1984 Iowa Tuifgrass Research Report Cooperative Extension Service E&lowa State University Ames Iowa 50011 FG 450 July 1984 The following research report is the fourth yearly publication of the results of turfgrass research projects performed at Iowa State University. The first was published for the 1981 field day, which was held June 18, of that year. The others were published in conjunction with the 1982 and 1983 field days. The first cultivar and management studies at the field research area were seeded in August of 1979, and many of these investigations are now in their fifth season. The area has been expanded each year and by 1983 there were 4.2 acres of irrigated and approximately 3 acres of non-irrigated research area. Funding was obtained in 1983 to add 2.7 acres of irrigated research plots to the existing site. This construction should be completed in the 1984 season. The expansion which has taken place since 1979 would not have been possible without the cooperation of the Iowa Agriculture Experiment Station, the Iowa Turfgrass Institute, and the Iowa Golf Course Superintendent^ Association and we would like to thank each of those who have helped to develop the program over the past five years. We would also like to acknowledge Kenneth Diesburg, Brian Maloy, Dorothy Larocque, and the others who have been employed at the field research area in the past year for their efforts in building the program. Nick Christians and Norman Hummel Editors February, 1984 T A B L E OF C O N T E N T S ENVIRONMENTAL D A T A .............................................. 1 TURFGRASS RESEARCH PLOTS, SUMMER 1984 5 NEW FIELD RESEARCH A R E A ........................................ 6 SPECIES AND CULTIVAR TRIALS 1983 Results of High and Low Maintenance Kentucky Bluegrass Regional Cultivar Trials ........................ Kentucky Bluegrass Cultivar Evaluations .................... Regional Perennial Ryegrass Cultivar Evaluation Perennial Ryegrass Cultivar Evaluations Fine Fescue Cultivar Trial 7 12 ............ 14 .................... 16 ............. 18 Kentucky Bluegrass and Perennial Ryegrass Management Studies ...................................... 20 Fine Fescue Management S t u d y ................................ 22 Tall Fescue Management S t u d y ................................ 24 Bentgrass Management Study .................................. 26 FERTILIZER INVESTIGATIONS Evaluation of Different N Sources, Rates, and Timings for Fertilization of Kentucky Bluegrass Turf . ............ 28 Plastic-Coated Urea as a Slow-Release Fertilizer for Kentucky Bluegrass ........................................ 31 Eagle-Iron Stud i e s ......................... 34 Nitrogen X Potassium Study . ................................ 38 Phosphorus Fertilization Study .............................. 40 The Reduction of Ammonia Volatilization from Turfgrass Areas Treated with Surface-AppliedU r e a ................... 42 HERBICIDE STUDIES 1983 Preemergence Crabgrass Control Study ............. 46 1983 Postemergence Annual Grass and Broadleaf Weed Control Study ........................................ 48 1983 Broadleaf Weed Control Studies ................... 50 Selective Control of Tall Fescue in Kentucky Bluegrass with Chlorsulfuron ................................... 52 GROWTH RETARDANT INVESTIGATIONS 1983 Growth Retardant Study ............................ 56 The Effects of Monsanto 4623 2G on Six Cultivars of Tall F e s c u e .......................................... 63 Effects of Six Growth Retardants on the Vegetative Growth of Kentucky Bluegrass .......................... 66 The Use of Mefluidide and PP-333 ........................ 76 TURFGRASS DISEASE RESEARCH Ethylene Production by Bipolaris Sorokiniana Result of 1983 Turfgrass Disease Control Trials . ........ 81 ........ 84 COMPANIES AND O R G A N I Z A T I O N S .......................... .. 87 Environmental Data The next three pages contain information on temperature, rainfall, and growing degree days (GDD) at the Horticulture Research Station in the 1983 season. The growing season of 1983 began with unseasonably cool, wet weather in April, May, and June. The months of July and August were characterized by hot days and very warm nights. This was an ideal season for the development of turfgrass diseases and some severe infestations of Brown Patch were observed on the experimental golf course green at the station. July, August, and September were very dry months for much of Iowa. Some heavy localized thunderstorms at the research station during these months prevented the drought from being too severe (Table AX although these thunderstorms were generally followed by extended periods of dry weather during which irrigation became necessary. Table A. Month Rainfall averages during the 1983 growing season at the Horticulture Research Station, Ames, Iowa. _____________________Rainfall__________________ _ Deviation 1983 Normal from Normal inches------April 3.19 3.19 0 May 5.40 4.50 +0.90 June 9.62 5.80 +3.82 July 7.46 3.24 +4.22 August 4.39 3.60 +0.79 September 2.63 3.20 -0.57 TEMPERATURE 1983 2 RAINFALL 1983 lini 33333344444455555566666677777788888899999900000 01122300112200112200112200112200112200112200112 50505049494949494938383838383827272716161616161 MONTHDfìY 3 1983 GDD COMPARED TO 40 YEARn rP i 11■i ■i 1111111r i ■i 111111' i 1r m i ‘ i *i 111111* i11* i ■i 1r 11111 33333344444455555566666677777788888899999900000 0112230Q112200112200112200112200112200112200112 50505049494949494938383838383827272716161616161 MONTHDRT 4 Wildflower and Native Grass Establishment Study Buffalograss Study Fall Fertilization Study Premium Baron Summer 1984 Baron N & K Study Phosphorus Fertilization Demonstration Tall Fescue Control Study Fine Fescue Management Study Non-lrrigated j Sod Production Study CO >* O N Tall Fescue Tall Fescue Management Study B.G. Weed Control Study Buffalograss Management Study Texoka Common Sharps B.G. Fert. Study Kentucky Bluegrass Cultivar Evaluations Irrigated -------------1 ---------- Irrigated Perennial Ryegrass Management Study Bentgrass Cultivar Study Creeping Bentgrass Perennial Ryegrass Cultivar Evaluations Tall FescueKentucky Bluegrass Seed Mixtures Kentucky1Bluegrass Management Study Non-lrrigated I Baron Growth Retardant Timing Study Parade P. Ryegrass Cultivar Evaluations Turfgrass Research Plots Sod Blend Tall Fescue Control Study Fine Fescue Cultivât Trials I Baron l_ I Sod Re-establishment [_ Study Park Tall Fescue Regional Trials Enmundi Penneagle Penncross Emerald Fungicide Fall Trials Topdressing Study Emerald Penneagle Penncross Iron Nitrogen Study Pythium Control Study Fall Topdressing Study Controlled Release Nitrogen Fertilization Study Growth Retardant Study Park I _______ Iron Nitrogen I Study Sod Establishment Study I N Building 5 Regional Kentucky Bluegrass Study "Low Maintenance” Total Area Map of New Field Research Area Established in the Fall of 1981 ID ID CO *>- ID CM Suipim g 93ueu9;uje|/\| 6 39,215 ft 0.90 Acres « ■> The 1983 Results of High and Low Maintenance Kentucky Bluegrass Regional Cultivar Trials Nick Christians In I98O, the United States Department of Agriculture (USDA) initiated a regional Kentucky bluegrass cultivar trial which is presently being conducted at most of the northern agricultural experiment stations. The test consists of 84 cultivars, with each cultivar replicated three times. Two separate trials are underway at Iowa Sta£e University. One is a high maintenance study which receives 4 lbs. N/1000 ft /yr and is irrigated as ^ needed, and the other is a low maintenance study that receives 1 lb. N/1000 ft in September and is not irrigated. The objective of the high maintenance study is to investigate the performance of the 84 cultivars under a cultural regime similar to that used on home lawns in Iowa. The objective of the low maintenance study is to observe the performance of the 84 cultivars under conditions similar to those which would be used in a park, school yard or other low maintenance area. The low maintenance study was established in September, 1980, and the high maintenance study in August, 1981. There were some unusually severe infestations of leaf spot on Kentucky bluegrass observed in the spring of 1983 in central Iowa. At the research station, it was apparent that these infestations were much worse on some cultivars than others. Ratings were performed on the high maintenance study on April 21, 1983, and the results are listed in Table 1. Kenblue, Nuggett, Baron, Escort, Holiday, and Enoble were observed to be the most severely damaged by the disease. Each of the damaged cultivars had completely recovered from the disease damage by the second week of May. Majestic received the highest quality ratings in the 1983 season (Table 1). Other cultivars receiving high ratings included 243, Midnight, Glade, N535, Ram1, and Bonnieblue. These cultivars also did very well in the milder temperature conditions of the 1982 season. Nugget, which was originally selected for cooler climates, ranked fifth out of 84 cultivars in 1982, and 56th in the higher temperature conditions of 1983. Many of the cultivars which did poorly under high maintenance conditions did well under low maintenance conditions (Table 2). Kenblue ranked 84th under high maintenance and second under low. South Dakota certified, Vantage, and Monopoly also performed relatively better in the low maintenance area. Ram-1 performed well under both maintenance regimes. Notice that these are relative rankings. Kenblue ranked 84th in high maintenance plots but still maintained a better quality than Kenblue with no irrigation and only 1 lb. N/1000 ft . The choice of cultivars clearly depends on the type of care the area is likely to receive after establishment, and proposed use should be carefully considered before cultivars are purchased. 