growth; long, arching canes; and four- to 10-inch-long fragrant panicles throughout the summer. METHODS Liners of 'Royal Red' butterfly-bush were trans- planted on April 28, 1992, into three-gallon pots of an amended pine bark:sand (7:1 by volume) growth medium. On May 16, plants were pruned to a uni- form height of six inches. Five days later, single foliar sprays ranging from 500-2,500 parts per mil- lion (ppm) of Cutless were applied to the plants until runoff. Plants were topdressed with Polyon 24-4- 16 on April 13, 1993. A second, similar experiment was later initi- ated to evaluate the response of butterfly-bush to lower rates of Cutless, as well as rates that provided effective growth suppression in the first experiment. Cutless was applied as a foliar spray at rates rang- ing from 62.5-2,000 ppm. In Experiment 1, foliar color rating and growth index, as well as inflorescence number, index, and stage of development were determined 30 days af- ter treatment (DAT). Growth indices were also de- termined at 60, 90, and 120 DAT. At termination of the experiment (360 DAT), growth indices and lengths of the three longest shoots per plant were measured. The formula for determining plant growth index is: (height + width 1 + width 2 ) divided by three; width 1 is the widest point of the plant, and width 2 is perpendicular to width . Inflorescence in- dex is calculated by adding the length of the inflo- rescence, the width at the top, and the width at the bottom; this sum is divided by three. 34 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 35 In Experiment 2, growth index and inflores- cence number, index, and stage of development were determined at 45 DAT. Growth index was also measured at 120 DAT and at the termination of the experiment following the 1993 spring growth flush (286 DAT). At that time, the lengths of the three longest shoots per plant were measured. RESULTS Foliar color of plants treated with Cutless was noticeably darker than that of control plants 30 DAT (Table 1). This response is common in plants treated with growth retardants, and in most cases the darker green appearance has been correlated with increased chlorophyll content. Darker green foliage of treated plants was apparent throughout the 1992 season, although foliar color was rated only at 30 DAT. In both experiments, inflorescence number and size decreased with increasing Cutless rates (see tables). In Experiment 1, the decrease in inflores- cence numbers ranged from 16% to 43%, while in- florescence indices decreased 14% to 27%. How- ever, in the second experiment most of the decrease in inflorescence size and number occurred with plants treated with the two or three highest rates of Cutless. Inflorescences of treated plants were no- ticeably shorter, narrower at the base, and more rounded at the apex than those of control plants. The rate at which flowers developed was not af- fected in either experiment. Both experiments confirmed that Cutless can effectively suppress growth, a finding supported by the decreased growth index of treated plants. Mag- nitude and duration of growth suppression was rate dependent. However, rates of 500 ppm or higher were found to be excessive for container produc- tion. Rates of 250 ppm or less provided adequate growth suppression but minimized the negative impacts on flower development. The impact of Cutless lessened over time in both experiments. Retardant-treated plants experience accelerated growth after growth suppression effects have dissipated. This factor may relate to the accu- mulation of large reserves of carbohydrates during the period of growth inhibition. These large reserves stimulate rapid growth as effects of the growth re- tardant lessens. Growth inhibition of control plants, caused by the plants being potbound, could also ex- plain the similarity of all plants in the final days of each experiment. In both experiments, lengths of the three long- est shoots, which typically originated deep within the plant canopy, were similar among treatments. Shoots of treated plants tended to be as long or longer than those of control plants, suggesting simi- lar or greater vigor. Much of the new growth that developed in spring 1993 was upright, rank shoots formed near the base of the plant. Similarities in plant height but a decrease in growth index indi- cated a decrease in plant width with increasing Cutless rate. Findings of these two experiments indicate that Cutless can effectively retard shoot elongation of butterfly-bush, resulting in more uniform, compact plants with dark green foliage. Cutless-treated plants were considered more marketable. The opti- mal rate of application is approximately 225 ppm. 1995 ORNAMENTALS RESEARCH REPORT 35 Growth Control of Asiatic Jasmine and Carolina Jessamine GARY J. KEEVER AND WILLIAM J. FOSTER Asiatic jasmine and Carolina jessamine, two popu- lar evergreen vines, are among the most widely used ground covers in the South. However, these vigorous, twining vines require frequent hand pruning, making them costly and labor intensive to produce. Sumagic, a plant growth regulator, has shown promise for reducing pruning frequency of woody plants in nursery and landscape settings, but plant re- sponse has varied depending on species and applica- tion rate. Its use on Asiatic jasmine and Carolina jes- samine had not been tested. In an AAES study, Sumagic did control shoot elongation of the two vig- orous species, but the rates required are cost prohibi- tive. Hand pruning is probably still the most economi- cal approach. METHODS Asiatic jasmine. An initial experiment in 1988 tested Sumagic spray rates ranging from 75-300 parts per million (ppm), but most of these rates did not suf- ficiently control shoot elongation. A second experi- ment was conducted using higher foliar spray rates, as well as drench applications. In the second experiment, uniform liners were transplanted into one-gallon pots of an amended pine bark:peat growth medium on May 9, 1989, pruned to approximately four inches on June 21, and treated on July 12. Sumagic was sprayed in a volume of two quarts per 100 square feet at rates ranging from 300- 900 ppm. It also was applied as a medium drench at rates ranging from 3-20 milligrams of active ingredi- ent (a.i.) per pot. Because of vigorous vine growth, treatments were reapplied on Aug. 28. Due to exces- sive growth in most treatments and to determine if there was a growth-inhibiting effect following prun- ing, plants were pruned to eight inches after data col- lection 13 weeks after the second treatment (WAST). Data collected included shoot dry weights, length of the three longest runners per plant, and number of run- ners longer than eight inches. Runners shorter