1992 Iowa Turfgrass Research Report IOWA SIATE FG-459 IJune 1992 Introduction N. E. Christians and M. L. Agnew The following research report is the 12th yearly publication of the results of turfgrass research projects performed at Iowa State University. Copies of information in earlier reports are available from most of the county extension offices in Iowa. The 1991 season was an establishment year for several new trials that were established in 1990. Among the new trials established in the fall of 1990 were a low-maintenance Kentucky bluegrass trial, a high-maintenance Kentucky bluegrass trial, a perennial ryegrass trial, a green-height creeping bentgrass trial, and a creeping bentgrass green for fungicide trials. For the second year, this research report contains a section titled "Environmental Research." This section is included to inform the public of our many research projects that are aimed at the many environmental issues that face the turf industry. In the past two years this has become a major thrust of the research program and many of our more extensive, in-depth projects are now aimed at environmental issues. We would like to acknowledge Richard Moore, manager of the turfgrass research area; Mark Stoskopf, superintendent of the ISU Horticulture Research Station; Sue (Kassmeyer) Berkenbosch, technical assistant; Doug Campbell, technical assistant, and all others employed at the field research area in the past year for their efforts in building the turf program. Special thanks to Barb Erickson for her work in typing and helping to edit this publication. Edited by Nick Christians, professor, Horticulture; and Michael Agnew, associate professor, Horticulture. Table of Contents Turfgrass Research Area Maps Environmental Data 1 4 Species and Cultivar Trials Results of Kentucky Bluegrass Regional Cultivar Trials - 1991 6 The Recovery of Kentucky Bluegrass Cultivais Following Summer Dormancy 16 National Perennial Ryegrass Study 19 Regional Fine Fescue Cultivar Evaluation 24 Tall Fescue Cultivar Trial 28 Shade Adaptation Study - 1991 31 USGA Buffalograss Trial - 1991 33 Green Height Bentgrass Cultivar Trial (Native Soil) 34 Fairway Height Bentgrass Study - 1991 36 Fairway Height Kentucky Bluegrass Trial - 1991 37 Herbicide Studies Preemergence Annual Weed Control Study - 1991 40 Postemergence Broadleaf Weed Control Study - 1991 43 Effects of Dithiopyr (Dimension) on the Rooting of Creeping Bentgrass 46 1991 Sod Rooting Trial - I 48 1991 Sod Rooting Trial - II 53 The Effect of Prograss on the Establishment of Cool-Season Grasses 55 The Efficacy of Ignite (HOE-39866) as a Non-selective Herbicide 57 The Effects of Quinclorac on the Establishment of Three Grass Species 59 Fairway Height Bentgrass Response to Postemergence Herbicides 62 Turfgrass Disease Research The Response of Kentucky Bluegrass Turf to Mefluidide Applied in Combination with Fungicides and Other Compounds 64 Evaluation