7 Table 1. The 1983 quality ratings for the high maintenance, regional Kentucky bluegrass test established in Fall 1981. Cultivar l. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11 . 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. Maiestic 243 Midnight Glade N535 RAM-1 Bonnieblue Enmundi Bristol Kimono CEBVB3965 Eclipse Barblue PSU-150 PSU-173 Merit Sydsport Victa Fylking 239 PSU-190 Baron SV-01617 Aspen MLM-18011 Holiday Charlotte Eirka WWAg478 Columbia Admiral Escort Cheri Rugby A20-6A Mer pp 300 Mona BA-61-91 Bayside Adelphi Plush Banff Disease* Ratings May** June July Aug 9.0 7.7 8.7 7.7 8.3 7.7 8.0 7.3 7.7 8.0 7.7 8.3 7.3 6.7 7.0 8.0 6.7 7.7 7.0 6.3 6.7 8.0 6.7 7.3 7.7 7.7 6.7 6.7 8.7 6.3 7.0 8.0 6.7 6.7 6.7 7.0 6.7 7.3 6.7 7.0 8.3 7.0 8.3 8.7 8.7 8.0 9.0 8.7 8.0 8.7 8.7 9.0 8.3 8.3 8.3 8.0 7.7 8.3 8.3 8.3 8.0 8.0 8.3 8.3 9.0 8.0 7.7 7.7 8.7 7.3 8.0 8.0 8.3 8.7 8.0 7.7 8.0 8.7 7.3 8.0 8.3 7.3 8.3 7.0 8.3 8.7 9.0 8.7 8.3 8.3 8.0 7.3 8.0 8.0 8.3 7.7 7.3 7.7 8.0 8.3 8.0 8.3 8.3 7.7 8.0 8.0 8.3 7.3 7.3 6.3 8.0 7.3 7.7 7.3 7.0 8.0 8.3 7.3 7.0 8.0 6.7 7.7 7.7 7.7 6.7 7.0 7.0 8.3 6.0 8.7 7.3 7.0 8.0 8.0 7.3 6.0 5.7 7.3 8.3 8.3 8.7 7.0 8.7 6.7 6.3 8.7 7.3 5.7 6.0 7.7 6.3 8.0 6.0 7.3 6.0 8.3 8.3 5.7 7.3 8.3 7.3 7.3 8.3 6.3 7.0 7.7 7.0 8.0 8.3 7.7 8.3 7.3 6.7 7.7 7.0 7.7 7.3 8.0 8.3 6.7 7.3 7.3 7.3 7.3 6.3 7.3 7.0 6.7 6.7 7.3 7.0 8.0 8.0 8.0 6.0 8.0 6.3 6.7 6.3 7.7 6.7 7.0 7.0 6.3 7.7 7.0 6.3 7.0 8.0 6.0 8 Sept Oct Mean 9.0 8.7 9.0 8.3 9.0 8.7 8.0 8.7 8.7 8.3 8.3 8.7 8.7 8.7 8.0 8.0 8.0 8.3 7.0 8.7 8.0 8.0 8.3 7.7 8.0 7.7 8.0 7.7 7.0 8.3 7.0 8.0 8.3 7.3 7.3 8.3 8.0 8.7 8.0 7.7 8.7 7.7 8.3 7.7 8.0 8.0 7.7 7.3 8.0 8.3 6.7 8.7 9.0 ' 8.7 7.3 8.7 7.7 8.3 8.3 7.7 8.3 7.3 7.0 7.7 7.3 7.7 7.3 7.3 8.0 7.7 7.0 7.7 8.0 7.0 7.7 7.7 8.0 8.0 7.0 7.3 6.0 7.0 8.3 7.7 8.4 8.3 8.3 8.1 8.1 8.0 8.0 7.9 7.9 7.8 7.8 7.8 7.8 7.7 7.7 7.7 7.7 7.7 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.5 7.5 7.5 7.5 7.5 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.3 7.3 7.3 Table 1«(Continued) Cultivar 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. Dormie Holiday Welcome Mesa Shasta Apart Vanessa Mystic K3-178 Trenton Touchdown WWAg480 A20-6 Nugget Parade Harmony American Argyle A-34 Enoble 225 K3-179 Kl-152 Geronimo WWAg463 A20 1-13 Merion Mer pp 43 SH-2 S-21 Cello 41 Piedmont NJ735 S.D . Common Wabash Vantage 46 K3-162 80 H-7 Monopoly Lovegreen Kenblue LSD 0.05 Disease Ratings May June July Aug Sept Oct Mean 6.0 5.7 6.0 6.7 8.3 8.3 6.3 8.3 7.3 7.7 7.3 7.7 7.7 4.3 8.3 6.7 6.3 8.0 8.7 5.7 8.3 6.0 8.3 7.7 8.0 6.3 8.3 6.7 8.3 8.7 8.3 6.3 9.0 6.7 7.7 8.3 9.0 8.3 6.7 7.0 6.7 4.7 1.5 6.7 8.3 8.0 8.0 6.3 6.3 7.3 6.0 6.3 6.7 6.0 6.3 7.0 6.0 5.3 7.3 6.7 5.3 6.3 6.3 6.0 6.3 6.0 6.3 6.7 7.3 6.3 6.3 5.7 6.3 5.3 7.0 5.0 6.0 5.0 5.7 5.7 6.0 6.3 6.7 5.3 5.0 1.2 8.3 7.3 8.0 7.3 6.0 6.3 7.0 7.0 7.0 6.3 6.0 6.3 7.7 7.3 6.0 7.3 6.3 5.7 5.7 6.3 6.0 6.7 6.7 6.0 6.0 7.0 6.7 6.3 5.7 5.7 5.0 6.7 5.3 6.7 4.7 5.0 5.3 5.0 7.3 6.3 5.3 4.3 1.0 8.0 8.3 8.0 7.3 7.7 8.3 8.0 8.3 7.3 8.3 8.0 8.0 7.7 8.0 7.3 7.7 9.0 8.0 8.0 8.3 7.7 8.0 6.7 7.3 7.0 7.3 7.0 8.0 7.0 7.3 7.7 7.3 6.7 7.7 8.0 7.0 6.7 6.7 6.3 6.0 8.0 7.0 1.3 7.3 7.0 7.7 7.3 7.0 7.3 6.3 8.0 6.7 7.3 8.0 7.3 6.0 7.7 7.0 6.7 7.0 7.3 7.0 7.0 6.7 7.3 6.7 7.0 7.0 6.7 6.7 7.3 6.7 6.3 7.7 6.3 6.7 7.0 6.7 7.0 6.3 6.3 6.0 6.3 6.7 6.3 1.2 7.7 8.0 6.7 7.7 8.3 7.7 8.0 6.7 8.0 6.7 7.7 7.3 7.0 8.0 7.7 7.3 7.0 7.7 7.7 8.3 7.3 7.7 7.3 7.0 7.0 7.0 7.0 7.7 7.7 7.0 6.7 7.0 7.7 6.3 8.0 7.0 7.0 8.0 7.0 6.7 7.0 6.7 1.4 7.0 6.7 6.7 7.0 7.3 6.7 7.7 6.0 7.7 6.7 7.0 7.0 6.7 7.3 7.0 6.0 7.0 6.7 5.7 6.7 7.0 7.0 7.3 6.7 6.7 6.3 6.3 6.0 6.3 6.0 6.3 6.3 6.3 6.3 6.7 6.0 6.0 6.0 6.0 6.0 5.7 6.3 2.0 7.3 7.3 7.3 7.3 7.3 7.3 7.2 7.2 7.2 7.1 7.1 7.1 7.1 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 6.9 6.9 6.9 6.9 6.9 6.8 6.8 6.7 6.7 6.7 6.7 6.7 6.6 6.6 6.6 6.5 6.4 6.4 5.8 1.0 * Disease ratings are based on a scale of 9 to 1, 9 = no disease infestation and 1 = severe infestation. ** Quality is rated on a scale of 9-1; 9 = best quality and 1 = dead turf. 9 Table 2. The 1983 quality ratings for the low maintenance regional Kentucky bluegrass test established in Fall 1980. May June July Aug Sept Oct Mean K3-162 6.0 Kenblue 6.0 S-21 6.0 Vantage 6.0 S . D . Common5.7 Argyle 6.0 Ram-1 4.7 Vanessa 6.0 Mosa 4.7 Monopoly 4.7 PSU-190 6.3 Plush 5.0 Wabash 6.0 PSU-173 5.3 Piedmont 5.7 Victa 7.3 FyIking 4.3 Enmundi 4.3 Parade 5.0 Harmony 4.3 Mystic 4.0 Eclipse 5.3 5.0 Barblue PSU-150 5.3 MLM-18011 5.3 WWAg478 4.0 BA-61-91 4.7 Baron 6.0 Charlotte 5.3 Apart 4.7 A-34 5.7 Mer pp 43 5.3 K3-179 4.7 5.0 Kimono Dormie 5.3 Aspen 4.7 CEBVB3965 5.3 American 4.7 Mer pp 300 3.7 Enoble 6.3 Bayside 5.7 Escort 5.0 6.0 5.3 6.3 5.7 6.3 5.3 6.0 6.3 6.3 6.0 6.7 6.3 6.3 6.7 5.0 7.0 6.0 6.0 5.7 6.0 5.3 6.0 6.7 6.0 6.0 5.3 5.7 6.3 5.7 5.3 6.3 6.3 5.7 6.7 5.7 5.7 5.7 5.0 6.0 6.3 6.0 6.3 5.7 5.7 6.0 6.0 5.3 5.7 5.7 6.7 5.3 7.0 7.7 6.7 5.3 6.3 5.7 7.0 5.3 6.3 5.7 5.3 5.0 6.0 6.3 5.3 6.3 6.0 5.7 6.0 6.0 5.7 5.3 6.0 5.3 6.3 5.3 5.3 5.7 6.7 6.0 6.3 5.3 6.0 6.3 6.7 5.7 6.3 6.3 6.0 5.0 4.7 5.3 5.0 4.7 5.0 4.3 5.0 4.7 4.3 4.3 4.7 4.7 4.3 6.3 4.7 4.3 4.7 4.0 4.7 4.3 4.0 4.7 4.7 3.7 4.3 4.3 4.3 4.3 3.7 3.7 4.3 4.3 3.7 4.7 4.0 7.7 7.7 6.3 6.7 6.7 6.3 5.7 4.7 5.7 5.0 3.3 5.0 4.7 4.7 5.7 3.0 5.0 4.7 5.3 5.3 5.7 4.7 4.3 4.7 3.7 4.7 4.7 3.3 4.3 4.7 4.3 3.7 5.0 3.7 4.7 4.7 3.7 4.3 4.3 3.3 4.0 4.0 7.0 6.3 6.0 6.0 6.3 6.3 6.0 4.7 5.7 4.3 3.0 4.0 4.7 3.3 4.7 2.3 5.7 4.3 4.3 5.3 4.3 3.7 4.0 4.0 4.7 5.3 5.0 3.7 3.7 4.3 4.3 3.7 4.7 3.0 3.3 4.7 4.7 3.7 4.3 3.0 3.3 3.7 6.4 6.3 6.1 6.1 6.1 5.9 5.5 5.5 5.5 5.3 5.3 5.3 5.2 5.2 5.2 5.2 5.1 5.1 5.1 5.1 5.1 5.1 5.1 5.0 5.0 5.0 5.0 4.9 4.9 4.9 4.9 4.9 4.9 4.8 4.8 4.8 4.8 4.8 4.8 4.8 4.8 4.8 Cultivar l. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 10 Table 2.(Continued) Cultivar 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. May June July Aug Sept Oct Mean Adelphi Birka Trenton Touchdown Welcome Merit Shasta SH-2 NJ-735 Merion Admiral Cheri 239 SV-01617 Banff Geronimo WWAg463 Bono Midnight Sydsport Lovegreen K3-178 Kl-152 Rugby Majestic Bonnieblue Glade WWAg480 Cello N535 Mono 225 A20 H-7 Columbia Bristol 243 Nugget K3-179 Holiday 1-13 A20-6A 4.7 4.3 5.0 6.0 4.3 5.3 5.3 6.0 6.7 5.0 5.0 5.0 5.0 4.3 4.3 6.0 5.0 5.0 5.3 6.0 4.7 5.3 4.5 4.3 5.3 4.7 4.7 5.3 5.3 4.7 5.3 5.0 5.0 4.7 5.0 5.7 5.3 5.0 5.0 4.3 5.7 4.3 6.0 5.7 5.3 6.3 5.7 6.0 6.3 7.0 6.7 5.7 6.0 5.0 5.7 6.0 6.0 6.0 6.3 6.0 6.0 6.3 6.0 6.0 6.0 6.0 6.3 6.3 6.0 6.0 5.3 5.3 5.7 5.7 5.7 6.3 5.3 6.3 6.0 5.7 5.7 5.7 6.0 5.7 5.0 5.3 6.0 5.7 5.0 5.7 5.7 5.3 5.7 5.0 5.3 5.0 5.3 5.3 5.3 6.0 5.7 5.7 5.3 6.3 5.7 6.0 5.0 5.3 6.3 5.0 5.7 6.0 5.7 6.0 5.7 5.7 5.0 5.3 5.0 5.7 5.3 5.0 5.0 5.7 5.3 5.0 4.0 3.7 4.0 3.3 4.3 4.0 3.7 3.7 2.7 3.7 4.3 4.7 4.3 4.0 3.7 3.0 3.0 4.3 3.3 3.7 3.3 3.3 3.0 3.7 3.0 3.3 3.0 3.0 2.7 3.7 3.3 3.7 3.3 3.0 3.3 3.0 3.0 3.0 3.3 3.0 2.7 2.7 4.7 4.0 4.0 3.0 4.3 3.7 3.3 3.0 3.0 4.3 3.7 4.0 4.0 4.3 4.0 3.3 3.3 3.3 4.0 2.7 3.7 3.3 4.5 3.7 3.0 4.3 3.0 3.0 4.0 3.3 3.3 3.0 3.3 3.0 3.7 2.7 3.0 3.3 3.3 3.3 2.3 3.0 4.0 5.3 4.0 4.0 4.7 3.7 3.7 3.0 3.3 4.7 4.0 3.7 3.3 3.7 4.3 3.3 4.3 3.3 3.3 2.7 4.3 3.3 4.5 4.0 3.0 3.3 4.0 3.0 3.3 3.3 3.3 3.7 3.3 3.3 3.7 2.3 2.7 3.0 2.7 2.7 2.7 2.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.5 4.5 4.5 4.4 4.4 4.4 4.4 4.4 4.4 4.3 4.3 4.3 4.3 4.2 4.2 4.2 4.1 4.1 3.9 LSD 0.05 1.6 1.2 0.5 1.6 1.8 2.0 0.8 Quality is rated at 9:=best quality and l=dead turf. higher constitutes acceptable quality. 11 A rating of 6 or Kentucky Bluegrass Cultivar Evaluations Nick Christians The 49 Kentucky bluegrass cultivars located in section two of the turfgrass research area were seeded in the fall of 1979. These plots were fertilized at a rate of 4 lb. N/1000 ft (urea) in both the 1980 and 1981 seasons and with 4 lb. N/1000 ft (SCU) in 1982 and 1983• No insecticides or fungicides have been used on the area. Irrigation was applied as needed to prevent drought. The results of 1983 evaluations are listed in Table 3. The values listed under each month are the averages of ratings made on three replicated plots. Yearly means of all the months in which data were taken are listed in the last column. The first cultivar received the highest average rating for the entire 1983 season. The cultivars are then listed in descending order of average quality. Infestations of leaf spot on Kentucky bluegrass were quite severe at the research station in April, 1983. Among the most seriously affected cultivars were Sving, Kimono, Ram-1, Merit, and Midnight (Table 3). No evidence of the early spring disease infestation was present in May when the first quality ratings were performed. Midnight received the highest overall rating in 1983. It was followed in order by Ram-1, Glade, Enmundi, and Mystic. Midnight and Ram-1 were two of the cultivars which were most seriously affected by leaf spot in April and yet received the highest overall quality rating for the season. It is always very important to evaluate performance over an extended period of time and not judge acceptability on single observations. 12 Table 3 . The 1983 quality and disease ratings for the Kentucky bluegrass cultivars established in the fall of 1979. Cultivar i. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. DiseasedRating Midnight Ram I Glade Enmundi Mystic Nugget America Escort Arista Bristol Adelphi Merit Senic Aspen N535 Victa SV01617 Barbie Baron FyIking Pennstar Merion K3-160 Kimono Cheri Birka Bonnieblue Vantage Aquilla A-20 Parade Sving Fanfare Touchdown Sydsport Rugby A-20-6 K7 6-86-4 Plush Majestic Common Columbia Trenton Park BFB-35 A-34 WTN-1-13 Wabash WTN-H-7 5.6 5.0 7.0 8.0 6.7 3.6 9.0 7.3 5.6 7.7 9.0 5.3 7.3 9.6 8.0 6.7 6.0 7.3 6.0 6.0 7.3 7.0 9.0 4.3 9.0 7.3 8.5 8.5 6.0 7.7 9.0 3.6 8.5 7.3 8.0 9.0 6.0 8.5 7.3 8.5 8.5 8.5 8.5 8.5 8.5 8.5 9.0 8.5 7.3 1.5 LSD 0.05 1 - Disease ratings are and l=severe damage. 2 best quality, l=poorest May June 9.0 8.0 7.7 8.0 7.7 8.3 8.0 8.4 7.3 7.3 7.3 7.7 6.0 7.2 7.3 7.0 6.8 6.5 7.7 7.0 7.0 6.3 5.7 7.3 6.7 7.3 6.3 6.0 6.5 7.0 6.3 7.3 6.0 6.7 6.3 6.8 7.0 5.7 7.5 5.8 5.0 6.2 6.0 5.0 6.3 6.3 6.3 5.3 6.0 8.7 8.0 8.3 8.0 7.3 8.7 7.3 7.3 7.3 7.0 7.7 7.7 6.7 6.7 7.3 7.7 7.0 7.0 7.0 6.7 7.0 6.3 7.0 7.0 6.7 7.0 7.0 6.3 6.0 7.3 6.0 7.7 6.7 6.0 6.3 6.7 7.3 6.3 7.0 6.0 6.0 6.0 6.7 5.3 6.3 6.7 6.7 6.0 7.0 Quality Rating^ Aug July 9.0 8.7 9.0 9.0 9.0 8.3 8.3 8.7 9.0 9.0 8.7 9.0 9.0 9.0 8.3 9.0 9.0 8.7 9.0 9.0 9.0 8.7 9.0 8.7 8.7 9.0 8.7 9.0 8.7 7.3 8.0 8.0 9.0 9.0 9.0 8.0 7.3 9.0 7.7 8.0 9.0 7.7 7.3 8.7 7.7 7.3 7.3 8.3 7.0 8.3 7.7 7.7 7.7 8.3 7.0 7.7 8.0 7.0 7.7 7.7 7.3 7.7 7.7 8.0 8.0 7.7 8.0 7.7 7.7 7.3 8.3 7.7 6.3 8.0 6.7 7.5 7.5 7.7 8.0 7.3 6.7 7.7 6.0 7.7 6.3 7.0 7.7 6.3 7.3 8.0 6.7 6.7 7.7 7.0 7.3 6.7 6.7 6.0 Sept Oct Mean 9.0 9.0 8.7 8.7 8.3 8.0 8.7 8.7 9.0 8.7 8.7 7.7 9.0 8.3 8.3 7.7 9.0 8.3 7.7 8.3 8.0 8.3 8.3 8.0 7.3 8.3 8.0 7.7 8.7 7.3 8.3 7.0 8.3 8.7 7.0 7.3 7.3 7.3 6.7 8.0 8.0 8.0 7.3 7.7 7.3 6.7 7.0 6.7 6.7 9.0 8.7 7.7 8.0 7.7 8.3 8.3 8.3 8.3 8.3 8.0 8.7 9.0 8.3 8.3 8.0 8.0 8.3 7.7 7.7 7.7 7.7 8.0 8.3 8.0 7.3 8.3 8.3 7.7 7.7 8.3 8.0 7.0 7.3 7.0 8.0 7.3 7.3 7.3 7.7 6.0 7.3 8.0 7.3 7.0 7.3 6.7 7.0 6.3 8.8 8.3 8.2 8.2 8.1 8.1 8.1 8.1 8.0 8.0 8.0 8.0 7.9 7.9 7.9 7.9 7.9 7.8 7.8 7.7 7.7 7.6 7.6 7.6 7.6 7.6 7.6 7.5 7.5 7.4 7.4 7.4 7.4 7.3 7.2 7.2 7.2 7.2 7.1 7.1 7.0 7.0 7.0 6.9 6.9 6.9 6.8 6.7 6.5 1.2 0.5 0.9 1.0 0.5 0.8 1.0 based on a scale of 1 to 9; 9=no visible symptoms - Quality ratings are based on a scale of 1 to 9; 9= quality, and 6=acceptable quality. 13 Regional Perennial Ryegrass Cultivar Evaluation K. L. Diesburg and N. E. Christians This trial is part of a national study coordinated by the USDA. It was established during September 1982 in conjunction with several identical trials across the country. The purpose is to identify regional adaptation of the 48 cultivars tested. Cultivars are evaluated each month of the growing season for turf quality and disease infestation. The average yearly performance of a cultivar is most important. 2 The trial is maintained with 4 lb. N/1000 ft through the growing season and is irrigated as needed. Standard, single applications of preemergence herbicide in May and broad-leaf herbicide in September are used to prevent weeds. The entire area is maintained at a 2-inch mowing height. A disease epidemic typical of Dreschlera siccans occurred in October 1983. The causal organism was not confirmed. Eleven of the 48 cultivars were severely discolored while all cultivars showed at least a little discoloration. Many of the top performers in 1983 were among the cultivars showing the least disease symptoms. As indicated by the experiment means at the bottom of Table 4, the cultivars, in general, were sensitive to environmental changes. They performed exceptionally well in September and moderately well in October. During July and August, however, the prolonged heat lowered overall quality dramatically. The top six cultivars in the Mean column were exceptional in that they looked good consistently throughout the season. 14 Table 4. Turf quality and disease ratings of perennial ryegrass cultivars Quality Cultivar 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. Manhattan II Palmer GT-II BT-I(Tara) Prelude LP 702 M382 HR-1 2ED Yorktown II HE 168 Ranger Fiesta SWRC-1 Regal Acclaim HE 178 282 Citation Cigil Delray Omega NK 80389 Derby Diplomat Gator LP 736 LP 792 NK 79309 Pennant Pennfine NK 79307 IA 728 Blazer Dasher Elka Birdie Crown WWE 19 2EE Manhattan Barry LP 210 Premier Cockade Cupido Pippin July 9.0 9.0 8.0 7.3 8.3 7.7 7.7 9.0 8.0 7.3 7.0 7.3 7.0 7.3 8.7 6.3 6.3 6.0 8.3 7.0 8.0 6.3 6.3 7.3 6.7 5.7 6.7 6.7 6.7 7.0 7.0 8.0 6.7 5.7 6.3 5.3 6.0 5.7 5.7 5.3 4.3 5.0 4.0 6.3 4.0 4.0 3.7 Aug 8.0 7.7 7.0 7.0 6.7 6.7 6.0 6.3 6.0 6.3 7.7 6.0 5.7 6.3 6.7 7.0 6.3 7.0 5.7 6.0 6.7 6.0 6.3 6.3 5.7 6.3 5.3 6.3 6.3 6.3 5.7 6.3 6.3 6.0 5.0 5.7 5.7 5.7 6.0 6.0 5.3 5.3 6.0 5.3 5.3 4.0 3.7 Sept 8.7 9.0 9.0 9.0 9.0 8.7 9.0 8.3 8.3 8.7 8.0 8.7 9.0 8.7 8.3 8.3 8.3 8.3 9.0 8.0 7.0 8.3 8.3 7.7 8.3 9.0 8.3 8.0 8.7 6.7 7.0 8.7 6.7 8.0 8.0 8.3 7.0 7.7 6.7 8.0 8.3 9.0 7.3 7.7 7.3 6.0 5.0 15 Oct 8.7 7.7 8.7 8.3 7.3 8.0 8.0 7.0 8.0 7.7 7.0 7.7 8.0 7.3 6.0 7.7 8.0 7.7 6.3 7.3 6.7 7.3 7.0 6.7 7.0 6.7 6.7 6.3 5.7 7.3 7.7 4.0 7.7 6.7 7.0 7.0 7.7 7.0 7.7 6.7 8.0 6.3 7.7 5.7 6.7 7.3 6.3 Mean Disease 8.6 8.3 8.2 7.9 7.8 7.8 7.7 7.7 7.6 7.5 7.4 7.4 7.4 7.4 7.4 7.3 7.3 7.3 7.3 7.1 7.1 7.0 7.0 7.0 6.9 6.9 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.6 6.6 6.6 6.6 6.5 6.5 6.5 6.5 6.4 6.3 6.3 5.8 5.3 4.7 7.0 5.3 7.3 7.0 6.3 6.7 6.3 5.7 6.7 6.3 6.3 5.7 6.0 5.7 4.7 7.3 7.0 7.0 4.7 5.3 5.7 6.0 4.7 5.0 5.7 5.3 5.3 5.3 3.3 6.7 6.3 2.3 6.0 5.3 5.7 4.7 6.0 5.0 7.3 6.0 6.3 4.0 6.7 3.3 5.3 6.7 5.3 Perennial Ryegrass Cultivar Evaluations Nick Christians The 22 perennial ryegrass cultivars in this trial were among the first plots to be established after the renovation of the field research area in 1979. The study has been maintained since^that time at a 2-inch mowing height and is fertilized with 4 lb. N/10Q0 ft /year. The area receives no fungicide or insecticide applications. Results of winter damage evaluations and yearly quality ratings are listed in Table 5. Winter damage can be a serious problem for perennial ryegrass cultivars. The data listed were taken in spring, 1983. The values in the table represent the percent of the plot area damaged; 100 = total kill and 0 = no damage. NK-100, Delray, and Pennfine were observed to be damaged to the greatest extent. The damage evaluations were performed in early April. By May, most of the cultivars had completely recovered from winter damage. Regal, Derby, Manhattan, and Belle received the highest overall quality ratings in 1983. However, there was little observable difference among the first 17 cultivars listed. Only NK-100 and Linn were determined to be unacceptable for the entire season. Caravelle, NK-200, K5-94, and Goalie were observed to be unacceptable at certain times during the season but received acceptable ratings for the season as a whole. 16 Table 5. The 1983 quality ratings for perennial ryegrass cultivars established in 1979 . Cultivar 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. Regal Derby Manhattan Belle Blyes Citation Pennfine Diplomat Loretta Fiesta Med North Yorktown Goalie Elka Delray J186 R24 K5-88 K5-94 NK-200 Caravelle AIK-100 Linn LSD 0.05 Winter Damage 0 8 7 8 8 8 10 0 0 10 0 ' 0 0 7 10 3 8 0 3 10 40 0 ______________Quality Rating May June July Aug Sept Oct MEAN 7.3 6.7 7.3 7.0 7.3 6.7 6.7 6.3 7.3 6.7 6.3 7.0 7.0 7.3 6.3 7.3 6.3 5.7 7.3 5.7 5.0 3.7 7.7 7.3 6.3 6.3 7.0 6.3 6.3 6.7 8.0 7.0 7.3 7.0 5.7 8.0 6.7 6.3 6.7 6.0 6.3 6.7 4.7 4.0 8.0 7.7 7.7 7.7 7.3 8.0 8.0 8.0 7.7 7.0 8.7 8.3 7.0 6.7 7.7 7.7 7.7 7.0 7.0 7.0 5.3 4.3 8.0 8.0 7.7 8.0 7.0 7.3 7.3 7.7 7.3 7.7 6.3 7.7 7.3 7.0 7.0 6.7 6.7 7.0 5.7 5.7 4.0 3.0 9.0 8.7 8.7 8.3 8.7 8.0 8.3 7.7 7.0 8.0 7.0 6.3 8.0 6.7 7.0 6.7 7.3 8.0 7.0 6.0 4.3 3.3 9.0 8.3 8.3 9.0 8.3 9.0 9.0 9.0 7.7 8.7 9.0 8.3 8.7 8.0 9.0 8.7 8.7 8.7 7.7 9.0 7.7 6.7 8.2 7.8 7.7 7.7 7.6 7.6 7.6 7.6 7.5 7.5 7.4 7.4 7.3 7.3 7.3 7.2 7.2 7.1 6.8 6.7 5.2 4.2 1.2 1.1 1.4 1.2 1.3 1.1 0.7 Quality is rated on a scale of 9 to 1; 9 = best quality, 6 acceptable, and 1 = poorest quality. Winter damage is based on a percent scale; 100$ = total kill and 0 = no damage 17 Fine Fescue Cultivar Trial K. L. Diesburg and N. E. Christians This trial was established during fall 1982. The purpose is to identify regional adaptation of the 32 cultivars and blends tested. Cultivars are evaluated each month of the growing season for turf quality and disease infestation. The average yearly performance of a cultivar is most important. 2 The trial is maintained with 4 lb. N/1000 ft through the growing season with irrigation as needed. A standard, single application of broad-leaf herbicide in September is used to prevent weeds. Preemergence herbicides were not used because of potential damage to the sensitive fine fescues during establishment. The entire area is maintained at a 2-inch mowing height. A combination of poor stand establishment with several cultivars and the lack of preemergence weed control resulted in weed infestation during July and August, the ratings of which are presented in Table 6. A disease epidemic which existed in the experiment through July and August lowered the quality ratings of some cultivars while others were unaffected (Table 6). All cultivars were recovering in October. Identification of the causal organism was not confirmed, but disease symptoms indicated Pythium sp. Four of the best cultivars in July (Waldina, NK79189, NK80346, and Wintergreen) were observed to perform poorly in October. In contrast, five cultivars (Aurora, Jamestown, Ensylva, Banner, and Agram) performed well regardless of disease and weather. As indicated by the similarity of experiment means at the bottom of Table 6, average performance of cultivars was generally stable through the growing season. Table 6. Turf quality,a disease,13 and weed0 ratings of fine fescue cultivars and blends . 