than eight inches, a typical pruning length during produc- tion, were considered to be positively affected by Sumagic. Carolina jessamine. Methodology was similar to that used in the Asiatic jasmine test, except that jessa- mine was pruned to approximately six inches after potting. Foliar spray treatments ranged from 75-300 ppm. Growth medium drench treatments ranged from 1-5 mg a.i. per pot. Data collected were shoot lengths, shoot dry weights, foliar color ratings, and root rat- ings. In 1989, researchers conducted a second, simi- lar experiment, which was terminated 13 WAST, instead of 40 WAST. Dry weight RESULTS 40 WAST Asiatic jasmine. In the second ex- O.periment, runner length of Asiatic jas- mine decreased with increasing spray 5.7 rates six weeks after treatment (WAT) 3.9 and 13 WAST (Table 1), but not 40 3.6 WAST. Runner length also decreased 3.7 with drench-applied Sumagic at 6 5.4 WAT, but not 13 or 40 WAST. Data 3.7 suggest a dissipation of growth suppres- 3.1 sion of at least some runners followed 3.3 by accelerated shoot elongation. Run- 2.6 ner lengths of sprayed plants were less ranging up to than those of drenched plants at 6 WAT it growth sup-a and WAST, but by 40 WAST, values d experiment, were similar. Number of runners exceeding eight on Aug. 28, inches decreased with increasing spray d treatment. and drench rates at all sampling dates. Since plants were pruned at 13 WAST, 36 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ()RN \NIF:N'TAS RIESIEARCH REPIORTI T ii 2. Rui 5oiNsi, mi C xmioii lNoJ sS.I~ i Si x S ot (l\'\C~ i N I I IQ5 55As1 495 VIS- sprai' (Ppm) 0 ........ 3.4 6.4 75........3.4 6.4 JO ......2 9 5.6 150 .......27 5.3 10 ...... ' 6 4.6 300( .. .. 2 5 4.5 D~rench I mg ai.i./Ipt) 01 ......... . 6.4 4. 3 ........ 139 5 ........... 23 3.6 Ii c!Iiliielwi' SI ec iliiiiIN aIIT p1 R IT Oi I 16, 1988 and iec aplrcid oil Scepi 22, 1 9 ' ceks ithi ticalilil5 ("AT): WA AST \\hccks aitcr scrriri rrerrruent. the erealci dcci case inl I'III- unr Umbei at 4(0 WAST w xith both spray and drench treatments inldicates that prunling elon-ated shoots ol' SLImIa,1ie treCated plants May enhlance gioxxth SuIppressionI. RLIIInCl numbers we rc si milai t orI sprayed and dlre n che d plants 6 WAT. but We rc less tor drenched plants 13~ and 40 WAST. Fewser elon- stated shoots on drenched plants indi- Cate a more persistent suIppression Compared to sprayed plants. Shoot dry wxeight response to SuLm IIaci treI-atmen IC 1t SxW a SS siIlair to0 th1at o0 r1' c num11I~r1111 her. D~ry\ cxi-hts ol drenchied plants ax ci aged 14% less than those ol' sprayed plants. Foliar Color xx as not at- l'ected by SLumaoic. ('arolina Jessaiiiiiie. Je ssamline showed no obxi oLis I ossth dil TerCeCs among11 plants receivming the dill crent tireatments at 9 WAT. This observ ation wxas su~ppoi ted by the t'act that shoot length at 14 WAT lacked a irate response to either toliar- or drench ap- plied Sinliagic. IlossCCr cxi.CIII~ di uchd l. ax ciammed F'igure I. ( arolina Jessaimine 13 %%eeks after the second toliar application of (left ton right) 300, 600 or 900 ppmn Surnagic; control plant on the right. oxver all irates. \crC shor ter thanl spray ed plants. Shoot drx- xxeights of' essaineFI 19 and 40 WASI de- creased wxith increasino t'oliai and drench rates (Table 2). Howsexver, results sugg(ests a diS- sipation of groswth SuIP- pression ox ci time. At both dates, x ci, ehts of' spray ed plants xx cie Lereater than those ol' drenched plants. Fol iar Col oi xWas u natTfCted by treatments. InI the second Jes- saincll experimIlent. shoot length dcre ased at 6 'AAT and 13 WAST xx ith increasineL rates ot'both f'ol iar- and I s1iv i3. Ri smos mi St \i S(i( (I' Nl xils~v i 2 Rlie Shioot K i''ili 6 WA It ((S I 55 A Spray (ppm) 0( ....... 25.1 65.7 100 ....... 10.6. 6 6(00 .... .... 2.3.9 900).......8.5 12.1 D)renchi O ng adpot I 3 ........ 1 37.8 5 .......... 1 ;. 3'). 0I 6 .....05 8.3 5I.... 6 1 6 9 10 ...... 6 6 7.9 tUCI ohut lol SI I irelicd 'Ti eriioeiis "ercie iitills ip- (shied oil JixIN 12. 1989 arid -e- applied oir A~u" 28. 6.5 xseeks atici iii cairimni Mm AT Ii \V ST S ceksi afet cci id ti caiieni. mcldi um applied SumIaoiC (Table 3). Shoot lengths we rc sii lari onl both dates, re.-ard less of' treatment. Of' all the treatments, toliar spray s of' 300 ppm or drenches ol' three or fixve milli- rams per Pot pioduICed Plants ol the hligheIst CILal itN. They we rc elongated suf- I icientlx to be staked but did not require I reqUent prUnl in-. Also. hii cher rates stUnted the plants and made ti)(211 illteal LundCli/d (sCe I ui-Cs. Figure 2. Carolina Jessaille 13 Nweeks alter the sec- ond medium drench application of (left to right) 3, 5 or 10 ing a.i.Iptt control plant on the right. A It k \1I % kGRIC1 IL It RI k' 1,' RIPElI N I ST I XlION Cutless Controls Shoot Growth of 'China Girl' Holly G xm J. Kmsmmt.(mmt0imimixH. (;ii i i\Ni. t'.)Do-, i i) J.1 EKi 1 Hell it.> are alliolfl the mo3(st wxide ly p1laiited wxoodv IManCkICap plankS inl the SontHea~St. hoit they r'eql~tire re- pealted PRnIing during containier p1 odLICtiOl to Ilainl lain a compact giowxth habit. Noier-Lon cmxx I etar- danltS I haxl C\ beencx ! ted aIS i nhibitorx o1 xxoody planlt O21 -xxth. hot nitSt relaliln LiCconln1lill 01- Caoxe Lill- desirable side ettects. Howev cxer. the retardant I' lrpli t nidol. iregistered as CLOC less- U11se Oil Illl tti Sex, iax redneedCC Shoot 11tiovi WitOx C 1[Sll Vi i ill r ill oti - plLilltS. All AA ES Stodx' shoxxed that ol iai appl ted CotCS lescan elI ect x ely redoiCe Shoot growxth onl 'Clinia Gui' holly dnrling~ COntalilier prOCtioii6 . Lineirs of' 'China Girl' hlolly were transplanted onl Apii 28. I1992, Into sex en-gloll pots oIt an amended p)1ilc bark sand (7:1 by o VOILlMI t(iroxth medi tim1. Onl Maty 14, plaiitS xxere pruniled to aI Uilit'orm height of' 'ix e inchies. Sex en days later, single tol iar sprays rail- 111(2 Iroil 50(0 2,500 pat per million (1)1p111) Ot CntleSS wxere applied to i-1niiol I. Plaiits wtere topdi essed onl April I13, 1993. and tiransplaiited inito 10- gallon pots Oi(111 tn 9. At 364 dlays al'ter treatmlenit (DAT). xwhich 1(11 loxxed thle spi-i no 1993 gr owxth tI Sli. aiid at 534 I AT. mo1(st pk iltI ileeded SOiC le l iiig1 to iii l ox eM CquaZlity. Plnts ere- pIliled to shaZpe. siniilar to the 131 liiillg that occur1sdril typica1 l iii lyI pI-CLotioli 01' xcot otis. ulpr-ight 111)11 c. Cli ppinlgs xxere bagged. dr-ied, anld xxci (lied. Datal collcted i ll oded (2r11Oxtli indelx (sxee tables), ((liar- color ratiliC. and leil(2ths ol, the thiiec longecst shioots per plant. F (lL l ,io F i( I xi ii OF'ii SI ;L O i i ziR% 1h i1Cx '11S '0I DA 1 t60 IAF 900 n110Dex 0 A '4D 0i ....... 057 78.9 82.5 91.1 100.0 99. 