of Fungicides for Control of Dollar Spot on 'Emerald' Bentgrass - 1991 66 Evaluation of Fungicides for Control of Brown Patch in Creeping Bentgrass - 1991 70 Evaluation of Fungicides for Control of Snow Molds on Creeping Bentgrass, 1990-1991 74 Evaluation of Rubigan-Cutless Combinations for Control of Dollar Spot in Creeping Bentgrass - 1991 76 Stress Studies and Fertilizer Trials Natural Organic Trial 78 The Effects of Granular Nitrogen Fertilizer Sources on the Growth and Quality of 'Park' Kentucky Bluegrass 83 The Evaluation of Nitrogen Sources on the Quality of Bentgrass Greens 88 The Effects of Synthetic and Natural Organic Nitrogen Source and Core Cultivation on Turfgrass Growth under Traffic Stress 90 MURP Studies 95 Plant and Soil Response to Nitrogen Fertilizer Sources 98 1991 Comparison of Kentucky Bluegrass Response to ONCE and Methylene Urea 106 1991 Soil Activator Study 110 Micronutrient Study on Putting Greens 113 Clipping Reduction of Kentucky Bluegrass with Growth Regulators 119 Environmental Research Pesticide and Fertilizer Fate in Turfgrasses Managed under Golf Course Conditions 123 Drift of Postemergence Herbicide Spray during a Turfgrass Application 127 Isolation and Identification of Allelopathic Compounds from Wet Milling Com By-products 130 Ground Ivy Control with Borax 131 Organic Lawn Care Trial 133 Introducing The Iowa State University Personnel affiliated with the Turfgrass Research Program 134 Companies and Organizations that made donations or supplied products to the Iowa State University Turfgrass Research Program 136 Wlldflower Nativa Crasa Establishment Study Common KBG Vantage KBG Parade KBG Sod Rooting Study Park KBG Ram I KBG ¿3 SB'S National Kentucky Bluegrass Trial Reliant Fine Fescue Twilight Tall Fescue Baron (Ron-Irrigated) Perennial Ryegrass Cultivar Study Kentucky Bluegrass Cultivar Study Endophyte Study ■pa o •5 D K Fallow Argyle Alternative Craas Trials Buffalograss Management Study Nassau KBG Texolca Ram I Common Fairway Height Kentucky Bluegrass Study Sharps Glade K.B.G. CO P 3CO txo p a Turfgrass Research 261,360 ft2 6.0 Acres I8 ££ 8b lU l0Q Argyle Tall Fescue Kentucky Bluegrass Seed Mixtures Prograss Study 'i*2 Sa* ?* 3d PremiumSod Blend S. D. Certified tè % Fairway Height Creeping Bentgrasa Trial Fine Fescue Cultivar Study Rebel II Study Seed Priming Study Sod Rooting Inhibition Study Topdressing Study Premium Sod Blend Emerald Green Height Creeping Bentgrasa Fungicide Trials Trial Fertilizer Trial FertilizerTrial Emerald Pennero* SR 1020 Granular Fertilizer Study t ^BuildinJ N Ornamental Grass Trial -1- FertilizerCultiration Study 1984 Expansion of the Turfgrass Research Area 108,900 ft2 - 2.5 Acres (640 series heads) Manhattan P. Rye Envy P. Rye V an tage M ajestic V an tage Majestic Park "ilffW Ug" Demo Liquid VtrtU zttion Study P ark V an tage P ark Majestic Premium Sod Blend USGA Bentgrass Green (S 600 series heads) 35’ Park 65 60 •a o „ Micronutrient •äfS Dollar Spot aU o°° Study m 130* £3 & Fairway Ht. Fert. Study Ram 1 Midnight ESI 180' Tall Fescue Compaction Study (690 series heads) (650 series heads) O tx "I Glade Fertilizer Study 180' ’ E a s t R e s e a r c h A rea 165 P^O H Suipjmg aoirsuaiupsyj; -3- S3H3NI -4- 01APR 01 MAY 01JUN DATE, 1991 01JUL 01 AUG DAILY RAINFALL 01 SEP 010C T uaHNasHVi -5- Solid Line = Max Dashed Line = Min DAILY TEMPERATURE - AMES Results of Kentucky Bluegrass Regional Cultivar Trials - 1991 N. E. Christians and R. J. Moore The United States Department of Agriculture (USDA) has initiated several regional Kentucky bluegrass cultivar trials that are currently being conducted at most of the northern agricultural experiment stations. The test consists of 62, 80, or 128 cultivars; the number depending on the year of establishment and the type of trial, with each cultivar replicated three times. Three trials were underway at Iowa State University during the 1991 season. A highmaintenance study was established in 1990 that receives 4 lb N/1000 ft2/yr and is irrigated as needed. The second trial was established in 1985 and receives 4 lb N/1000 ft2/yr, but is not irrigated. The third trial was established in the fall of 1990 and is a low-maintenance study that receives 1 lb of N/1000 ft2/yr in September and is not irrigated. The objective of the high-maintenance study is to investigate the performance of the 128 cultivars under a cultural regime similar to that used on irrigated home lawns in Iowa. The objective of the second study is to observe the response of 80 cultivars under conditions similar to those found in non-irrigated lawns that receive a standard lawn care program. The objective of the third study is to evaluate 62 cultivars under conditions similar to those maintained in a park or school ground. The values listed under each month in Tables 1,2, and 3 are three replicated plots for the three studies. Yearly means of data from each month were taken and are listed in the last column. The first cultivar received the highest average rating for the entire 1991 season. The cultivars are listed in descending order of average quality. -6- Table 1. The 1991 quality ratings for the high-maintenance irrigated Kentucky bluegrass test that was established in the fall of 1990. Cultivar May June July Aug Sept Oct Mean 1 Ram 1 7.3 8.0 8.0 7.7 8.0 7.7 7.8 2 Conni 6.7 8.0 8.0 7.7 8.0 7.0 7.6 3 HV 125 7.0 7.3 8.0 7.3 8.0 8.0 7.6 4 PST-0514 7.3 7.7 7.7 7.3 7.7 8.0 7.6 5 Able 1 7.3 7.7 7.7 6.7 7.7 8.0 7.5 6 Crest 7.0 7.0 8.0 7.0 8.0 7.7 7.4 7 Indigo 7.0 7.7 7.7 7.3 7.7 7.0 7.4 8 PST-UD-10 7.0 7.3 7.7 7.0 7.7 8.0 7.4 9 Blacksburg 8.0 7.7 6.3 7.0 7.7 8.0 7.4 10 Glade 7.0 7.7 7.0 7.3 7.7 7.7 7.4 11 BA 77-279 7.3 7.3 7.3 6.3 7.7 7.7 7.3 12 BA 77-700 7.0 7.0 7.7 6.7 8.0 7.3 7.3 13 Fortuna 6.7 7.0 7.7 7.0 8.0 7.3 7.3 14 PST-HV-116 6.8 7.0 7.0 7.3 8.0 7.8 7.3 15 PST-HV-928 6.7 7.0 7.7 7.3 7.7 7.3 7.3 16 