0 Disease Cultivar 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. b c ^ f ® Banner-Checker HS Aurora Jamestown C Ensylva CR Dawson. CR FOF-WC S Banner C Scaldis-Atlanta Agram C C Kokét Fortress CR Barfalla C Atlanta C Shadow C Checker C Biljart H Dawson-Pennlawn Waldina H Ruby CR Highlight C H Scaldis CR NK79191 CR NK79189 NK80346 CR Pennlawn CR NK79190 CR CR NK80345 Wintergreen C NK80346 CR NK80348 CR Tournament H Duar H Exp. Mean LSD July 6.3 8.3 7.7 7.0 8.7 6.0 7.3 6.7 7.0 6.3 5.3 6.7 7.0 6.3 7.3 7.7 5.7 7.0 5.0 6.3 6.0 4.3 7.0 7.0 4.3 5.7 6.0 7.0 5.7 5.3 5.0 1.7 6.3 1.8 Turf Quality Aug Sept Oct 8.3 7.7 8.3 7.3 7.0 7.7 7.3 6.7 7.0 8.3 7.0 6.3 6.3 6.7 6.0 5.7 6.7 7.3 7.0 6.0 6.3 6.7 5.7 5.3 6.3 6.7 6.3 5.0 5.3 5.0 4.0 5.3 6.5 1.7 8.7 7.0 6.7 7.0 6.0 7.3 6.7 7.3 6.3 5.3 7.0 6.0 6.0 5.3 5.7 5.3 6.0 4.7 5.3 5.3 4.7 5.3 5.0 5.0 5.3 4.3 4.3 4.3 4.0 3.3 4.0 3.3 5.5 2.4 7.7 7.0 7.0 7.7 7.3 7.7 7.3 7.3 7.3 6.7 7.0 7.3 6.7 7.3 6.0 6.0 6.3 5.3 6.3 5.3 5.7 6.3 5.0 5.3 6.3 5.3 5.0 4.7 4.7 4.7 4.0 3.3 6.2 2.2 Weeds*" Mean^ (July) (Aug) 7.8 7.5 7.4 7.3 7.3 7.2 7.2 7.0 6.9 6.7 6.6 6.6 6.5 6.4 6.3 6.2 6.2 6.1 5.9 5.8 5.7 5.7 5.7 5.7 5.6 5.5 5.4 5.3 4.9 4.6 4.3 3.3 6.1 1.5 8.7 4.7 4.0 6.0 8.3 7.0 6.3 7.0 6.7 6.0 7.3 6.7 6.0 6.7 5.7 5.3 8.0 3.0 6.3 6.0 3.7 7.7 6.7 7.7 7.0 6.3 8.3 5.0 6.7 8.0 7.0 3.0 6.3 2.7 7.7 5.7 5.3 5.7 6.7 6.0 7.0 6.3 6.0 5.3 6.3 5.7 5.0 5.0 4.7 5.3 5.7 3.7 5.0 4.7 4.0 5.7 5.0 5.3 4.7 4.7 5.3 3.7 *t.3 5.0 3.3 3.3 5.2 2.5 quality rated on a scale of 1 to 9; 9 = best quality and 1 = poorest quality. disease rated on a scale of 1 to 9; 9 = no disease and 1 = most disease, weeds rated on a scale of 1 to 9; 9 = no weeds and 1 = most weeds. average of monthly quality ratings reflecting, but not including, disease ratings. disease symptoms typical of Pythium sp., but the causal organism was not confirmed. amount of weeds is a result of stand density during establishemnt. hard (H), chewings (C), sheep (S), or creeping red (CR) fescue, bluish-green color. 19 Kentucky Bluegrass and Perennial Ryegrass Management Studies Nick Christians The Kentucky bluegrass and Perennial Ryegrass management studies were established on August 16, 1979. The studies, which each include 10 cultivars, are divided into irrigated and nonirrigated sections. Each cultivar is maintained at two mowing heights* 1 and 2 inches, and is fertilized with IBDU at two rates, 1 and 3 lb. N/1000 ft /year. The Kentucky bluegrass cultivars were quite uniform in quality under irrigated conditions. Majestic received the highest overall quality rating in the irrigated plots when values were averaged over all mowing heights, fertility levels, replications, and months (Table 7). Under nonirrigated conditions, only Majestic received an acceptable quality rating. All of the perennial ryegrasses, with the exception of Caravelle and Linn, received acceptable quality ratings under irrigated conditions in 1983 (Table 8). Loretta, Yorktown, and Pennfine received the highest ratings in irrigated plots. Under nonirrigated conditions, there were no cultivars which received acceptable ratings for the entire season (Table 8). Caravelle received the highest rating in this part of the investigation. 20 Table 7. Species 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. (Cultivars) Merion Park Aquila Glade Baron Victa Sydsport Touchdown Majestic Adelphi Table 8. Species 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Quality ratings for ten Kentucky bluegrass cultivars maintained under nonirrigated and irrigated conditions. Nonirrigated Irrigated 4.9 5.2 5.4 5.4 4.5 5.4 4.9 6.0 4.9 4.9 6.6 6.3 6.3 6.5 6.0 6.5 6.3 6.4 6.9 6.1 Quality ratings for ten perennial reygrass cultivars maintained under irrigated and nonirrigated conditions. (Cultivars) Manhattan Pennfine NK 200 Derby Citation Diplomat Yorktown Caravelle Linn Loretta 21 Nonirrigated Irrigated 5.4 5.3 4.6 5.6 4.8 5.3 5.8 4.8 4.0 5.6 6.8 7.0 6.1 6.4 6.4 6.6 7.1 5.6 4.4 7.2 Fine Fescue Management Study Nick Christians The fine fescue management study includes the following cultivars: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Pennlawn Red Fescue Scaldis Hard Fescue Ruby Red Fescue Atlanta Chewings Fescue K5-29 Red Fescue Dawson Red Fescue Reliant (FL-1) Hard Fescue Ensylva Red Fescue Highlight Chewings Fescue Jamestown Chewings Fescue Each cultivar is maintained at two mowing heights: 1 and 2 inches. E^ch plot is also divided into two fertilizer treatments: 1 and 3 lb. N/1000 ft , applied as IBDU. The study was established on September 8, 1979, and is irrigated as needed. The quality ratings in Table 9 are the means of monthly observations taken from May to October ^veraged over both mowing heights. Cultivar plots treated with 3 lb. N/1000 ft /year were^observed to have higher quality ratings than those receiving 1 lb. N/1000 ft /year. Scaldis, Atlanta, Reliant, Jamestown, Pennlawn, and Dawson were the best cultivars at the higher fertility level. Scaldis, Atlanta, Reliant, and Jamestown also performed satisfactorily when maintained with 1 lb. N/1000 ft /year. Pennlawn and Dawson, although satisfactory at 3 lb. N, were not acceptable at 1 lb. N. Of the three species in the study, the hard fescues — Reliant and Scaldis — were the best performers overall. These two grasses performed much better than the others included in the test, particularly at the 1 lb. N rate. 22 Table 9. Species The effect of N fertilizer rate on the quality of ten fine fescue cultivars. N Fertilizer Rate 1 3 (Cultivar) 1. Pennlawn Red Fescue 5.3* 6.3 2. Scaldis Hard Fescue 7.4 8.4 3. Ruby Red Fescue 4.0 4.8 4. Atlanta Chewings Fescue 6.3 7.1 5. K5-29 Red Fescue 4.0 4.5 6. Dawson Red Fescue 5.6 6.6 7. FL-1 Hard Fescue (Reliant) 7.5 8.5 8. Ensylva Red Fescue 4.6 5.6 9. Highlight Chewings Fescue 4.9 5.1 10. Jamestown Chewings Fescue 7.2 7.6 LSD 0.05 to separate cultivars within a fertilizer rate = 1.0 . LSD 0.05 to separate differences among fertilizer rates within a cultivar = 0.15* values are the means of monthly observations from May through October. 23 Tall Fescue Management Study K. L. Diesburg and N. E. Christians The tall fescue management study includes Kentucky-31 and four new improved cultivars of tall fescue; Falcon, Houndog, Mustang, and Rebel. It was established in September, 1982. Stands were severely damaged by late spring freezing in 1983, and the plots were overseeded. Each cultivar is maintained at 2 and 3-inch Rowing heights and is fertilized with urea at 0, 1, and 2 Ib./N/1000 ft /year. Fertilizer treatments could not be imposed until September, 1983, when 1 lb. N/1000 ft was applied to the 2-lb. N level plots. In October, another 1 pound was applied to both 1 and 2-lb. N level plots. The data in Table 10 show that the addition of only 1 lb. N in September improved the average performance of all cultivars from an unacceptable (5.2 and 5.5) to acceptable (7.2) level. The difference in quality was due mainly to improved color where N was applied. In October, the plots treated with N showed less disease symptoms. There was no difference in response to mowing height managements, even though mowing treatments had been imposed since June. There were no differences in performance among the four improved cultivars averaged over all managements and treatments (Table 11). They all produced better quality turf than that of Kentucky 31, however. The difference was due to finer texture and darker color of the improved cultivars. 24 Table 10. Means of turf quality ratings at three fertility levels cultivars tested. Applied N g over all Sept Oct Avg (lb./1000 ft2 ) 1. 0 5.2 3.6 5.1 2. 1 5.5 5.5 5.6 3. 2 7.2 6.3 6.2 0.4 0.3 0.1 LSD 0.05 g Equal amounts of N were applied to levels 2 and 3 during October. additional pound was applied to level 3 in September. An g Table 11. Means of turf quality ratings treatments. for tall fescue cultivars over all Cultivar July Aug Sept Oct Avg Falcon 5.7 6.8 6.2 5.2 6.0 Houndog 6.0 6.3 6.2 5.2 5.9 Kentucky 31 3.8 5.0 4.7 4.6 4.5 Mustang 5.5 6.5 6.4 5.3 5.9 Rebel 5.6 6.3 6.2 5.3 5.9 1.0 0.5 0.5 0.4 0.3 LSD 0.05 g ratings based on 9 = best, 1 = dead, andl 6 = acceptable turf. 25 Bentgrass Management Study Nick Christians The bentgrass management study was established in the fall of 1980. includes the following species and cultivars: Species It Cultivar 1. Agrostis stolonifera Emerald Creeping Bentgrass 2. Agrostis canina Kingstown Velvet Bentgrass 3. Agrostis stolonifera Penncross Creeping Bentgrass 4. Agrostis stolonifera Penneagle Creeping Bentgrass 5. Agrostis stolonifera Prominent Creeping Bentgrass 6. Agrostis stolonifera Seaside Creeping Bentgrass Each cultivar planting is split into three fertility levels: 0.5, 0.8, and 1.2 lbs. N/1000 sq. ft./growing month. This results in a total N application rate of 3.5, 5.6, and 8.4 lbs. N/1000 sq. ft./year. The area was manged as a golf course green, with a 3/32 inch mowing height and with applications of insecticides and fungicides as needed. Each cultivar is replicated four times. The summer of 1983 was unusually hot and there was a great deal of stress on the bentgrass study area. Under these conditons, Penncross maintained the best season long quality (Table 12). Emerald also maintained an acceptable season long quality. Penneagle, Kinstown, Prominent, and Seaside received unacceptable ratings for the season as a whole. During the high stress periods of July and August, only Penncross performed satisfactorily. Penncross was clearly the best cultivar for the high stress conditions in central Iowa in 1983. Quality ratings increased with increasing rates of N for each of the cultivars (Table 13). For Kingstown, Penneagle, and Prominent there was no advantage to increasing N from 0.8 to 1.2 lb. N/month. For Emerald, Penncross, and Seaside, the highest quality was observed at 1.2 lb. N/month. This is a very high level of N and it is surprising that these cultivars did not deteriorate in quality at this rate during high stress periods. 