500t ...... 6. 65.7 69.4 75.7 105.3 102.7 1000... 61 ( 63.6 0667 69.9 71.1 101.5 1,5 0- .. 60.5 63.9 6(0 (1 65.1 70.9 77.3 2 1000 ... 9.8 6 1 m 6(1(10 65.0 76.4 88.9 -. 5 0 ..... 53. 5 517 54. _2 4. 69 70.9 (I Groh inde\ -(lith + xxclll +it ith ,/3. Wit hi, \\ at the t ici~t 2 AT I days atilet tiatint RLS I LTS Groxt int dex at 310 DAT intdicated a suppressioil of' shoot oroxxtli by CutleSS. Meall x IW aloes lPlr ltt reeivxinog the 50331 ailmd 2.50 pp( PP 11 rates we rc (.214 anld I19(/ less, rexspeetixely. than thiose l'ol- nioiiti eated control planlts (Table I ). Gi oxx ti index decreased Wxithi i[lereaxSILe CtIitSs iate at all other sampling dates. (roxth iiidex ol' planits tireated wxithi 5(0( ppiii Cut cxx wxas 16-17(/K less at (W1 9(1. and I12(1 DAT. At 2.50( pplli groxxth index xx is 32( less ait (3( DAT. 3414 less at 9(1 DAT. and 40K/ lesx at 12(0 DAT. Tlisx iaiLee of' grt-xx tli supp~ression xxax relatixvely conxsistent dum 11ilii the tirxSt gr1OxXill(Z SCaSOli. l3Mitienlam-l l l omlilltS -cccix tlg 500( ppili. The xxideiniig of' the ralige oxver timiie betxxccii 6(0 amid 364 DAT) ret'leeted eOiiti tilCtd rxti oil coiitrol p~lanits aiid almloxt nlo growxthl of' planlts treated xxithi 2,500( ppm CLttexx. Al'ter the xlingi 19913 o2rOWtli lloliS (364 D) , iian gr1owthi inidex ol' planits treated xxith the 500t lpili rate xxax similar to coiitrol plantx. inidicatinge a moitre rapid growxxth irate ol' tireated lplaits. Floxxr cxi.planits treated xxit h ratex abox e 500( plpii had a grxx tli inide x 33.3-46.6K/ lexx at 364 DAT. By 534 DAT. groxtli iiidex ol' planitx treated xx ith 5(0( or 1.111 00013111 CLtlexx xx ax xiiiilar to the econtrol. Growxthl index 01' plaints treated xxithi hi-hler ratex xxax 101.4-22-.9/ les ix.tnch- ealt iii ggroxxtli SLIplIrexxi~ on1 foMa least txx 0 eaxoillx. Al'ter the xlpring 1993 grOxx h I 111sh 1 364 lA)A' . xsioot leng(this ol lilamlt treated xxithi 500( or 1(11 00013111 Cottlexx xxc s imilar to thoxe of eontrol p~lanits (iable 2). Shootx ol' planits treated xxith liielier ratex tended to Figure 1. Reduceed size anid proniouined curli ng lef't) of* 'China Girl' IiollN f'oliage treated xt ith 2,500 ppm (ntles.' *0, 1995 ()RN kNII N I AS RE'SE'ARCH RE PORTI Txtu 2. Etit vtis 01 Simx(.i t Foit tSR Si'Rs. i OF CIi .s1 ON FLiI R COLiOR, SitiOi ILi xi. it, Dxi 10 0A 1 5 1 4 1I) A F 3 U4 0A I' 34 I) VI I ).. ... ... 1 .63. 7. 7 1 1i 1 3 4 M500 -.... .2.3 3.8 8.8 7.5 6.8 1.)1 00 ....29 3.8 6.8 2 (0 5.8 1,500 ...2.8 3.5 5.7 1.7 4. 2,000ll ... 2.8 4.1 0.5 1i5S. F01 C0.T~T~T10 1 tHI: I i-'ll ''TeCTT. 3 IT]CdITTTTT LITel. ,TTTI 'Sh ot engh kthe ITa Icng2th oi the three lIl''e't '1iotTT peT pl1.1 taken .364 t)AT. 1)1\ %k51 t eI'i ,i TT IloolsT i' m cITT\211 Nheii Platsi sxeie IT -LlCCJ ItIT LIT Ti (T Tilt D I)\I TIT ' TIIT at IT .'tiTTcImi be shoirter: those treated wIith 2,5001 ppmi wIere 5414 shoteir than controls. Shoot dry weights ot clippings renmx d 364 DAT deCIcreased I With il]nIcaSi nle Ccii lCss rates: means ranged i'rom 34.21/ to 1 00(4 less ihan the controls. Most of' the decrease in shoot dry WVi eihts OCCenii-cc in plants spiraye V iii rates ahox e 500o ppmr. A somewIhat cliiC icrcnit trend was present at the end ot' 1993. Shoot dix xxCiehtS 01 If prniin"S hiroi1 Plants treated Vwith 50(0 and 1 .0001)1)pp1 C ctless we rc 24.8(/( and 7.2(4 percent greater. respeei ctiey than Contirol Plants. inclicati ng aI greater i gor of' trecated plants. Shocot diy "Ieights ofI plailts treated wit tiiher r ates wsere 23.7(( to 64.9(( less than controls. I Iliagc ol, Plants ircatccd wIith 1.50(0 Ppm Ccitless app)1eared slig1htly smler and 1mor1C cupIpccl than thai oi' Control plants: CiTects We re 1mor1C pro01ned w ith the 2,i000 and 1.500) ppm ratcs (Figure1- I ). Alihocich greater c d~ippn I \,as aipparent wxhcn plants xx cic coin- paredC to Controls, tilc naicira l cLipping( oi' *China Gil" l'OlM icmacic thc cii cci lcss obx idLIS. Beginning ais catl i) s 60 DAT. plants treated kI ith ('utless Werie noticeatbly 11101-C conmpa]ct and cinit'0rill than connrol plants. This efiect VIS sMore pr-1on11cine WIith h1igher i aitCS 0l CLIlCss (Figcires 2-4). Foliaoe colb)i of' Plants treated with Cciilss also was not iceabl\ clarkcr green than thait ol' control plants 30 DAT. Thi di iiercnce in [OHia- Color eon1ti[iiecl ihi ough11ocit I99' aInd 1993. alltl ocigh11 it 'N as less noticeable aIt the end OTI the second season in plants treated xx i th the lowxer ratc , Plants tl"Catcdi Iith CLUci lesWere More comIpact ano 1.n1iioi-11 M.idc atll excep)t f'or those treated wIith 21)000 and 2,500) ppm xx crc considered more marketable. HowvIxer, m1inlimal. piUn i ng l'or shape wxas r-ecli ired t'oi highiest cCIKlity. F'igutre 3. 'C(h ina Girl' holly 90 days afdter treattnti it I Ctttlcss at L;0(1( ppmo. 11 igurc-L 4. '( 161111 (Jii' holly 9(1 daNs after trealttiiut \ it ('utless at 2,500( pp)m. Figure 2. 'China Girl' holly 90 da. ,, after trealinum N% ith Cutless lit 500 ppin . xl\Lktxl \NIko(;RI(t Lt Rki l'\11RINIE'N*i -I If()\ Foliage Characteristics of Selected Red Maple Cultivars .11,i IL. St11I ix. I). Jt IIii i- ( ii im It 11 I. i ~i (, i . i ip k N - iii i x. \\1 ( [,I N L I I I The popuh-1Mii () ti cc e1ltix m'sx is due h) tlieii- uili n-llitx inl nici oi 1all leaf ill or xoiiie other 1ciaini c A trend bo"x ardx inl ereaxWineL 11rOIdLIetioll and uxeo itlllti\aii licexxitaitex (Ilii o natili of, chat actel ix t ics that i each ly ideii- til'y echl CLiliVi. I-exx NIorgan.' 'Nun linod,' 'OctOhcr (,Ior.N,' 'Rtdski H,' 'Red Stms,t' 'Scairsen,' 'Schlesinguri.' ol tliexe chiaracteristics MU I I~or(.' haxC e~ beti catalced to any dcree. (iroxxerx seldom hax e thle OPPOrtunlit\ to cx aILuat n~~ultiple1 eutxr l aspecies iii a sinele location. Oteii the oil]\ obxci x :tioiial data axailable Lix e beeni collcted undetY dHitC l cictcoxx iiicI conditionxS. SuIch iibxei x ationxS aiC dill cult or1 inipoxxiblc to cilipare and iicipiet. AA FS reseatrchieis hiaxve coiipleted a comparati x ex alua1,tioiil 01xelected reCd ma1Zplex. MIM hiic e mouc the 11101xt rcliit\plaiited- landxcape trees. These treexcr erx i1'N\ 11Under the same emi ironmental con- ditionxs ill order to chiaracterize them baxed on heat' Mi)atomiy, . iorpliolog\ , and appearance. N II-:IH 0IDS Cultixarx oh' ied mlapile xx crc obtained inl Match 1988 I'rom Microplant. Ic.. ot Fairx iexx Ore., as tux- xue -cultured micioplant letx. Trees xx erc containeriie.c. LrOxxNN1 tx0 x earx under xCI-tandard nurxerxII~l- prltulic. anld tiransplanted inl Maircli 1990. Tetl cx xx cie hat- x'exted at bitt ai ily 1'rot the miidpoint ol actix\ cN1xxoA inc xhiOOtx h-111 ech ti-Ce inl Ma. July. Aueuxt.1 and Septembher. 