Nustar 6.7 7.0 7.7 7.3 7.7 7.3 7.3 17 Dawn 6.7 7.0 7.7 7.0 8.0 7.7 7.3 18 SR 2100 6.3 7.3 7.7 7.0 7.7 7.7 7.3 19 Baron 6.7 7.0 7.3 6.7 8.0 7.3 7.2 20 BAR VB 895 6.3 7.3 7.3 7.0 7.7 7.7 7.2 21 Touchdown 6.0 7.0 7.3 7.3 7.7 7.7 7.2 22 WW AG 508 6.7 7.0 7.0 7.0 7.7 7.7 7.2 23 BA 73-366 6.3 7.0 7.3 7.3 8.0 7.0 7.2 24 NE 80-47 7.0 6.7 7.3 7.0 8.0 7.3 7.2 25 Cynthia 6.0 7.3 7.7 7.3 8.0 6.7 7.2 26 602 6.7 7.3 7.7 6.7 8.0 7.0 7.2 27 PST-A7-341 6.7 7.3 7.3 6.7 7.3 7.7 7.2 28 Kelly 7.0 7.0 7.7 7.3 7.3 6.7 7.2 29 ST 2000 7.0 7.3 7.0 6.7 7.7 7.7 7.2 30 Fylking 4.7 6.7 7.7 8.0 8.0 8.0 7.2 -7- Cultivar May June July Aug Sept Oct Mean 31 Trampas 6.0 7.0 7.7 7.0 8.0 7.0 7.1 32 BA 69-82 6.3 7.3 7.3 6.0 8.0 7.3 7.1 33 Ampellia 6.7 7.0 7.0 7.0 8.0 7.0 7.1 34 Miracle 6.7 6.7 7.3 6.7 7.3 8.0 7.1 35 EVB 13.863 6.3 7.0 7.3 7.3 7.7 7.0 7.1 36 Washington 6.3 7.0 7.7 7.3 7.3 7.0 7.1 37 BAR VB 7037 6.0 7.3 7.3 7.0 8.0 6.7 7.1 38 1757 6.0 7.3 7.3 6.3 7.7 7.7 7.1 39 PST-A84-405 6.7 7.0 7.0 6.7 7.7 7.7 7.1 40 PST-A84-803 6.3 6.7 7.3 6.3 8.0 8.0 7.1 41 R751A 6.7 6.7 7.3 7.0 7.7 7.3 7.1 42 Midnight 6.3 7.7 6.7 6.7 7.7 7.7 7.1 43 PR-1 5.7 6.7 7.3 6.7 8.0 8.0 7.1 44 PSU-151 6.3 7.0 7.7 7.0 7.7 7.0 7.1 45 J13-152 6.0 6.3 7.7 7.0 8.0 7.3 7.1 46 Aspen 6.7 7.0 7.7 6.0 7.7 7.7 7.1 47 Trenton 6.0 7.0 7.3 7.3 8.0 7.0 7.1 48 Opal 6.3 7.3 7.7 6.7 7.7 6.7 7.1 49 Estate 6.3 7.3 6.7 6.7 7.3 7.7 7.0 50 H86-712 6.3 7.3 7.0 6.0 7.3 8.0 7.0 51 BA 73-382 6.3 6.7 7.0 6.7 7.7 7.7 7.0 52 BA 76-305 6.3 7.0 7.0 7.3 7.7 6.7 7.0 53 WW AG 505 7.0 7.0 6.7 6.3 7.7 7.3 7.0 54 Melba 6.0 7.0 7.3 6.7 8.0 7.0 7.0 55 Livingston 6.7 6.3 7.3 6.7 8.0 7.0 7.0 56 PST-1DW 5.5 7.5 7.0 7.0 8.0 7.0 7.0 57 Summit 5.0 7.0 7.3 7.0 8.0 7.7 7.0 58 Liberty 5.3 7.3 7.3 6.7 7.7 7.7 7.0 59 Jll-94 6.0 6.3 7.0 7.3 7.7 7.7 7.0 60 Cobalt 7.0 6.3 7.0 6.3 7.3 8.0 7.0 61 Classic 6.0 6.3 7.3 7.0 7.7 7.3 6.9 62 Merit 7.3 6.7 7.0 6.0 7.3 7.3 6.9 -8 - Cultivar May June July Aug Sept Oct Mean 63 Alpine 6.0 6.7 7.0 7.3 8.0 6.7 6.9 64 BA 73-540 5.3 7.3 7.3 6.0 8.0 7.3 6.9 65 BA 73-381 6.3 6.7 7.0 6.7 7.3 7.3 6.9 66 BA 78-258 6.7 6.3 7.0 6.7 7.7 7.3 6.9 67 Abbey 6.7 7.0 7.7 6.3 7.3 6.3 6.9 68 EVB 13.703 5.7 7.0 7.0 6.3 7.7 7.7 6.9 69 PST-A7-341 6.0 7.0 6.7 6.7 7.7 7.7 6.9 70 PST-R-740 6.0 6.7 7.3 6.7 7.7 7.0 6.9 71 Nassau 6.0 7.0 7.0 6.3 7.3 7.7 6.9 72 J34-99 6.0 6.7 6.7 7.0 7.7 7.7 6.9 73 Freedom 5.7 6.0 7.0 7.3 8.0 7.7 6.9 74 Limousine 6.3 7.7 6.7 6.3 7.7 6.7 6.9 75 J-386 6.7 6.7 6.7 6.3 8.0 7.0 6.9 76 J-229 5.3 6.7 7.7 7.0 7.3 7.3 6.9 77 Chelsea 7.0 7.0 7.0 6.7 7.3 6.3 6.9 78 A-34 6.0 6.7 6.7 6.7 8.0 7.0 6.8 79 Marquis 6.7 6.3 6.7 6.3 8.0 7.0 6.8 80 Barzan 5.0 7.0 6.7 7.3 7.3 7.7 6.8 81 BA 70-131 5.3 6.7 7.3 6.0 7.7 7.7 6.8 82 Prince 104 6.7 7.0 6.3 5.7 8.0 7.3 6.8 83 PST-RE-88 5.7 6.7 7.0 6.7 7.3 7.7 6.8 84 PST-C-76 7.0 6.7 7.0 6.0 7.0 7.3 6.8 85 PST-UD-12 6.3 6.3 7.0 6.0 7.7 7.3 6.8 86 PST-B8-106 6.0 6.7 6.7 6.3 8.0 7.0 6.8 87 Suffolk 6.0 6.3 7.0 6.7 7.7 7.0 6.8 88 J-333 6.0 7.0 