26 Table 12. The 1983 quality ratings for six bentgrass cultivars with data averaged over four replications and three fertility levels . Cultivar May June July Aug Sept Oct MEAN 1. Penncross 6.2 7.6 6.8 7.1 7.0 6.4 6.8 2. Emerald 6.2 5.9 5.9 5.7 5.8 6.4 6.0 3. Penneagle 6.0 6.0 6.3 5.0 4.3 6.7 5.7 4. Kingstown 5.8 4.9 5.5 5.3 5.8 6.0 5.5 5. Prominent 5.9 5.3 5.3 5.4 4.9 6.3 5.5 6. Seaside 5.6 5.3 5.6 5.7 4.6 5.6 5.4 0.9 0.9 1.0 1.4 1.4 0.7 0.7 LSD 0.05 Quality is based on a scale of 9 to 1; 9 - best quality, 6 = acceptable, and 1 : lowest quality. Table 13. The effects of fertility level on the quality of six bentgrass cultivars. lb. N/growing month Cultivar 0.5 0.8 1.2 1. Emerald 5.5 5.9 6.5 2. Kingstown 5.1 5.8 5.7 3. Penncross 6.1 6.9 7.5 4. Penneagle 5.5 5.7 5.9 5. Prominent 4.9 5.9 5.9 6. Seaside 4.8 5.3 6.1 LSD 0.05 for comparison of fertility levels within cultivar = 0.5. 27 Evaluation of Different N Sources, Rates, and Timings for Fertilization of Kentucky Bluegrass Turf Norman Hummel In this study five nitrogen sources are being evaluated at different rates and timing for maintenance fertilization of Kentucky bluegrass turf. The turf is Enmundi Kentucky bluegrass which was established in August 1981 and is maintained at a cutting height of 2 inches. All clippings are removed. A randomized complete block design with three replications is being used. Plot size is 4 x 6 feet. The treatments include four slow release N sources applied at 2, 3, and 4 lb N/1000 sq ft/year. The treatments are applied in one, or split into two applications. Urea was applied at 2, 3, and 4 lb N/1000 sq ft/year split into four equal applications. The dates of fertilizer applications in 1983 were May 20 and September 24 for all treatments. The urea treatments were also applied on July 7 and November 15. To assess turf quality, visual ratings of color were made approximately every two weeks. Ratings were made on a scale of 0 to 5, using half units, with 5 indicating dark green. Ratings less than 3*0 were considered unacceptable quality. A value of 0 would indicate a yellow or straw-colored appearance. Results The color ratings are shown in Table 14. are not significantly different. Means followed by the same letter The highest color ratings prior?to spring fertilization were the Andersons SCU 1 + 3 (1 lb N/1000 in spring, 3 lb N in fall)* the IBDU treatments in which 2 or 3 lb N was applied per 1000 ft^ previous fall. Good color was also produced by the Lakeshore SCU 2. The poorest color was found on all ureaform plots, and on all receiving less than 1.5 lb N/1000 ft the previous fall. produced by followed by in the 1 + 3 and 2 + plots The quickest response to fertilization, as reflected in color ratings, was produced by the Andersons SCU at the 2 and 3 lb rates, followed closely by the Lakeshore SCU at the same rates. Acceptable color was also produced by all the IBDU treatments four and six weeks after fertilization. Poor color ratings were obtained on all ureaform plots for most of the season. Even the 3 lb rate in spring failed to produce acceptable color during the summer. Only the 1 lb rate of urea produced acceptable color after spring fertilization. The other two urea rates (0.5 and 0.75 N/1000 sq ft) simply did not provide sufficient available nitrogen to maintain quality turf. This may be of special interest to lawn care companies using urea as the primary N source in their program. Where clippings are removed from the turf area, 1 lb N/1000 sq 28 ft appears to be the minimum needed in the spring to produce the desired quality. Later in the summer and fall, the lower rates of N from urea did produce acceptable color. The most uniform response to fertilization was produced by the Lakeshore SCU 2 + 2 and the Andersons SCU 2 + 2 . Excellent performance was also observed for the Lakeshore SCU 1 + 3 * The heavy fall fertilization provided excellent residual N the following spring, and through the following summer. The Lakeshore SCU 3 + 1 provided sufficient N to maintain good color through the summer, but did not have enough residual N to hasten spring green-up. A quicker release rate was evident with the Andersons SCU. Both the 3 + 1 and 1 + 3 treatments produced excellent color following fertilization, but there was not sufficient residual N to maintain acceptable color through the season. It appears that where clippings are removed, a minimum annual rate of 3 to 4 lb N/1000 sq ft is necessary to maintain high quality bluegrass turf in Iowa. Of course, N requirements will vary with cultivar, management, and the individual's perception of quality. 29 Table 14. Effect of nitrogen source, rate and timing of application on quality of Enmundi Kentucky bluegrass turf a m \C No. Kate 4/ 2 0 Date 5/20 Color Rating 5/4 6/27 6/9 ^ 7 / l r> 7/29 Date 9/9 Color Rating 8/19 9/24 10/14 b 11/ 5 1 0 4 2 l .8 h -j 2.3 f-l 2. 8 c - f 2.3 J-1 2.3 1-1 2 . 2 kl 2.5 i -1 2.3 f-l 2.3 b-e 2.3 c-e 3.0 c -g 3.0 c - f •> 1 4 1 1 . 3 1-1 2 . 0 »»-j 2. 0 R-) 3.0 3.5 b-e 3.2 f-h 2. 7 f - i 2.3 f-l 2.0 d - f 2. 8 a-d 2.5 2.0 i-.l 2 4 0 1 . 7 1- k 2.3 f-i 2.3 e - i 3 . 5 c. -e 3.5 b-e 3.3 e - g 3.3 d-g 3.0 c-e 3 . 0 ab 3.0 a-c 2.0 i - k 1.5 l - n 4 1. 5 4 1.5 2.0 f - i 2.3 f-i 2.8 c - f 3.3 d - f 3.3 c - f 3. 3 e - g 3.5 d - f 3.0 c-e 2.5 a-e 2. 8 a-d 2.8 d-h 2.5 5 1 4 2 2.5 d -g 3 .0 b-e 3.2 2.8 g - i 3.3 c - f 3.2 3.5 d - f 2.8 c - f 2.7 a-d 3.0 a-c 2.8 d-h 3.3 b-d 6 2 4 l 2.0 f - i 2.5 e-h 2.8 c - f 3.7 b-d 3.7 a-d 3. 7 c - e 3.7 c -e 3.0 c-e 2.7 a-d 2.7 a-d 2.5 f-j 2.7 e-h 7 2 + 2 2.7 3 .0 b-e 3 .7 ab 4 . 0 ab 4 . 0 ab 4 . 3 ab 4.5 a 3 . 7 ab 3 . 0 ab 3.3 a 3.7 a - c 3 . 3 b-d 8 1 4 3 3 .0 b-d 3 . 3 be 3.5 a - c 3.7 3.8 a-c 4 . 0 be 3 . 8 b- d 3.3 a -c 2.8 a -c 3 . 2 ab 3.3 a -e 3 . 7 ab 9 3 4* ! 2.3 e-h 2.8 c - f 3.2 b- d 4 . 0 ab 4 . 0 ab 4.5 a 4.5 a 3.8 a 3.2 a 3.3 a 2.7 e - i 2.7 e-h 1. 8 i - k 2. 2 c - f 2 . 2 de 3.7 a - c 3.5 a - c f-i 2.2 c - f 2.7 a-d 2. 8 d-h 2.5 c-f b-e f-h b- d f-h f-j f-i 10 0 4 2 2.7 3 . 3 be 3 .0 b-e 2.2 kl 2 . 0 k-m 2 . 2 kl 2 . 2 k-m 11 1 4 1 2.3 e-h 2.3 2.7 d-g 3.0 f-h 2.8 f - i 2.8 h - j 2.7 1? 2 4 0 1.0 l 1.3 k 1.5 j 3.8 a-c 3.5 b-e 3. 7 c - e 3.8 b-d 3.0 c-e 2.3 b-e 2 . 2 de 1. 8 j k 1 . 3 mn 11 1 . 5 4 1. 5 2.7 3 .0 b-e 3 .0 b-e 3.3 d -f 3.3 c - f 3.3 e-g 2.8 g - j 2.3 f-i 1. 8 e f 2.3 c-e 3.2 b-f 3.2 b-e 14 1 4 2 3.2 a - c 3 . 5 ab 3.5 a - c 2.8 g - l 2.8 f - i 3.0 g-l 3.0 f - l 2.5 e-h 1. 8 e f 2.3 c-e 3.3 a-e 3.2 b-e 15 2 4 1 2. 7 c - f 2.8 c - f 3.2 3.8 a - c 3.5 b-e 3.5 d - f 3.5 d - f 3.0 c-e 2 .3 b-e 2.5 3.0 c -g 2.5 f-i 16 2 4 2 3.2 a - c 3 . 5 ab 3 . 7 ab 3.8 a - c 3.2 d-g 3. 7 c - e 4.2 a-c 3.2 2 .3 b-e 3 . 2 ab 3.7 a - c 3.7 ab 17 1 4 3 3.7 a 4.0 a 4.0 a 2.8 g - l 2.8 f - i 2.8 h - j 3.2 e-h 2.7 d -g 2.3 b-e 2.3 c-e 4.0 a 4.0 a 18 3 4 1 2. 8 b-e 3.3 3.5 a - c 4.2 a 4 . 0 ab 4 . 3 ab 4 . 3 ab 3.3 a - c 2.8 a-c 3.0 a-c 3.5 a-d 3.2 b-e 19 (1 4 2 1.0 1 1.5 j - k 1.7 2.0 1 1 . 8 lm 2 . 0 1m 2 . 2 k-m 2. 0 h-k 2.0 d -f 2.8 a-d 3.5 a-d 2 . 0 i -1 2.0 l-n 2.2 g - j 2.2 c - f 2.8 a-d 2.5 1 . 7 k-m c-f c-f f-i be b-d ij h-k 2.3 b-d b-e f-i 20 1 4 1 1.3 j -1 1.5 j k 1 .8 h - j 2. 2 k l 2 . 0 k-m 2 . 0 lm 21 2 4 0 1 . 3 j -1 1. 8 i - k 1. 8 h - j 2. 2 k l 2.5 h-k 2.5 jk 2 . 3 j -1 2.2 g - j 2.2 c - f 2.8 a-d 2.0 i - k 1.8 j-m 22 1 ..5 4 1 . 5 1. 2 k l 2.0 h-j 2.3 e - i 2.7 h-j 2.8 f - i 2.5 jk 2 . 2 k-m 2. 2 g - j 2. 2 c - f 2.3 c-e 2.7 e - i 2 . 0 i -1 2.3 f-j 21 1 4 2 1. 8 h - j 2.0 h -j 2.2 f - j 2.2 kl i-1 2 . 2 kl 2 . 2 k-m 2.3 f-i 2.7 a-d 3.0 a-c 3.7 a-c 3.0 c - f 24 2 4 1 J .3 J-1 1. 8 i - k 2.0 g - j 2.5 i-k 2.5 h-k 2. 7 i j 2 .7 h-k 2.3 f-i 2.5 a-e 2.5 b-e 2.7 e - i 1. 8 j-m 25 2 4 2 1. 7 1 - k 2.0 h-j 2.2 f - j 2.7 h-j 3.0 e-h 3.2 f-h 3.0 f - l 2.5 e-h 2.0 d - f 3.0 a-c 2. 8 d-h 2. 8 d-g 26 1 4 3 1 . 3 j -1 2.0 h-j 2.0 g -j 2.2 kl 2.5 h-k 2.7 ij 2.8 g - j 2.7 d-g 2 .3 b-e 3.0 a-c 3.3 a-e 3.2 b-e 27 3 4 1 1. 7 i - k 1. 8 i - k 2.2 M 2.8 g - l 2.5 h-k 2.8 h -j 3.3 d-g 3.0 c-e 2.2 c - f 2.7 a-d 2.8 d-h 2 . 0 i -1 28 0 4 2 2.2 f - i 2.5 e-h 2.5 d-h 2.0 1 2 . 0 k-m 1. 8 lm 1 . 7 mil 1.5 k 1.5 f 2 . 2 de 2.0 i - k 2. 8 d-g 29 1 4 l 2.5 d-g 2.3 f-i 2.2 f - j 2.0 1 2.3 i-1 2 . 0 lm 2 . 2 k —in 2.5 e-h 2.3 b-e 2.3 c-e 2.3 g - j 1. 8 j-m 30 2 4 0 1 . 3 j -1 1. 8 i - k 2. 0 fi-j 2.7 h-j 2.8 f - i 3.0 g - l 3.0 f - i 2.7 d-g 2.2 c - f 2 . 2 de 1. 8 j k 1 . 7 k-m 31 1 . 5 4 1. 5 2.8 b-e 3 .0 b-e 2.8 c - f 2.2 kl 3.0 e-h 3.0 g-l 3.0 f-i 2.7 d-g 2 .3 b-e 2 . 2 de 2.0 j - k 2.5 32 l 3.2 a-c 3.3 be 3.? i-k 3.0 e-h 3.0 g-l 2.8 g - j 2.5 e-h 2.2 c - f 2 . 2 de 1.5 k 2.7 e-h f-i 3.0 4 2 b-d 2.5 f-i 33 2 4 1 2.2 f - i 2.3 2.5 d-h 2 . 3 j -1 3.2 d-g 3.2 f-i 2.7 d -g 2.3 b-e 2.5 b-e 2.2 h-k 1. 8 j - m 34 2 4 3.2 a - c 3 . 3 be 3.5 a-c 2.7 h - j 3.5 b-e 3.3 e-g 3.3 d-g 2. 8 c - f 2.3 b-e 2.7 a-d 2.0 i - k 2.2 h-k 35 1 4 3 3 . 3 ab 3 .5 ab 3 . 7 ab 2.2 kl 3.0 e-h 3.2 3.3 d-g 2.7 d-g 2.0 d - f 2.3 c-e 2.2 h-k 3.2 b-e 36 3 4 1 3 . 0 b-d 3.2 b-d 3.5 a-c 2.7 4.2 a 3 . 8 cd 3.8 b- d 3.3 a-c 2. 8 a - c 2.8 a-d 2.5 f-j 1. 8 j-m 37 4 X 0 ,. 2.0 f - i 2.2 g - i 1. 8 h - j 2.2 kl 2 . 0 k-m 2.5 2.8 g - j 2.3 f-i 1. 8 e f 2 . 2 de 3.3 a-e 2.3 g-j 38 4 X 0 ,. 75 c-f 2.7 d-g 2.7 d -g 3.0 f-h 2 . 2 k-m 2.8 h - j 3.5 d - f 3.0 c-e 2.2 c - f 2 . 2 de 3 . 8 ab 3.2 b-e 19 4 X 1 2.8 b-e 3.2 3 .0 b-e 3.2 e - g 2.7 g - j 3.5 d - f 4 . 