1993. A unique fIture oh this xtUdy xxas to compare ied unMIple cu-ltix arx (tt r 1-1ltiiiiit L) pr-ex lOLIxlN repor'ted to perlorm11 xxCl ll thle SoUtheaxt xx ith cultix arx that had not been texted. Iii addition to.A. O&iuhrio cuLtix arx-. thle xtuid\ inluLded selections ol' Fieeman (A. x /n'ecomnii maple cultux arx. xx hich are a cios (lxetxx cen red and xilx cimaphex (A. xort'honiffl(I L. T'hie xtuldy axSo inludedC a[ Oi-Oup oh' xeedling red maplex Ii om xeed collected in I1987 at A. Mc( ill &Son Nurxe-i.cx-C inl Fairic ixx Ore. A./rui 1-1l111Cul1tix aix ilu~ded: 'Autmn111 F-hanie.' xx hichi xxax i illlodlced in 1964: 'Vairx cxx Flitoc, 1992: Fi an k xrcd' ( Red Sn xet) I1966: 'Kai pick.' 1 985: Nomo od.' 1980: 'October (Hoi ' 1961: 'Rcdxkiin.' 1982: 'Schlexin-erl' 1888: and 'I iltord,' 1951I. /A. x /)('c'oioii cuitix ars included: 'Antonio1 111a1c' 'Jell crsied' ), wxhich "x axS mb lodUCed ill 1980: Moi canl' 'Indian Summller-'t. 197 1: and 'Scarxen' (Scarlet Senti- nel). 1972. I eait' xamlex ak~io\ x eetaiken triom ithree additionlI iecd mlaple seleetionxs planted inl a shade tree trial iiti ated inl 1978. These trees liax e not been maintained il thle xame1 1manner~ axS tie cILrrent stUd\ .are h-011 bld- dcii oric-inx., and aire 101 eat x oldi. 'I erel'oic. iesults I ron)l these trees shoulld be interpreted separ ately Ii om tile pre-C iolixiN1\ mlentioiicdl xeect ionx'. [liexe Selectitons xx crc A. N.rc'owoii ' Arnitrone-. 'A. rubl)) '13) o\\ halL' and A~. ibrion 'Ceri inL ' VFor comtparisxon. Ica cx x \ci e collected fromH xilxr ci mples (A. Ntitt /aiorow) inl the xhade tieCC Sttidx RESULTS5 'Scat xen' had lie ha gxtlax cx I ol loxed bx 'NoI) cian and 'Autunin Blac'" (see table). 'Autumn 11F-lame' hadI the xmllexC1t leax \cS. a triMt nloted ill pIC iOus xtnldl lex,. The t'iLente depicts heatf shapex ot' the en It iars cxluteltd inl thisx xtuldx 'October- (ilor-N ' Ii d thle 1le ext petiolex ( leal'xtal kx ) I ol lox d bx 'Iairx cxx\ 1-le': both haxc e ti-iking tecd petiolex tiohi-ou110t the rx ill- xeaxSOn. LtOxx et niti o(cil (N) ci~iceiitiatlolls oc- curredC( wxith Iicedl ingx aiid 'Redxk iii' Ii Ldiet concenl trationx. 'Au-tuniii Flanie.' Thieie Asxo x crc dii lei encex inl bloom ty pe, as shoxxn inl the table. 1995 ORNAMENTALS RESEARCH REPORT 41 Results also indicated that for L red maples grown under the same conditions, the SPAD-502 Chlo- rophyll Meter (Minolta Camera /seedling Co., Ltd., Japan) can be a useful tool for ranking cultivars in leaf greenness. Often leaf greenness is Autumn Blaze ... considered to be highly correlated Autumn Flame ... with foliar N levels, but correla- Fairview Flame...... tions between N concentrations Franksred....... and SPAD-502 values were poor Gerling... ....... Karpick ........ ..... in this study. For example, Morgan.... ...... 'Franksred,' generally accepted Northwood... October Glory ... among growers as having the Redskin......... deepest green color of red maple Scarsen......... cultivars, had one of the lowest Sclesingerl. concentrations of N while having Tilford....................... one of the highest SPAD-502 val- Samples used to obt ues. 2 Leaf area was detern COR Model LI-3050 All stomata (breathing pores) 3 Number of stomata were found on the lower surface with an area of 2.4x1 cultivar, with four fie for the maple selections evalu- 4 Nitrogen levels detei ated. There were fewer stomata 'Chlorophyll content on the sampled silver maple gust and September. on the sampled silver maple 6 Bloom types were de (314,619 per square inch) than on of 1993 and 1994. Pi any of the red maples evaluated. There was no apparent correlation between stomatal density and other leaf characteristics including leaf size. There were 351,529 trichomes (epidermal hair structures) per square inch on the silver maple evalu- ated. No trichomes were evident on the Acer rubrum or A. x freemanii selections in this study. Results from these evaluations define distinctions that characterize foliage features among several red maple cultivars. These data show morphological dif- ferences in a non-subjective way, and may be used for identification purposes. Red Maple Cultivar Performance in the Southeast JEFF L. SIBLEY, D. JOSEPH EAKES, CHARLES H. GILLIAM, GARY J. KEEVER, WILLIAM A. DOZIER, JR., AND JOHN T. OWEN When landscapers and homeowners plant red maple seedlings, they expect rapid tree growth, attrac- tive canopy form, and excellent red fall color. Unfor- tunately, red maples show considerable variations when grown from seed. On the other hand, red maple cultivars, which are cloned from tissue collected from a superior mother tree, are uniform in shape, foliage, and color. However, cultivars are often selected for Alabama based only on evaluations in the plants' native regions. Many of these cultivars prove to be unsuitable for the Southeast. Of the 52 named red maple cultivars, none have been released from selections originating in the southern portion of their native range, which extends from throughout the Eastern U.S. and Canada. To ad- dress this problem, an AAES study identified several superior red maples for the Southeast. Cultivars included in the AAES trials represent a broad cross section of the classified red maples (Acer rubrum L.). Red maple cultivars known to perform well in the Southeast were compared with selections from the Freeman maple group. Freeman maples are generally grouped with red maple cultivars but are recognized botanically as Acer x freemanii, a cross between red maple and silver maple (Acer saccharinum L.). METHODS Cultivars were obtained in March 1988, as microplantlets from Microplant, Inc., in Fairview, Ore., and grown in containers for two years. Trees ranged from four to five feet tall when transplanted in March 1990, into a Cecil gravelly sandy loam soil. 1995 ORNAMENTALS RESEARCH REPORT 41 42 ALABAMA AGRICULTURAL EXPERIMENT STATION Trees were planted on a 30x35 foot spacing and were fertilized with one pound of 13-13-13 per inch of cali- per at planting and in March of following years prior to bud break. Drip irrigation was supplied to each tree based on 100% replacement of net evaporation from a class A pan. Height and caliper measurements were taken through the 1994 growing season. Initial size differences between cultivars were not significant. Foliar fall color patterns were evaluated two to three times weekly from September through December of 1992 and 1993. Growth increases were determined by the difference in current and the previous season's measurements. Acer x freemanii cultivars included 'Autumn Blaze,' 'Morgan' ('Indian Summer'), and 'Scarsen' (Scarlet Sentinel). Acer rubrum cultivars included 'Au- tumn Flame,' 'Fairview Flame,' 'Franksred' ('Red Sun- set'), 'Karpick,' 'Northwood,' 'October Glory,' 'Redskin,' 'Schlesingeri,' and 'Tilford.' Since the traditional TABL practice has been to plant trees varelg from seed, a group of seedlings from seed collected from A. McGill & Son Nursery of Fairview, Ore., were planted for Autumn Blaze ....... comparison. Autumn Flame ......... Fairview Flame...... RESULTS Franksred ................... Cultivars 'Autumn Flame' Karpick Morgan........... (A. rubrum) and three Freeman Nortwood... ..... maple selections 'Autumn October Glory ............. Redskin .... ....... Blaze,' 'Scarsen,' and 'Morgan,' Scarsen................ generally increased the most in Schlesingeri... height over the five years (Table Seedling.......... t ovr Tilford........... 1). 'Northwood' increased the 'Growth increases wer least in height, about one-half measurements. One in that of most other cultivars. Av- is erage annual height increase for Final height 'Autumn Flame' was 117% al avg. 1994 greater than had been reported in , previous studies; 'Franksred,' Scm 9 575 50% greater; 'Scarsen,' 47% 9 571 greater; 'Schlesingeri,' 36% 47 greater; seedlings, 71% greater; S 394 and 'Tilford,' 35% greater. These 9 519 enhanced growth differences 0 386 could be attributed to the use of 3 408 irrigation or own-root trees ver- 9 509 sus budded trees. 78 445 8 542 Caliper increases did not fol- 6 456 low height increase trends (Table the previous season's 2) from 1991 through 1994 as a general rule. While the Freeman group selections had a tendency for height growth typical of silver maple, the caliper growth on an annual basis was different for each. Among the 13 selections of red maple evaluated, 'Au- tumn Blaze,' an A. x freemanii, had the greatest an- nual increase in caliper. 'Morgan' was ranked near the middle, and 'Scarsen' was ranked near the bottom. 'Northwood' and 'Karpick' had the least annual increase in caliper. Most selections developed greater increases in caliper each successive year following establish- ment until 1994. Caliper increases were lower in 1994 than 1993 for all but 'Autumn Blaze.' Fall color duration varied yearly. The longest du- ration of fall color in 1992 occurred with 'October Glory' and 'Fairview Flame' (Figure 1), while in 1993 'Fairview Flame,' 'Schlesingeri,' 'Franksred,' and 'Oc- tober Glory' had the longest duration (Figure 2). Cultivars showed greater variability in the timing of peak fall color in 1992 than in 1993. In both years 42 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 43 'Northwood' and 'Morgan' were the first cultivars to exhibit fall color and to have fall color peaks. How- ever, 'Northwood' had completely defoliated near the time 'Autumn Blaze' was at its peak and before 'Octo- ber Glory' had begun to display notable fall color. Peak fall color was displayed 7-10 days later in 1993 for most cultivars. For the two seasons that fall color evaluations were made, the cultivars 'Fairview Flame' and 'October Glory' had the best display of red col- oration, based on typical color hue and duration, while 'Northwood,' 'Morgan,' and 'Redskin' had poor fall color. Defoliation coincided with the end of fall color for most cultivars each year. While all trees of a par- ticular cultivar developed the same fall color, only 20% of the seedlings exhibited red fall color; other seed- lings had yellow to brown fall color. In a previous evaluation, six of the cultivars used in this study were evaluated for bud union incompat- ibility. Observed deaths of the cultivars in this study from tissue culture were not as prevalent as deaths in the previous study among budded trees. Tree deaths in the previous study, compared to deaths in this study were: 'Autumn Flame,' 11% versus 0%; 'Franksred,' 0% vs. 0%; 'Scarsen,' 55% vs. 0%; 'Schlesingeri,' 78% vs. 40%; and 'Tilford,' 22% vs. 50%. Of the remain- ing cultivars in the current study, one tree each of 'Northwood' and 'Karpick' died. Superior red maple cultivars for the Southeast were 'Autumn Flame,' 'Autumn Blaze,' 'Fairview Flame,' and 'October Glory.' By this same criteria, 'Karpick' and 'Northwood' were poor selections. The Freeman red maple selections, along with A. rubrum 'Autumn Flame,' had the best growth performance with no apparent adaptability limitations to the climate found in this part of the Southeast. Selection R-P O-R-Y R-P R-O O-R Y-B Y-O R-P O-Y Y 0 Y Y-B Typical Sept. Oct. Nov. color 26 1 6 11 16 21 2631 4 9 14 1 9 24 Autumn Blaze Autumn Flame Fairview Flame Franksred Karpick Morgan Northwood October Glory Redskin Scarsen Schlesingeri Seedling Tilford Typical Sept. Oct. Nov. color 22 27 2 7 12 17 22 27 1 6 11 16Selection 11111111111 1111 111 11111 11 111111 11111111 111 11 1 11111 R-P O-R-Y R-P R-O O-R Y-B Y-O R-P O-Y Y 0 Y Y-B Autumn Blaze Autumn Flame Fairview Flame Franksred Karpick Morgan Northwood October Glory Redskin Scarsen Schlesingeri Seedling Tilford Figures 1-2. Hue and duration of fall color for red maple selections in 1992 (top left) and in 1993 (bottom left). Color notation: B = brown; O = orange; P = purple; R = red; Y = yel- low (primary color listed first). = Presence of color. - = Peak color period. Foliar color patterns were evaluated two or three times weekly from September through De- cember of 1992 and 1993 using a modified Munsell Color System. Color peak was the maximum ranking the cultivar attained for the season. Peak color peri- ods were determined to be one observation be- fore the peak date and one observation after the established peak. lu~rrrnurr\r\rr I\/i~rcran nnn Kpncuin nan nr\r\r ta :xhibited red fall color; othe :o brown fall color. evaluation, six of the cultiva evaluated for bud union inc Ty~cal S~et. Oct. I 111 llllllllllnl1ll 11 II II -- mmPf -Yr I - 1995 ORNAMENTALS RESEARCH REPORT 43 * * 1 1*1 I 1 1*1*1*1*1*1*1*1 21 44 ALABAMA AGRICULTURAL EXPERIMENT STATION Buddleia Varieties Root Differently in Response to Rooting Hormone C. CHRIS MONTGOMERY, BRIDGET K. BEHE, D. JOSEPH EAKES, AND TAMMY S. KRENTZ Butterfly bush is a popular perennial landscape plant because it attracts wildlife and is heat and drought tolerant. Both the professional horticulturist and avid gardener may be interested in better methods for propagating this attractive shrub. An AAES study showed that butterfly bush cut- tings rooted readily when treated with the synthetic rooting hormone IBA. Most of the 11 Buddleia culti- vars evaluated were found to root best in the spring and with moderate amounts of the rooting hormone -- 1,500 to 3,000 parts per million (ppm). Cultivars evaluated were Buddleia davidii 'White Profusion,' 'Empire Blue,' 'Black Knight,' 'Royal Red,' 'Opera,' 'Charming Summer,' and 'Pink Delight;' Buddleia davidii nanhoensis 'Nanho Blue' and 'Nanho Purple'; Buddleiafallowiana 'Lochinch'; and Buddleia x