7.3 7.0 7.3 6.3 6.8 89 Minstrel 6.7 7.3 7.0 6.0 7.0 6.7 6.8 90 Gnome 6.3 7.0 6.7 6.3 7.3 7.0 6.8 91 Ronde 5.7 6.0 8.0 7.0 7.7 6.3 6.8 92 Cheri 5.3 7.3 6.7 6.3 7.7 7.3 6.8 93 Platini 6.0 7.3 6.3 6.3 7.3 6.7 6.7 94 Miranda 7.3 6.7 6.3 6.0 6.7 7.0 6.7 -9 - Cultivar May June July Aug Sept Oct Mean 95 Silvia 6.3 6.3 7.0 6.0 7.7 7.0 6.7 96 Eagleton 6.3 6.0 7.0 6.0 7.3 7.3 6.7 97 PST-C-224 6.0 6.7 7.0 5.7 8.0 7.0 6.7 98 Destiny 6.7 6.7 6.0 5.7 7.3 8.0 6.7 99 Eclipse 6.7 6.3 6.3 6.3 7.7 7.0 6.7 100 Haga 6.0 6.7 6.7 6.0 7.7 7.0 6.7 101 Banff 6.0 6.0 7.0 6.3 7.3 6.7 6.6 102 BA 77-292 6.3 6.0 7.0 6.7 7.3 6.3 6.6 103 Georgetown 5.7 6.3 7.0 6.0 7.7 7.0 6.6 104 Challenger 5.0 6.3 6.3 6.0 7.7 8.0 6.6 105 South Dakota Cert. 5.7 5.3 7.0 6.7 7.7 7.0 6.6 106 Monopoly 6.0 6.0 6.7 6.7 6.7 7.0 6.5 107 BAR VB 1169 5.3 6.7 6.3 6.7 7.3 6.7 6.5 108 BAR VB 1184 4.3 6.0 6.3 6.7 8.0 7.7 6.5 109 798 4.7 6.3 6.7 6.0 7.7 7.7 6.5 110 Barblue 5.7 6.0 6.3 5.7 7.0 7.7 6.4 111 Barmax 6.0 6.3 6.0 6.0 7.0 7.3 6.4 112 BA 74-114 7.3 6.3 6.0 5.0 6.3 7.3 6.4 113 PST-B8-13 5.3 6.0 6.7 6.7 7.7 6.0 6.4 114 Julia 5.0 6.3 7.0 6.0 7.3 7.0 6.4 115 J-335 5.3 6.0 7.0 6.3 7.3 6.7 6.4 116 KWS PP 13-2 6.7 6.7 6.3 6.3 6.7 6.0 6.4 117 Kenblue 6.0 5.3 7.3 6.7 7.0 6.0 6.4 118 Donna 5.3 6.3 6.0 6.0 7.3 7.0 6.3 119 Greenley 5.7 5.3 7.0 6.7 7.0 6.0 6.3 120 Coventry 5.0 6.0 6.0 5.7 7.3 7.3 6.2 121 Ginger 5.7 5.3 6.7 6.3 7.0 6.3 6.2 122 Gemor 6.0 5.0 6.0 6.3 7.3 6.7 6.2 123 Noblesse 6.0 6.3 5.7 5.7 6.3 6.3 6.1 124 Barsweet 5.7 6.3 5.3 5.3 7.0 6.0 5.9 125 Bartitia 4.0 5.0 6.0 6.3 7.3 7.0 5.9 126 Cardiff 4.3 5.7 6.0 6.7 6.3 6.7 5.9 - 1 0- Cultivar May June July Aug Sept Oct Mean 127 Broadway 4.7 6.3 5.3 5.3 6.7 6.0 5.7 128 Merion 4.3 6.0 5.3 4.3 5.7 5.0 5.1 LSD,a05) 1.3 1.3 1.1 1.2 0.9 0.9 0.7 Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. Table 2. The 1991 quality ratings for the high-maintenance, non-irrigated regional Kentucky bluegrass test that was established in the fall of 1985. Cultivar May June Aug Sept Oct Mean 1 Joy 6.0 6.3 4.3 4.3 5.3 5.3 2 South Dakota Cert. 5.7 6.7 4.7 4.7 5.0 5.3 3 Kenblue 6.3 6.3 4.0 4.3 5.0 5.2 4 Huntsville 5.7 6.0 3.3 4.0 5.3 4.9 5 J-1872 6.0 6.7 3.0 3.7 5.3 4.9 6 Monopoly 5.3 6.0 3.7 3.7 5.0 4.7 7 Lofts 1757 5.0 6.0 3.3 4.3 5.0 4.7 8 Wabash 6.0 5.3 3.3 4.3 4.7 4.7 9 Harmony 4.7 5.7 4.0 4.3 5.0 4.7 10 NE 80-14 5.7 5.0 4.0 3.7 5.0 4.7 11 Somerset 4.7 5.7 3.3 4.7 4.7 4.6 12 Aquila 6.0 6.0 2.3 3.3 5.3 4.6 13 Able I 4.7 5.7 3.7 4.0 4.3 4.5 14 Park 4.7 5.3 3.7 3.7 5.0 4.5 15 Rugby 4.7 5.3 3.7 3.0 5.3 4.4 16 Baron 4.7 4.7 4.0 3.3 4.3 4.2 17 Aspen 5.7 5.0 3.0 3.0 4.2 4.2 18 PST-CB1 4.3 5.7 2.7 3.7 4.7 4.2 19 Classic 4.7 5.7 3.0 3.0 4.3 4.1 20 Tendos 5.3 6.3 2.7 2.7 3.7 4.1 21 Georgetown 3.7 5.7 3.0 4.0 4.3 4.1 22 Eclipse 4.7 6.0 2.7 2.7 4.7 4.1 23 Dawn 5.3 5.7 2.0 3.0 4.3 4.1 Cultivar May June Aug Sept Oct Mean 24 239 4.0 5.7 3.0 3.3 4.3 4.1 25 K3-178 4.0 5.7 3.0 3.7 4.0 4.1 26 NE 80-110 5.0 6.0 3.0 2.3 4.0 4.1 27 