3 ab 3.2 2 .3 b-e 2.3 c - e 3.7 a- c 3.0 c - f 40 0 l .2 kl 1.3 k 1. 8 h - j 2.0 1 1.5 m J.7 m 1. 5 n 1 . 7 jk 1. 8 e f 1. 8 e 2.0 i - k 1.0 n 2 5 2.7 b- d h-j f-h f-h jk b-d aMeans followed by the same letter are not significantly different, ^First rating after fertilization. treatments 1-9, Lakeshore SCU, 37-0-0; treatments 10-18, Andersons SCU, 32-0-0; treatments 19-27, Ureaform, 38-0-0; treatments 28-36, IBDU, 31-0-0; treatments 37-39, urea, 46-0-0; treatment 40, check. 30 Plastic-Coated Urea as a Slow-Release Fertilizer for Kentucky Bluegrass Norman Hummel The objective of this study was to evaluate five plastic-coated urea (PCU) treatments for maintenance fertilization of Kentucky bluegrass turf. The turf is Enmundi Kentucky bluegrass which was established in August 1981, and is maintained at 2 inches in height. A randomized complete block design was used with three replications. Plot size was 4 x 6 feet. The treatments include four PCU materials with different release rates: 70, 100, 150, and 270 days. A fifth treatment was a mixture of equal proportions (25^) of the four PCU materials. Lakeshore (LS) SCU and Canadian Industries Ltd. (CIL) SCU were included for comparison. All materials were applied at a rate of 4 lb N/1000 sq ft/year in either single spring or split applications. The spring treatments were applied May 20, 1983 and the fall treatments were applied September 24, 1983. Fresh weight yields were taken twice monthly except (September and October) to evaluate response to the different treatments. To determine fresh weight yields, clippings were collected from 1.6 square meters, which represents one pass over the length of the plot with a 21-inch rotary mower. To assess turf quality, visual color ratings were made twice monthly. Ratings were made on a scale of 0 to 5, using half units, with 5 indicating dark green. Ratings of less than 3-0 were considered unacceptable color. Results Fresh-weight yields and color ratings are shown in Tables 15 and 16, respectively. Means were compared using the Waller-Duncan LSD test, allowing comparisons within each column. Means followed by the same letter are not significantly different. The highest yields and dark color were produced by the PC-70 4 + 0 and the CIL SCU 4 + 0 following spring fertilization. High yields were also produced by the single spring application of LS SCU and PC-mixed. The most uniform response to fertilization was produced by the PC-270 4 + 0. Dark color and moderate yields were produced throughout the season. Acceptable color was maintained until November. Uniform response was also obtained from the single spring application of LS SCU and PC-mixed; however, the LS SCU produced very high yields after fertilization which would require more frequent mowing (Table 15). While the performance of the PC-270 was impressive at the high spring rate, there was insufficient available N at the 2 lb rate to maintain acceptable color for very long. The PC-70 and PC-100 performed very well when the total N was split into two applications. The performance of the treatments could have improved even more had the fall treatments been applied 3 weeks sooner. 31 Table 1 5 Effect of various fertilizer treatments on fresh-weight yields of Kentucky bluegrass turf. »0 c (U H X Q) "d NO CN M-I OO cn IM CO X d e* QJ XJ m XJ e* cj XJ u r-> XJ o e- XJ 1 X CM X CM co CM CM CM CM X OO m XJ 1 X e- d o XJ 1 X XJ 1 X e~ X) o CM x CM . QJ 1 Xl CO XJ l d e* X) l d e- CJ 1 d X X d o X) 1 d X X d o QJ 1 CJ X d X CJ l X X Ip o vO cn co co CM CO co co X CU d CO CO •H u u 'd cu •H o O rH rH .. LO o o o o o o LO o u VO 00 00 oo 00 00 oo o o> • d o •H rH rH CU cu < u Q) 4-4 cd u O rH co g 4-> CU d 4-1 o r\ o> LO o m LO in LO o o 00 o- 00 o* O' 00 rH u o !—1 o o CO CU cu •rH B T3 U cd 00 O' O' 00 O' O' o U o 1—1 rd a u cd TJ II £ o 1—1 CO rH u o O' o\ •H rH o O' O' u O o o o> o> oo o. o o o I— 1 *d d cd >> d l o •H 4-» cd i-i "d cu cu o i—i rH CU LO LO LO O' o- o LO o LO O' O' o < rH o d cd rH O o CO •H *d i—i u o o o o § e 4-» d d cu a) II u 00 OV 00 CM cd cu u H o vO io ,•— N o in o o LO vO vO LO vO LO LO o cu u cd *d u C U rd £ l O' i—i I 1 Ov MH O CM vO o o LO O' O' O'. LO o LO O' O' LO O' LO o C U i—1 cd a CO cu u 0 <3 co • CM . vO vO o LO . ON . CM vO <3• 00 rH 04 Cu •H i— 1 U 00 o 00 vO vO CO <3- o . CM . vO vO vO r>- co co co o 00 oo 00 00 00 o • 00 CO o . o . co ON on <3" CO oo 00 I— 1 o vO vO ON 00 O • X) G cd T3 cd (D "O II cd 0 ex 4J OO 3 H <3 . 00 • 00 CO CD rO II ON >n rH ►O 4-) £ CD 0 CM 4-J M -4 C) c) c) r—1 CO on oo oo CO co 00 00 vO 00 cd CD CO u X1 i— \ 1— 1 C o T3 LO rQ o CD CO cd LO CM • 00 a cd c) 4-1 H o and 4 oz/A and split rates of .25 + .25, .50 + .50, 1 + 1 , 2 + 2 , and 3 + 3 oz/A. Each treatment was applied in 326 ml. of water at 20 psi with a hand held boom operated in four differing directions to ensure uniform coverage. The 326 ml. of water per plot is equivalent to 150 gallons of water per acre. The single application rates were applied July 11, 1983, and the second application of the split rates were applied July 25, 1983. 52 Kentucky bluegrass was maintained at a height of 2" while tall fescue was cut at 3". Atj quarterly intervals throughout the growing season, 1 lb. N (SCU)/1000 ft was applied to the studies. Water was applied by the sprinkler irrigation system as needed to prevent moisture stress. Data taken weekly during the study included fresh clipping weights and quality ratings. The quality ratings were determined on a scale from 9 to 1, 9 = best quality and 1 = dead turf. The same treatments were applied to the second study later in the Fall (October 1 and 15) . Data will be taken in Spring 1984. Results and Discussion The responses varied with species and treatment rates. The Kentucky bluegrass showed a much higher tolerance to the chemical with no decrease in quality at the highest single and split application rates. However, as the chlorsulfuron rate increased the clipping weight decreased (Table 3 D « This observation suggests that chlorsulfuron has some growth retarding effects on Kentucky bluegrass. Chlorsulfuron is systemic and is active through the foliage and root system. Death of tall fescue plants is slow and is accompanied by chlorosis, necrosis, terminal bud death, vein discoloration and complete growth inhibition. The tall fescue showed a very low tolerance to the chemical and was severely effected at single rates of 2 oz/A and split rates of 2 + 2 oz/A and greater. Injury occurred at the lower rates, however, the tall fescue recovered from damage at 1 oz/A single rate and the 1 + 1 oz/A split rate. The data from this study indicates that chlorsulfuron has the potential for being a selective control for tall fescue in Kentucky bluegrass. 53 Table 31. Quality and clipping weight data for single and split applications of chlorsulfuron. SINGLE APPLICATIONS CLIPPING WEIGHT - GRAMS QUALITY TREATMENT - OZ/A K.B. T.F. K.B. T.F. Control 8 9 1-+.7 5 2 .7 .25 8 9 1 7 .0 43.1 .5 0 8 8 .3 14.0 4 4 .0 1 8 3 .7 8 .3 3 2 .3 2 8 4 .7 1 0 .3 5 .3 3 8 4 5 .3 5 .3 4 8 2 .3 r-> ry ( ( 0 .0 • SPLIT APPLICATIONS 1 CLIPPING WEIGHT - GRAMS QUALITY TREATMENT - OZ/A K.3. T.F. K.B. r.n•r £t* .2 5 + .2.5 8 os 1 0 .3 3 8 .3 •5 + .5 8 8 .3 1 + i 8 8 1 2 .0 2 1 .3 2 + 2 8 .3 3 .7 7 .3 2 .3 3 + 3 3 1.7 n f 0.0 * K.3. = Kentucky Bluegrass, T.F. = Tall Fescue 54 Q *'f7 ' 4»ni 3 9 .0 TALL FESCUE CONTROL STUDY - 1983 CHLORSULFURON TREATMENTS - OZ/A Control 8. .2 5 • 50 1 .0 2 .0 3.0 ^.0 7 1 B :F .2 5 4 .2 5 .5 0 4 .5 0 1 .0 4 1 .0 2 .0 4 2 .0 3 .0 4 3 .0 9. 10. 11. 12. 2 5 1 i 1 F 'B B ‘F 3 F 3 k b ;f f 8 10 l 1 12 6 11 9 B !F i B 1F B lF { 6 3 1 3 'F F 'B __ 1__ (split rates at 2 week interval) F 1 B B« __ 1__ 1 f j "Tall Fescue Alleys" 10 1 2 25' F ' B i B.F 2 1 11 i i I i 1 B 'F B'F F'B B 1F BF 1 8 b ; f 8 9 11 1 1 l F.B B«F 1 i I > i 7 3 9 i i B ,F F'B F B 2 F 1 60' B Bluegrass, F = Fescue 55 5 k 1 i F ■ B F'B B -F t 1 1 I 5 i 1 B B 1F J 7 F *B i F'B 12 10 6 £ i i i B ,F __ 1__ B 'F I F ,B B jF k 1983 Growth Retardant Study Nick Christians The objectives of this investigation were to evaluate the effectiveness of Monsanto 4621 flowable and Monsanto 4623 2G as growth retardants of Kentucky bluegrass, to compare the effects of the recommended rate of these materials (2.5 lb ai/A) to double applications (2.5 + 2.5 lb ai/A), and to compare the Monsanto materials to other growth retarding compounds. Monsanto 4621 4 flowable (2.5 and 2.5 + 2.5 lb ai/A), Monsanto 4623 2G (2.5 and 2.5 + 2.5 lb ai/A), Mefluidide (0.38, 0.38 + 0.38, and 0.25 lb ai/A), EL-500 (0.75 and 1.00 lb ai/A), and Ethephon (3.5 and 5.0 lb ai/A) were applied to 5' x 5* plots on a 2 year old stand of Enmundi Kentucky bluegrass on April 29, 1983. All liquid materials were applied with a C0„ backpack sprayer designed for 5' plots. The Mon 4623 2G was applied with a hand held shaker. Each of the double application treatments were applied first at the recommended rate, then immediately reapplied at that same rate. This was done to simulate overlaps during application. The materials were allowed to remain on the tissue for 24 hours and were then irrigated in with approximately water. This was followed by 2.32” of rain by May 3. One week following treatment, all plots were mowed at a 2" mowing height. Data collection began one week after that mowing and continued for six weeks. Weekly data were collected on quality, both before and after mowing, on fresh weight of clippings, and on height of growth above the 2" mowing height. One half of each plot remained unmowed throughout the study. The height of growth