weyeriana 'Sungold.' METHODS Three-gallon stock plants were grown for eight months from liners obtained from a single Alabama nursery. Four-node softwood cuttings were taken from stock plants in September 1993 and May 1994 and stored overnight in a cooler at 40 0 F. The next day, plants received IBA treatments ranging from 0-6,000 ppm. For each cultivar, 20 cuttings were used per treat- ment. IBA was applied to the basal 1.5 inches of the stem after the leaves were removed from the lowest node. Treated cuttings were placed in two-inch con- tainers filled with medium grade vermiculite. Contain- ers were placed in a glass-covered propagation house and irrigated by an intermittent mist system for eight seconds every fifteen minutes from 8 a.m. to 5 p.m. Cuttings were evaluated 21 days after treatment for average length of the three longest roots per cut- ting, number of roots, visual root rating, and root dry weight. Shorter, more numerous roots were consid- ered an indication of good rooting. RESULTS Nearly all cuttings rooted in both the 1993 and 1994 studies (see table). The lowest rooting percent- age occurred in 1993 for 'Empire Blue' and 'Royal Red' when no IBA was applied. More cuttings failed to root without IBA than with any treatment. More cuttings failed to root in 1994 than 1993. Overall, 'Royal Red' had the poorest rooting percentage followed by 'Lochinch' and 'Empire Blue.' Other cultivars rooted better. In 1993, root count increased as IBA concentra- tion increased for 'Empire Blue,' 'Nanho Purple,' 'Op- era,' and 'Royal Red.' Root length decreased as IBA concentration increased for 'Pink Delight,' 'Nanho Purple,' 'Nanho Blue,' and 'Lochinch.' The visual root rating increased with higher IBA concentration for 'Lochinch.' 'Royal Red' had the highest visual rating at 1,500 ppm IBA. IBA concentration did not affect root dryweight for any cultivar. For most cultivars, rooting improved as IBA concentration increased. In 1994, IBA concentration increased root count 44 ALABAMA AGRICULTURAL EXPERIMENT STATION 1995 ORNAMENTALS RESEARCH REPORT 45 for all cultivars tested, with the exception of 'Empire Blue' and 'Lochinch.' 'Lochinch' had the highest root count at 3,000 ppm IBA. The root count for 'Empire Blue' was not significantly affected by IBA concen- tration. Average root length decreased as IBA con- centration increased for 'Nanho Purple,' 'Lochinch,' 'White Profusion,' and 'Nanho Blue.' Higher IBA con- centrations increased visual root ratings for 'Nanho Blue,' 'Pink Delight,' and 'Sun Gold.' 'Nanho Purple' had the highest visual rating at 3,000 ppm IBA. Greater dry weights were recorded for roots of 'Nanho Blue' and 'Sun Gold' as IBA concentration increased. 'Lochinch' had the greatest dry weight at 1,500 ppm IBA. Again, rooting of cultivars improved as IBA con- centration increased. Root count on 'Royal Red,' 'Nanho Purple,' and 'Opera' was higher with increased concentrations of IBA, regardless of time of year. However, root count increased on 'Black Knight,' 'White Profusion,' 'Nanho Blue,' 'Pink Delight,' 'Sun Gold,' and 'Charming Sum- mer' in the spring study but not in the fall. IBA con- centration increased root count of 'Empire Blue' in the fall study but not in the spring. IBA concentration decreased root length for 'Lochinch,' 'Nanho Purple,' and 'Nanho Blue' in both studies. Average root length for 'Black Knight' and 'White Profusion' increased in the spring study but not in the fall study. A higher visual root rating was given to 'Nanho Blue,' 'Pink Delight,' and 'Sun Gold' with higher con- centrations of IBA (and 'Nanho Purple' at 3,000 ppm) in the spring study. 'Royal Red' and 'Lochinch' were given higher visual root ratings in the fall study. 'Lochinch,' 'Nanho Blue,' and 'Sun Gold' also showed higher root dry weights in the spring but not in the fall. Most Buddleia cultivars rooted best in the spring after being treated with 1,500 to 3,000 ppm IBA. Comparison of Buddleia Cultivars as Cut Flowers TAMMY S. KRENTZ AND BRIDGET K. BEHE Seven of the 10 butterfly bush (Buddleia) culti- vars examined in an AAES study could be a potential source of cut flowers. 'Charming Summer,' 'Pink De- light,' 'Royal Red,' and 'Sungold' showed the most po- tential. 'Lochinch,' 'White Profusion,' and 'Nanho Blue' proved to have moderate potential. Buddleia is a large, arching shrub that reaches up to six feet in height; dwarf forms often remain below three feet. Its fragrant flower is perfect, usually with an orange mouth, and has a wide range of colors in- cluding pink, purple, yellow, and white. The flower spike ranges from five to 25 inches long. Butterfly bush is an excellent source for cut flowers, since flow- ers are produced on new growth and can be cut heavily each year. The number of flowering stems on the Buddleia depends on cultivar, severity of previous har- vest, and winter conditions. On a three-year-old plant, 60-100 stems could be harvested. Suggested harvest- ing time for butterfly bush flowers is when half the flowers on the inflorescence are open but before the open flowers have started to fade. Flowers should per- sist for five to eight days if properly conditioned. METHODS Flowers were harvested for another experiment on July 6 and 20, 1994, from one-year-old Buddleia bushes in five-gallon containers. The bushes had been pruned in the spring to remove dead flowers and stimu- late new growth. Plants were fertilized weekly with 200 parts per million of soluble fertilizer (20N-8.7P- 16.6K) and irrigated by a drip system. This study began on Aug. 23, 1994, when flower stems were harvested with one- to two-thirds of the flower spike open. Fifteen stems obtained from each of the following cultivars were placed into vases con- taining tap water immediately after harvest: 'Black Knight,' 'Charming Summer,' 'Empire Blue,' 'Lochinch,' 'Nanho Blue,' 'Nanho Purple,' 'Pink De- light,' 'Royal Red,' 'Sungold,' and 'White Profusion.' Within two hours, flowers were transported to a simulated consumer environment and recut under wa- ter. Flowers were placed in vases containing deion- 1995 ORNAMENTALS RESEARCH REPORT 45 46 ALABAMA AGRICULTURAL EXPERIMENT STATION ized water with Floralife at a concentration of 1.3 ounces per gallon. The vase solution was changed every three days to prevent bacterial growth. In the simulated consumer environment, the temperature was maintained between 680 and 72 0 F. The flowers re- ceived light provided by cool white fluorescent bulbs from 6 a.m. to 6 p.m. A ceiling fan provided air move- ment 24 hours a day to maintain a uniform tempera- ture throughout the house. Fresh weight, total length of the flower, open length of the flower, and flower color were measured daily. The flower was considered terminated when the lower one-half of the florets on the spike were shriv- eling and the upper portion of the flower was fading in color. Survival days were defined as the number of days from the initiation of the study until the flower was terminated. Percent open was defined as the per- centage of the flowers which were fully open based on the total length of the inflorescence. Fresh weight change was the daily fresh weight based on the origi- nal fresh weight of the flower. RESULTS 'Sungold,' 'Lochinch,' 'White Profusion,' 'Charm- ing Summer,' 'Royal Red,' and 'Pink Delight' had a similarly high number of survival days (Table 1). 