A-34 3.3 5.0 3.7 3.7 4.3 4.0 28 Julia 4.0 4.3 2.7 4.7 4.3 4.0 29 Trenton 3.3 5.0 3.7 3.3 4.7 4.0 30 WW AG 496 4.0 5.3 2.7 4.0 4.0 4.0 31 Victa 4.7 5.7 2.7 2.3 4.0 3.9 32 BA 70-242 5.0 4.7 3.3 2.7 4.0 3.9 33 NE 80-88 4.0 4.7 3.0 4.0 4.0 3.9 34 America 3.0 4.0 3.7 4.7 4.0 3.9 35 Liberty 4.0 5.0 3.7 3.0 4.0 3.9 36 Nassau 4.3 5.3 3.0 3.0 3.7 3.9 37 Ikone 3.7 5.0 2.7 4.0 4.3 3.9 38 WW AG 495 3.7 5.0 2.7 3.3 4.7 3.9 39 Mystic 3.3 5.0 3.7 4.0 3.0 3.8 40 Parade 4.3 5.0 2.0 3.3 4.3 3.8 41 Welcome 4.7 5.0 2.3 3.0 4.0 3.8 42 WW AG 468 4.7 5.7 3.0 2.3 3.3 3.8 43 WW AG 491 4.0 6.0 2.0 3.0 4.0 3.8 44 Merit 4.3 5.0 2.7 2.7 4.0 3.7 45 Bristol 3.7 4.7 3.0 3.0 4.3 3.7 46 BA 72-441 4.3 5.3 3.0 2.3 3.3 3.7 47 BA 73-626 4.3 5.0 3.0 3.0 3.3 3.7 48 Destiny 5.0 4.7 2.7 2.3 4.0 3.7 49 Glade 4.0 5.0 2.7 3.0 4.0 3.7 50 NE 80-50 4.0 4.7 2.3 3.0 4.7 3.7 51 Gnome 3.7 4.0 3.0 3.0 4.3 3.6 52 P-104 3.7 4.3 2.7 3.7 3.7 3.6 53 BAR VB 577 3.7 5.0 2.0 3.3 4.0 3.6 54 BAR VB 534 4.3 5.0 2.3 2.7 3.7 3.6 55 Cynthia 4.3 4.3 2.7 2.7 4.0 3.6 Cultivar May June Aug Sept Oct Mean 56 Merion 4.7 5.0 2.3 2.3 3.7 3.6 57 Kl-152 4.0 5.3 2.3 2.7 3.7 3.6 58 NE 80-47 4.0 4.7 2.0 3.3 4.0 3.6 59 NE 80-48 4.0 5.3 2.3 2.3 4.0 3.6 60 Ram I 3.3 5.0 3.0 2.7 3.7 3.5 61 Haga 4.0 5.0 2.3 2.7 3.3 3.5 62 Annika 3.3 5.3 2.3 2.7 3.7 3.5 63 Asset 3.7 4.3 2.7 3.3 3.3 3.5 64 Amazon 4.0 4.0 3.0 2.0 3.7 3.5 65 Challenger 4.0 4.7 2.7 3.0 3.3 3.5 66 Blacksburg 3.7 5.0 3.0 2.0 4.0 3.5 67 NE 80-30 3.0 4.3 2.7 3.0 4.3 3.5 68 Barzan 4.0 4.0 2.0 3.3 3.7 3.4 69 BA 69-82 3.3 5.0 2.3 2.3 4.0 3.4 70 Midnight 4.0 5.0 2.3 2.3 3.3 3.4 71 Conni 3.0 3.3 2.7 3.3 4.3 3.3 72 BA 72-500 4.3 4.3 2.3 2.0 3.7 3.3 73 BA 73-540 4.0 4.7 2.0 2.7 3.3 3.3 74 Compact 3.3 4.0 2.3 2.7 3.3 3.1 75 Syd sport 3.3 4.0 2.0 2.7 3.3 3.1 76 Cheri 4.0 4.7 2.0 2.0 3.0 3.1 77 BA 72-492 2.7 4.0 2.3 2.0 4.0 3.0 78 80-55 3.0 4.0 2.0 3.0 3.0 3.0 79 BA 70-139 3.3 4.0 2.0 2.0 3.0 2.9 80 HV 97 3.0 4.0 2.0 2.3 3.0 2.9 LSD(005) 1.6 1.4 1.3 1.7 NS 1.0 Table 3. The 1991 quality ratings for the low-maintenance, non-irrigated regional Kentucky bluegrass test that was established in the fall of 1990. Cultivar April May June July Aug Oct Mean 1 PST-A7-111 6.7 7.3 7.0 7.0 6.3 6.7 6.8 2 GEN-RSP 7.0 7.3 7.3 6.7 5.0 6.0 6.6 -13- Cultivar April May June July Aug Oct Mean 3 MN 2405 6.3 6.3 6.7 6.0 7.0 6.0 6.4 4 Bronco 5.7 5.7 7.0 6.7 6.3 6.3 6.3 5 Kenblue 6.3 7.3 6.0 5.7 6.3 5.7 6.2 6 Alene 6.7 7.0 6.3 5.3 5.7 6.0 6.2 7 Park 6.0 7.0 6.3 6.0 5.7 5.7 6.1 8 Barmax 7.3 7.3 7.0 6.0 4.3 4.7 6.1 9 PST-YQ 6.0 6.0 6.3 6.0 6.3 5.7 6.1 10 South Dakota Cert. 6.3 5.7 6.7 6.0 5.3 6.0 6.0 11 NJIC 6.7 6.7 6.7 6.3 4.0 5.3 5.9 12 Ram I 5.0 5.0 6.7 6.7 6.3 5.7 5.9 13 ZPS-84-749 6.0 6.0 6.0 5.7 6.3 5.3 5.9 14 Voyager 6.3 6.0 6.7 6.0 5.0 5.7 5.9 15 Gnome 5.3 5.7 6.3 6.0 6.3 6.0 5.9 16 BAR VB 895 5.7 5.7 6.3 6.3 6.0 4.7 5.8 17 BA 78-376 6.3 6.0 5.7 5.7 5.7 5.3 5.8 18 Sophia 5.3 5.0 6.7 6.0 5.7 6.3 5.8 19 BAR VB 7037 4.0 5.3 6.3 6.3 6.0 5.7 5.8 