measurements were taken from the top of the 2" mowing height to the top of the unmowed area. Seed head counts were made on this unmowed area four weeks after treatment. Results The Mon 4621 (2.5 and 2.5 + 2.5 lb ai/A), Mon 4623 (2.5 and 2.5 + 2.5 lb ai/A), and the mefluidide (0.38 + 0.38 lb ai/A) were the most effective growth retarding treatments (Table 32). The mefluidide (0.38 lb ai/A) treatment reduced growth— averaged over six weeks— in comparison with the control, but was not as effective as the single applications of the Mon 4621 and 4623 materials. The double applications of Mon 4621 and Mon 4623 reduced growth over the six week period as compared to single applications; however, these reductions were not statistically lower. EL-500 (0.75 and 1.00 lb ai/A) reduced growth as compared to the control, but was not as effective as the Mon 4621, Mon 4623, or the double application of mefluidide. The ethephon was not effective in reducing growth. This was surprising, because of the effectiveness of this material in previous studies. The lack of effectiveness in this test may have been due to the unusually high rainfall which occurred during the investigation. The clipping yield data followed similar trends to the height of growth data (Table 33). Again, the Mon 4621, Mon 4623, and mefluidide were effective in reducing growth. The EL-500 (1.00 lb ai/A) was also quite effective. The Mon 4621 and Mon 4623 reduced clipping yield effectively for the first six weeks. In the 7th and 8th weeks, there was a rapid increase in growth at all rates of these two materials. This increase was nearly double the control in week 8. The mefluidide also showed a large increase in clipping yield in weeks 7 and 8. The EL-500 (0.75 and 1.00 lb ai/A) was still effective in growth reduction in the 6th week of data collection (eight weeks after treatment). 56 Quality ratings prior to mowing were generally lower than those made just after mowing (Tables 34 and 35). This is likely due to the fact that non­ uniformity enters into evaluations performed prior to mowing. Evaluations made after mowing are based primarily on color and density. The mefluidide treatments were generally unacceptable in quality prior to mowing for the first four weeks of data collection (Table 34). The mefluidide (0.38 + 0.38) was in some cases higher than single application rates due to the improved seed head inhibition at the double rate (Table 36). The Mon 4621 and 4623 were acceptable in pre-mowing quality throughout the study. All treatments were judged to be acceptable in quality after mowing at all dates (Table 35). The ethephon maintained an exceptionally good color and density at each testing week. Only the Mon 4623 (2.5 + 2.5 lb ai/A) had a lower quality than the control when means of the six weeks of data collection were compared. No treatments were totally effective in reducing seed head development (Table 36). The plots with the fewest seed heads were those treated with Mon 4621 (2.5 + 2.5 lb ai/A). The Mon 4621 (2.5 and 2.5 + 2.5 lb ai/A), Mon 4623 (2.5 and 2.5 + 2.5 lb ai/A), and mefluidide (0.38 and 0.38 + 0.38 lb ai/A) treatments were effective in reducing seed head numbers as compared to the control. The El-500, ethephon, and mefluidide (0.25 lb ai/A) were not effective. Considering all measured variables, the Mon 4621 and Mon 4623 were the most effective growth retardants in this study. There appeared to be no serious detrimental effects from applying double applications of these materials to the same plot. It should be noted that this study was conducted during an unusually wet spring. During a more normal period, better results would have been expected from the mefluidide and ethephon. The fact that the Mon 4621 and 4623 maintained effectiveness under these wet conditions may indicate that they would be preferable to other materials in more humid regions. 57 Table 32. Growth above the 2" mowing height over a six week application. Treatment lb ai/A Week 3**Week 4 period following Week 5 Week 6 Week 7 Week 8 Mean 1. Control — 1.8* 2.8 3.4 4.2 6.3 9.8 4.7 2. Mon 4621 4 fio 2.50 0.9 1.1 1.2 1.8 3.8 4.5 2.2 3. Mon 4621 4 fio 0.9 0.7 0.9 1.4 2.8 4.1 1.8 4. Mon 4623 2 G 0.8 1.1 1.7 1.7 3.2 4.1 2.1 5. Mon 4623 2 G 2.5 + 2.5 0.7 0.7 0.8 1.2 2.5 4.5 1.7 6. Mefluidide 0.38 1.3 1.7 1.7 3.0 5.5 7.5 3.5 7. Mefluidide 0.38 + 0.38 0.9 1.2 1.2 1.8 2.8 4.9 2.1 8. Mefluidide 0.25 1.7 2.0 2.1 3.1 5.8 9.8 4.1 9. EL-500 0.75 1.7 2.5 2.8 2.9 3.7 7.1 3.4 10. EL-500 1.00 1.6 2.2 2.5 2.8 3.8 5.8 3.1 11. Ethephon 3.50 2.0 2.6 3.0 4.2 5.8 9.1 4.4 12. Ethephon 5.00 2.0 2.8 3.0 3.7 6.6 9.2 4.5 LSD 0.05 — 2.1 0.7 1.1 1.0 1.6 2.2 0.8 2.5 + 2.5 2.50 * data are the difference between the two inch mowing 1deight and the unmowed section of the plot. ** data collection began at the beginning of the third week after treatment. 58 Table 33. Clipping weights in pounds per 1000 sq ft produced over a six week period following application. Treatment lb ai/A Week 3 Week 4 Week 5 — 1 . Week 6 Week 7 Week 8 Mean lbs— 20.5* 32.1 14.5 5.9 13.5 11.8 16.4 2.0 6.0 2.5 1.9 12.7 20.3 7.6 1.2 5.3 1.8 1.8 10.7 21.5 7.0 4.3 6.0 2.5 2.3 12.3 24.5 8.6 2.5 + 2.5 1.5 8.2 9.7 4.3 10.5 22.0 9.4 0.38 6.7 12.8 6.8 5.7 9.6 22.5 10.7 2.4 5.7 4.1 3.5 13.1 26.5 9.2 Control 2. Mon 4621 4 flo 3- Mon 4621 4 flo 4. Mon 4623 2 G 5. Mon 4623 2 G 6. Mefluidide 7. Mefluidide 0.38 + 0.38 8. Mefluidide 0.25 10.3 14.9 10.5 6.7 14.5 22.1 13.2 9. EL-500 0.75 18.8 25.5 7.4 3.6 15.3 6.4 12.8 10. EL-500 1.00 14.3 19.5 6.2 2.2 4.4 4.4 8.5 11. Ethephon 3.50 23.2 30.8 12.7 5.0 9.2 9.4 15.0 12. Ethephon 5.00 25.2 31.8 10.6 4.6 12.0 10.7 15.8 LSD 0.05 — 5.9 7.3 7.1 2.8 N.S. 4.5 3.3 * 2.50 2.5 + 2.5 2.50 plots were mowed at a 2" mowing height. 59 Table 34. Weekly quality ratings taken just prior to mowing. Treatment lb ai/A Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Mean 1. Control — 8.0» 8.5 9.0 9.0 8.5 7.5 8.5 2. Mon 4621 4 flo 2.50 6.5 7.5 6.5 7.5 7.5 8.0 7.0 3. Mon 4621 4 flo 6.5 7.0 6.5 7.0 8.0 7.5 7.0 4. Mon 4623 2 G 7.0 6.5 5.5 6.5 7.5 8.0 7.0 5. Mon 4623 2 G 6.5 7.5 6.5 6.5 8.0 8.0 7.0 6. Mefluidide 5.5 5.0 5.0 5.5 8.0 7.5 6.0 7. Mefluidide 0.38 + 0.38 6.5 6.5 5.5 7.0 8.5 8.0 7.0 8. Mefluidide 0.25 5.0 5.5 5.5 6.5 8.0 8.0 6.5 9. EL-500 0.75 8.0 8.5 9.0 7.5 7.5 6.5 8.0 • o 1 —1 EL-500 1.00 8.0 8.5 8.5 7.5 7.0 6.5 8.0 11. Ethephon 3.50 8.0 8.5 8.5 8.5 7.5 7.5 8.0 12. Ethephon 5.00 8.0 8.0 8.5 8.0 8.0 7.5 8.0 LSD 0.05 — 0.8 0.8 1.1 1.0 N.S. N.S. 0.5 2.5 + 2.5 2.50 2.5 + 2.5 0.38 * quality rating on a scale of 9 to 1; 9 = best quality, lowest quality. 60 6,= acceptable, and 1 = Table 35. Weekly quality ratings taken after weekly mowing. Treatment lb ai/A Week 6 Week 7 Week 8 Mean Week 3 Week 4 Week 5 8.5* 9.0 8.5 8.0 7.5 7.5 8.0 1. Control 2. Mon 4621 4 flo 2.50 7.5 8.0 7.0 7.5 8.5 7.5 7.5 3. Mon 4621 4 flo 2.5 + 2.5 7.0 8.0 7.0 7.5 7.5 7.5 7.5 4. Mon 4623 2 G 7.0 7.5 6.5 7.5 8.0 8.0 7.5 5. Mon 4623 2 G 6.5 8.0 6.5 7.5 7.0 8.0 7.0 6. Mefluidide 0.38 6.5 7.5 6.5 7.5 8.5 7.5 7.5 7. Mefluidide 0.38 + 0.38 7.0 7.5 6.5 7.5 8.0 8.0 7.5 8. Mefluidide 0.25 7.0 7.5 7.0 7.5 7.5 8.0 7.5 9. EL-500 0.75 8.5 9.0 9.0 8.0 6.5 6.5 8.0 10. EL-500 1.00 8.5 8.5 8.5 8.0 6.0 6.5 7.5 11. Ethephon 3.50 8.5 9.0 8.5 8.5 8.0 8.0 8.5 12. Ethephon 5.00 8.5 8.5 8.5 8.0 8.0 7.5 8.5 LSD 0.05 — 0.6 0.7 0.8 N.S. 0.7 N.S. 0.5 2.50 2.5 + 2.5 * quality rating on a scale of 9 to 1; 9 = best quality, lowest quality. 61 6 = acceptable, and 1 = Table 36. The number of seed heads per square foot of plot area. Treatment Seed heads/sq ft lb ai/A 1. Control — 2. Mon 4621 4 flo 2.50 3. Mon 4621 4 flo 4. Mon 4623 2G 5. Mon 4623 2G 6. Mefluidide 7. Mefluidide 0.38 + 0.38 8. Mefluidide 0.25 171 9- EL-500 0.75 167 10. EL-500 1.00 193 11. Ethephon 3.50 193 12. Ethephon 5.00 181 202 64 2.5 + 2.5 19 74 2.50 2.5 + 2.5 36 0.38 88 29 LSD 0.05 60 62 ’ The Effects of Monsanto 4623 2G on Six Cultivars of Tall Fescue Nick Christians The objective of this investigation was to evaluate the effects of Mon 4623 2G on six cultivars of tall fescue. On May 2, 1983, Mon 4623 2G (2.5 lb ai/A) was applied to Kenhy, Falcon, Rebel, Kentucky-31, Belt TF-11, and T.F. 14801 tall fescue (Festuca arundlnacea Schreb.). The cultivars chosen for this study were established in 1979 in three replications in plots measuring 4' x 6'. The Mon 4623 was randomly applied to one half of each cultivar plot in each replication with a hand held shaker. The plots were mowed once per week in such a way that one half of the treated and one half of the untreated area were mowed at 3" and one half of each area remained unmowed. Data collected included measurements of growth between the unmowed control and the unmowed treated area, measurements of growth between the unmowed treated area and the 3" mowing height, quality ratings on the unmowed treated area, quality rating on the treated area just after mowing, and percent seed head inhibition. Results The effects of the treatments were very slow to develop. It was not until the 3rd week after treatment that data collection began. The efficacy of the material was also quite short, with no apparent differences between treated and untreated areas by the 6th week after treatment. The growth of Kenhy was inhibited to a lesser extent than any of the other cultivars (Table 37). The T.F. 14801 (an experimental from North American Plant Breeders) was inhibited more than Kenhy but less than Falcon, Rebel, and Kentucky-31. There were no differences in quality rating for any of the cultivars. of the cultivars were unacceptable in quality on unmowed areas and were generally acceptable after mowing (Table 38). Many Percent seed head inhibition varied numerically, but there were no significant differences (Table 39). The response of Falcon, Rebel, and Kentucky-31 to Mon 4623 were fairly uniform, although there was a small difference in growth between Falcon and Rebel (Table 37). There are cultivars of tall fescue, such as Kenhy, which may respond differently to Mon 4623 than do the more commonly used cultivars. It should be noted that these are the results of only one limited field study. If these potential differences in response pose a serious problem in marketing of the product, more detailed greenhouse studies should be conducted. 