'Nanho Blue' survived fewer days than 'Lochinch' and 'Sungold,' making this cultivar an intermediate cut flower performer. 'Black Knight,' 'Empire Blue,' and 'Nanho Purple' survived the fewest days, making these poor choices for cut flowers. On Day 3 of the study, 'Nanho Purple' and 'Sungold' had similarly high percentages of open flow- ers, while 'Lochinch,' 'Charming Summer,' 'Pink De- light,' and 'White Profusion' all had similarly low per- centages (Table 2). By Day 6, 'Empire Blue,' 'Nanho Blue,' 'Nanho Purple,' 'Sungold,' and 'Royal Red' had similarly high percentages of open flowers. Only five cultivars survived until Day 9, and all were similar. 'White Profusion' had about 80% open, which could be attributed to the more rapid decline of the white flowers. 'Nanho Blue,' 'Black Knight,' 'Empire Blue,' and 'Nanho Purple,' which were moderate to low in survival days, all had more than 95% of flowers open. Since all the cultivars were harvested at one- to two- thirds open, they should all have developed to an ac- ceptable percentage of open flowers. Fresh weight change was not an important factor in this study. Eight of the ten cultivars showed an ini- tial increase in fresh weight, which signals an increase in cut flower mass (Table 3). But 'Nanho Blue' and 'Nanho Purple' then showed a rapid decline in fresh weight, which could be cultivar related and probably contributed to their lower number of survival days. Two cultivars, 'Black Knight' and 'White Profusion,' had no initial increase, and the fresh weight contin- ued to drop rapidly. The decline in fresh weight would contribute to the shorter number of survival days for 'Black Knight' and the lower percent opening for flow- ers of 'White Profusion.' Cultivar had little effect on flower color changes. The quality of most flowers declined at approximately the same rate and eventually reached the lowest color rating, regardless of cultivar. However, 'White Profu- sion' flowers did decline more rapidly due to the more noticeable browning of the white florets. In summary, the following cultivars of Buddleia have an acceptable postharvest longevity and a high percentage of inflorescence development: 'Charming Summer,' 'Pink Delight,' 'Royal Red,' and 'Sungold.' 'Lochinch' and 'White Profusion' could be used with only a slight loss of flower opening offset by a high number of survival days. 'Nanho Blue' could also be a potential cut flower with a slightly lower survival time, but excellent opening of the inflorescence. 'Black Knight,' 'Empire Blue,' and 'Nanho Purple' lack the potential to be cut flowers. ALABAMA AGRICULTURAL EXPERIMENT STATION 46 Response of 'Prize' Azalea to Sumagic Applied at Several Stages of Shoot Apex Development GARY J. KEEVER AND JOHN W. OLIVE When azaleas are forced to bloom, growth retar- dants are applied to restrict lateral shoot elongation, hasten flower bud initiation, promote uniform flower development, suppress bypass shoot development. Plant response to growth retardants depends on time of application and other factors. It is recommended that uniconazole, a triazole retardant labeled for use on azaleas as Sumagic, be applied four to six weeks after final pinch. However, even when applied accord- ing to label recommendations, the desired response may not always occur, due to cultivar differences or variation in light, temperature, or cultural conditions. Ten stages of shoot apex development in forced azaleas have been described, and it was later suggested that performing the various cultural practices based on these stages would make allowances for cultivar, seasonal, and climatic differences. An AAES study evaluated the vegetative and flowering responses of forced 'Prize' azaleas to Sumagic applied at several shoot apex stages of development (SOD). Results showed that it is important to apply Sumagic at a very early SOD. Treatment at a later SOD resulted in less compact plants that flowered later with fewer blooms. METHODS 'Prize' azaleas in 6.5-inch azalea pots containing amended sphagnum peat:softwood shaving (3:2 by volume) growth medium were obtained from a com- mercial grower in November 1991. Plants were im- mediately placed in a glass greenhouse, pruned for uniformity on Dec. 2, and topdressed with 12-4-6 on Dec. 10 and Jan. 10, 1992. When plants were at one of four stages of development, Sumagic was applied on foliage at 15 or 30 parts per million (ppm) in a volume of two quarts per 100 square feet. See the table for a description of SODs and dates of application. On April 28, plants were placed in a cooler and subsequently held in darkness at 38oF for six weeks. Plants were removed from the cooler on June 9 and forced into flower in a shaded double polyethylene greenhouse. Time until flowering was determined from the time plants were removed from the cooler until half the flowers were fully open. At that time, plant height, growth index, flower count and diam- eter, and bypass shoot count and length were deter- mined. The experiment was repeated in 1992. 1995 ORNAMENTALS RESEARCH REPORT 47 48 ALABAMA AGRICULTURAL EXPERIMENT STATION RESULTS Because of similar responses in the two experi- ments, results from only the first test are discussed in detail (Table 1). There were relatively minor differ- ences between the experiments (Table 2), but Experi- ment 2 supported the conclusions of the first test. Differences that were observed probably relate to sea- sonal variability in environmental conditions. In the first experiment, Sumagic was applied in January, February, and March. Flower counts were lower and flowering was less concentrated than in the second experiment, when plants were final pinched in July. Plant height and growth index increased as Sumagic was applied at increasingly later SODs; con- trol plants were the tallest and had the highest growth index. These results were expected since earlier ap- plication of Sumagic should result in a more pro- nounced retardation. Plant height and growth index increments decreased with increasing rate of Sumagic, except for height at SOD 4. Treated plants were