20 Monopoly 6.0 6.3 6.7 5.7 5.0 4.7 5.7 21 ISI-21 6.0 6.3 6.3 5.3 5.0 5.3 5.7 22 PST-C-391 5.3 5.7 6.7 6.0 5.7 4.7 5.7 23 J-229 5.3 5.7 6.0 5.7 5.3 6.0 5.7 24 Haga 5.3 6.0 6.7 6.3 5.0 5.0 5.7 25 Opal 5.3 5.3 6.7 5.3 5.7 5.7 5.7 26 Baron 5.0 5.0 6.7 6.0 5.3 5.7 5.6 27 Miracle 4.7 5.3 6.0 6.3 5.7 5.7 5.6 28 PST-C-303 5.3 5.0 6.3 6.0 5.3 5.7 5.6 29 Suffolk 5.0 5.7 6.0 5.7 5.3 6.0 5.6 30 Washington 6.3 5.3 6.0 5.7 5.3 4.3 5.5 31 Freedom 5.0 5.3 5.7 5.7 6.0 5.3 5.5 32 Destiny 5.3 5.7 6.0 5.3 5.3 5.0 5.4 33 Merit 5.0 5.7 5.7 5.7 5.0 5.0 5.3 34 Crest 5.0 5.0 5.3 5.3 5.7 5.3 5.3 - 14 - Cultivar April May June July Aug Oct Mean 35 Livingston 5.0 5.3 6.0 5.7 5.3 4.7 5.3 36 PST-C-76 5.3 5.7 5.3 5.7 5.0 4.7 5.3 37 H76-1034 5.7 6.0 5.3 5.3 5.0 4.7 5.3 38 BA 74-017 5.0 5.0 5.0 5.3 5.3 5.7 5.2 39 Amazon 4.0 4.3 5.7 5.3 5.7 6.3 5.2 40 EVB-13.863 3.7 4.0 5.0 5.7 6.0 5.7 5.0 41 Cynthia 4.3 4.7 5.3 5.0 4.7 5.3 4.9 42 Midnight 4.7 5.3 5.3 5.3 4.3 4.3 4.9 43 Nustar 4.0 4.7 5.3 5.0 5.3 5.0 4.9 44 J-386 5.3 4.3 5.0 4.3 5.3 5.0 4.9 45 Chelsea 4.0 4.7 5.3 4.7 5.3 5.3 4.9 46 BAR VB 1169 3.7 4.3 5.7 5.3 5.0 5.3 4.9 47 Fortuna 4.3 4.3 4.3 5.0 5.7 5.0 4.8 48 Liberty 4.7 4.7 4.7 5.0 5.0 4.7 4.8 49 KWS PP 13-2 4.7 5.0 5.7 5.0 4.3 4.0 4.8 50 798 4.3 4.3 5.0 5.3 4.3 4.7 4.7 51 Unknown 5.0 4.0 4.7 4.7 5.0 5.0 4.7 52 J-335 4.0 4.7 5.3 5.3 4.7 4.3 4.7 53 SR 2000 5.0 5.3 4.7 4.3 4.0 4.7 54 NE 80-47 4.3 4.3 4.7 5.0 4.7 4.7 4.6 55 Cobalt 4.0 4.3 4.7 5.0 4.7 4.7 4.6 56 Barsweet 3.3 3.3 4.7 4.3 4.7 4.7 4.2 57 EVB-13.703 3.7 4.0 4.7 4.7 4.3 4.0 4.2 58 Barzan 2.7 3.3 4.0 4.7 5.0 5.0 4.1 59 Bartitia 3.7 3.3 3.7 4.3 4.7 4.7 4.1 60 Kyosti 3.7 4.3 4.3 4.7 3.3 3.0 3.9 61 BAR VB 1184 3.3 3.3 4.3 4.3 4.0 4.3 3.9 62 Merion 3.0 2.7 3.3 3.7 3.0 3.0 3.1 LSD(0o5) 1.2 1.4 1.2 1.2 1.4 1.5 1.0 4.7 - 15- The Recovery of Kentucky Bluegrass Cultivars Following Summer Dormancy Nick Christians In earlier work at Iowa State University (Grounds Maintenance 24(8):49-50) it was shown that Kentucky bluegrass cultivars vary greatly in their recovery from summer dormancy. Common, or public varieties, generally recover much more rapidly from drought-induced dormancy than do the newer improved cultivars. The objectives of this study were to further evaluate four cultivars that were previously shown to recover rapidly from dormancy and four cultivars that were slower to recover when maintained under low and high fertility regimes: 1 lb N/1000 ft2 in September and 4 lb N/1000 ft2 applied in 1 lb applications in April, May, August, and September. South Dakota Common, S-21, Kenblue, and Argyle (cultivars observed to recover rapidly in earlier studies) and Midnight, Nassau, Glade, and Ram I (cultivars observed to recover more slowly) Kentucky bluegrass were established in 21 ft2 plots on September 26, 1989, on a nonirrigated site at the turfgrass research area of the Iowa State University Horticulture Research Station north of Ames, Iowa. The soil on the site is