63 Table 37. The effect of Mon 4623 (2.5 lb ai/A) on six cultivars of tall fescue. Unmowed treatedmowed treated** Control-unmowed treated* Cultivar Week 3 Week 4 Week 5 Mean Week 3 Week 4 Week 5 Mean — inches---1. 2. 3. 4. 5. 6. Kenhy Falcon Rebel Kentucky-31 Belt TF-11 T.F. 14801 0.8 1.1 1.3 1.6 1.1 1.2 1.2 2.6 2.8 5.3 3.9 2.6 0.6 4.2 5.1 5.5 4.2 2.5 0.9 2.6 3.1 4.1 3.1 2.1 1.2 0.7 0.5 0.6 0.8 0.5 3.7 2.5 2.1 1.8 2.1 3.3 9.8 5.6 4.3 6.1 7.0 7.2 4.9 2.9 2.3 2.8 3-3 3.7 LSD 0.05 N.S. 2.4 N.S. 1.5 N.S. N.S. 3.0 0.5 * Measurement of the difference between unmowed control and unmowed treated area . ** Measurement of the difference between the unmowed treated and the 3” mowing height of the treated area. Table 38. Quality ratings taken just after mowing and quality ratings taken on unmowed areas. Quality Rating After Mowing Cultivar 1. 2. 3. 4. 5. 6. Kenhy Falcon Rebel Kentucky-31 Belt TF-11 T.F. 14801 Week 3 Week 4 Quality Rating of Unmowed Area Week 5 Week 3 Week 4 Week 5 6.0 6.5 6.0 5.5 6.5 6.0 6.5 6.5 6.5 5.5 7.0 6.5 8.0 8.0 8.0 8.0 8.0 8.0 5.0 5.5 5.5 5.0 5.5 5.5 5.0 5.5 5.5 4.5 5.5 5.5 8.0 7.5 7.5 7.0 6.5 8.0 N.S. N.S. N.S. N.S. N.S. N.S. Quality rating on a scale of 9 to 1; 9 = best quality, 6 = acceptable, ; 1 = lowest quality. 64 Table 39. Seed head inhibition of 6 tall fescue cultivars by Mon 4623 (2.5 lb ai/A). Cultivars 1. 2. 3. 4. 5. 6. Kenhy Falcon Rebel Kentucky-31 Belt TF-11 TF 14801 % Seed head control* 15 45 30 30 45 33 N.S * 100/6 control = no seed heads and 0 = no difference between treated and control. Effects of Six Growth Retardants on the Vegetative Growth of Kentucky Bluegrass 1983 Kenneth L. Diesburg and Nick Christians INTRODUCTION A field experiment was conducted to compare the effects of Ethrel, EL500, Embark, PP-333, Monsanto 4621, and Monsanto 4623 on leaf and stem growth of Baron Kentucky bluegrass at three different seasonal stages of growth. MATERIALS AND METHODS Application dates May 5, June 23, and September 24, represented spring reproductive, summer, and fall vegetative stages, respectively. Chemicals were applied at recommended rates to 5' x 5' plots. Liquid solutions were dispersed through a hand-held boom with three spaced nozzles passing three feet above the ground with pressurized COp in a tank strapped to the operator's back. Granular Mon 4623 was broadcast by hand. A split-plot design was used, with application dates as whole-plots and chemicals as sub-plots in three replications. The grass was mowed immediately prior to application and once more one week afterward. Canopy height was measured from the soil surface three times per plot on a given date,then averaged. Leaf length, leaf number, and internode number were measured and counted from nine representative shoots per plot on the same date and then averaged. Subjective ratings of toxicity were based on turf color with 9 = green and 1 = brown. Ratings of heading were also subjective with 1 = most heading and 9 = no heads. RESULTS Canopy Height. All of the chemically treated plots showed lower canopy heights than that of the control. Ethrel and Embark were, generally, more effective than EL500, PP-333> Mon 4621, and Mon 4623 (Tables 40 and 41). The effectiveness of EL500 was not different from that of PP-333, Mon 4621, or Mon 4623. Embark's advantage was negated by its phytotoxicity (Table 42). Response to Ethrel was not evident until more than two weeks after application (Tables 40 and 41). In fall, EL500 was more effective than Ethrel within the first two weeks, less effective from two to four weeks, and equally effective beyond four weeks. In summer, however, Ethrel was consistently better than EL500 in restricting increase in canopy height. Toxicity. Ethrel, EL500, and PP-333 caused little or no browning of turfgrass leaves. Mon 4621 and Mon 4623 produced more evidence of toxicity and Embark severely damaged the leaves (Table 42). Heading. Embark, Mon 4621, and Mon 4623 were very effective in preventing heading while Ethrel, EL500, and PP-333 were ineffective (Table 40). Although the differences in heading among EL500, PP-333, and the control were within the 66 limits of variability, the heading in response to EL500 and PP-333 seemed to be greater than that of the control. Leaf Length and Number. The data in Tables 43, 44, and 45 were taken after the summer treatments had been applied on June 23. Initial plant response to the chemicals was generally slow with the exception of Ethrel and Embark (Table 43). The effect of Embark was obvious in that plant growth was immediately arrested and existing leaves were damaged. The initial effect of Ethrel was more subtle. Leaves continued to elongate as with the other four chemicals and control, but the frequency in which a leaf was missing at the third, fourth, and fifth leaf positions was markedly reduced. It appeared that the senescence of older leaves was being greatly delayed. Leaf senescence in response to the other four chemicals was similar to that of the control. Optimal effects of all chemicals could be seen within 28 days after application (Table 44). The inhibition of new leaf growth relative to the control can be seen in the low values in average leaf length at leaf one. Differences in average leaf length at leaves four and five are due mainly to differences in leaf senescence since those leaves were present before applying the chemicals. (Bear in mind that mean leaf length at leaves three, four, and five is affected by the number of leaves absent at those positions among the nine shoots sampled. Each leaf absent caused a zero to be entered into the corresponding Length mean.) With Ethrel, EL500, PP-333, Mon 4621, and Mon 4623 the accumulated Length over all five leaves was not drastically reduced, rather leaves one and two were significantly shorter than those of the control while leaves three, four, and five were similar to or longer than those of the control. This redistribution of leaf area caused a lower canopy, thereby postponing the need for mowing. Ethrel caused a much more dense canopy than that of any other chemical or the control. It changed plant morphology from that of two to four leaves per shoot with leaf two being much longer than the others, to that of three to six leaves per shoot with quite uniform leaf length. Leaf density and color were not objectional for any chemical except Embark. Plots sprayed with Embark had a brown thin canopy as a result of shoot death, leaf senescence, and strong inhibition of growth. Inhibition of leaf elongation at leaves one or two was still evident with Ethrel, Embark, and EL500 more than a month after application (Table 45). Plants treated with PP-333, Mon 4621, and Mon 4623 had completely recovered. Shoot Elongation. Ethrel stimulated an elongation of internodes in shoot stems that was not observed with any other chemical or the control (Table 46). Interactions. In affecting canopy height, the interaction of chemicals with times of application was significant at all time periods of sampling after the application dates. This indicates that some chemicals performed better in one season versus another. For instance, EL500 exerted stronger restriction of growth relative to the other chemicals after fall application versus summer application. The performance of Ethrel, on the other hand, was the reverse. 67 DISCUSSION The results among chemicals after each seasonal application were much different. Air temperatures during and after the spring application were quite cool (40-50 F), and plants were not growing vigorously. During and after summer applications, however, air temperatures ranged from 65-90 F. Soil temperatures were probably equally divergent. Although air temperatures were moderate during and after the fall application (50-70 F), the plants had previously shifted growth phases from that of upright, rapid leaf growth to prostrate, slow leaf growth in the beginnings of preparation for winter. The significant chemicalby-application time interactions indicate the sensitivity of all the chemicals to a combination of environment and growth phase of the turfgrass. An effect peculiar to Ethrel was the elongation of internodes in shoots. This phenomenon is normally seen only in reproductive shoots. The effect on turf quality could be either negative or positive. Canopy height is raised, but shoot density might be improved if extended nodes root into the soil. SUMMARY Embark quickly stopped all plant growth, but severely damaged the turf. Ethrel was the most effective inhibitor of leaf elongation and subsequent increase in canopy height without damaging turf color. EL500, PP-333, Mon 4621, and Mon 4623 inhibited growth to lesser extents. The EL500 and PP-333 caused no decrease in turf color ratings while Mon 4621 and Mon 4623 caused slight damage. Embark, Mon 4621, and Mon 4623 effectively inhibited heading while Ethrel, EL500, and PP-333 were ineffective. 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