com- pact and uniform, particularly those treated at SOD 0 and 1, while control plants were loose, open, and ir- regular in growth habit. Bypass shoot number and length were not influenced by SOD, but they did de- crease with increasing Sumagic rate. Time to flower and flower number varied with SOD and Sumagic rate. Plants treated at SOD 0 or 1 flowered earlier and produced more blooms than con- trol plants or plants treated at a later SOD. When plants were treated at these stages, time to flower decreased and flower number increased with increasing rate of Sumagic. At later stages, time to flower increased and flower number decreased with increasing rate. Plants treated with 15 ppm Sumagic at SOD 2-3 flowered at the same time as control plants, and flower numbers were similar. Plants treated with 30 ppm at SOD 2-3 or at SOD 4 flowered after control plants with fewer blooms Flower diameters of plants treated at SOD 0 or 1 were similar to those of control plants and greater than those of plants treated at SOD 2-3 (30 ppm) or SOD 4. The higher rate of Sumagic did not affect flower diameter at SOD 0 or 1, but it did decrease the mea- surement at SOD 2-3 and 4. A high percentage of plants in these treatments flowered very late and inconsistently; a few blooms opened at a time with no pronounced peak. These plants were considered unmarketable. Results of this study indicate the importance of applying Sumagic when shoot apexes are vegetative (SOD 0) to produce compact plants, hasten flower ini- tiation, and promote uniform flower development. At first, producers should dissect buds to be certain they are vegetative; however, with time vegetative buds will be easily recognizable, and dissection will not be nec- essary. At rates of 15-30 ppm, Sumagic promotes plant compactness, improves flowering, and retards bypass shoot development. A major advantage of this ap- proach is that it avoids differences in response caused by cultivar differences and variations in light, tem- perature, and cultural conditions. These results agree with earlier research on Sumagic and emphasize the multiple role this plant growth regulator may play in the production of forced azaleas. 48 ALABAMA AGRICULTURAL EXPERIMENT STATION Survey of Preferences for Alternative Christmas Trees KENNETH M. TILT, BRIDGET K. BEHE, J. DAVID WILLIAMS, MARY K. GAYLOR, AND J. HEATH POTTER AAES surveys have shown that Alabamians are receptive to using trees other than the traditional Vir- ginia pines, cedars, and spruces as Christmas trees. Surveys conducted in 1993 and 1994 identified an opportunity for the state's Christmas tree and nursery industries to develop and explore this new market for cut or containerized leyland cypresses, hollies, mag- nolias, and other species. With growing concern for the environment, there has been an increase in the demand for living trees, those harvested with the roots for future transplant- ing. Also, when plants are grown in containers, all of the roots are preserved, reducing the problem of needle or leaf drop. To meet this demand, some Christmas tree grow- ers are offering container-grown trees and trees dug from the field that are balled and burlapped. These options allow the grower to sell living trees for Christ- mas or landscape plants throughout the year. Shear- ing hollies, cypresses, magnolias, and other plants into the proper, tapered form not only creates beautiful Christmas tree specimens, it also provides the desired uniformity for landscape designers or architects. How- ever, the trees often sold are not adapted to high tem- peratures common in the South. The customer may end up disappointed and resort to buying an artificial tree. Although the leyland cypress is new to Alabama, South Carolina has had tremendous success with this tree as a Christmas tree. It has a good shape, color, and branch strength, and it does not shed needles. Hollies have long been a symbol of Christmas and have a history of use as Christmas trees. Many of the older survey respondents reported that they grew up using hollies as Christmas trees. METHODS The 1993 survey was conducted at two locations: the Alabama State Fair and the Southern Homes and Gardens Garden Center in Montgomery. Three differ- ent trees were displayed: a cut live Virginia pine, a containerized Nellie R. Stevens holly, and a cut live leyland cypress. All were similar in size and quality. Two trees of each type were used, one of which was decorated. Identical ornaments and decorations were used to prevent judgement by decoration. In 1994, the survey was conducted at the Birming- ham Botanical Gardens and the Southern Homes and Gardens Garden Center. Seven different containerized trees were decorated and displayed: Carolina Sapphire Arizona cypress, leyland cypress, Martha Berry holly, Nellie R. Stevens holly, Fairhope magnolia, Little Gem magnolia, and Springhill magnolia. Using taper, den- sity and color of foliage, uniformity, and distribution of branches as selection criteria, the best trees avail- able for each species were selected. RESULTS Of 119 consumers surveyed in 1993, 55% said they purchased Christmas trees the previous year. Of these, 41% used an artificial Christmas tree, 54% purchased a cut live tree, and 3% purchased a living tree in a container. In the 1994 survey, 66% of 171 consumers said they purchased a Christmas tree in 1993. Of these, 34% used an artificial Christmas tree, 54% purchased a cut live tree, 3% purchased a living tree in a con- tainer, and 2% purchased a ball-and-burlapped Christ- mas tree. 1995 ORNAMENTALS RESEARCH REPORT 49 1993 s 'an'c partici pants repor ted an equlK pi Cfi erenlce lor Virtiinia pine and Ic) land cy press: holly w.xas not tar behind ( Table I ).In 1994, S~Lr\ ey re'411tS s~howxed a stronL, inlert qinl ontainerized Christmas tr ees, especiall I Iy land cy press and hol ly ( Tahle 2) Altho11n1h magnolias and Arizona cy presses w~ere rankedl low, 24-301/ of the participants~ indicated a s~trong prefIerence f or t hese tres More refllned pm nll iln" teehntqneN1C to Cle\ elOP tr ees tat -eted at this market could tillt0\ e Interests ill other alterntativ e (iht txtlax~ trees. Ili 1 994, C01tI-1n met \\ ere atsked it the\ xWLonld hl-l aliC e tree inl a C01ntaitlet that could be p)lanted otide atlter- Chlriqta'l. e\ en l on'11h thexV eost Mote tHan lix e. entt 11 e. Si.t\N tv\ perentt said ve'. xx bile 38(1 still piefletrted the Ik e. ectt trees. li, diloialo/ illgio /1110 (hrsm r111 (lop Ie/?): eccorated Mart/ta BenxY Hol/x, (top center)'., decorou d Ac(//ic, R. Steivn Ho/It (top right); and de(o oald Le hiltd C.\/)JC SN (l VllO dit/ Carol(VinaO SapphI/ire A rizonta CYpresx (bottom). A L k It kNIA k(;R I CI IAJ R k L LAPER IN I FINT STATI ON