a Nicolett (fine-loamy, mixed mesic, Aquic Hapludoll) with a pH of 6.8 and 2.3% organic matter, a P content of 20 lbs/A, and a K content of 216 lbs/A. The study was replicated three times. Each plot was split in half. The two fertility treatments were randomly applied to the two halves of the plots. The 1990 season was very wet and at no time did the grasses on the study area go into summer dormancy. The spring of 1991 was also very wet. By May, 1991 all cultivars were uniformly established. It became very dry beginning in June and the grass went into a dormancy period. The drought extended into August, at which time late summer rains began to bring the grass out of dormancy. Quality ratings based on a scale of 9 to 1 (9 = best quality, 6 = acceptable, 1 = dead turf) were collected on the area in late August and late September. South Dakota Common, S-21, Kenblue, and Argyle showed the best recovery following the drought in late August (Fig. 1). While each of these cultivars regained an acceptable quality very quickly after the drought, the four improved cultivars, Midnight, Nassau, Glade and Ram I, recovered more slowly. The improved cultivars were especially slow to recover at the low fertility level, whereas the common cultivars recovered well even at the low fertility level. This trend continued into September (Fig. 2). The higher recovery in September at the higher fertility level is due to the September fertilizer treatment. Nassau and Glade reached an acceptable quality rating at the high fertility level in September but Midnight and Ram I did not. As in earlier studies, the improved cultivars were very slow to recover following extended drought. Low fertility levels tended to affect the common cultivars less than the improved cultivars. This work will continue for 3 to 4 more seasons to observe the long-term effects of fertility level on the drought recovery of these eight Kentucky bluegrass cultivars. - 16- D bp E - 17- CULTIVAR AUGUST QUALITY RATINGS OF 0 KENTUCKY BLUEGRASS - 18- CULTIVAR SEPT. QUALITY RATINGS OF 8 KENTUCKY BLUEGRASS National Perennial Ryegrass Study S. M. Berkenbosch and N. E. Christians This trial began in the fall of 1990 with the establishment of 125 perennial ryegrass cultivars at the Iowa State University Horticulture Research Station. The study was established on an irrigated area and maintained at a 2-in mowing height. The area was fertilized with 3 to 4 lb N/1000 ft2/yr. The area receives preemergence herbicide in the spring and a broadleaf herbicide in September. Cultivars were evaluated for turf quality each month of the growing season. Ratings were low because this was the establishment year. The values listed under each month in Table 4 are the averages of ratings made on three replicated plots for the three studies. Yearly means of data from each month were taken and listed in the last column. Pick 89LLG, PST-20G, and Pick 89-4 were the top three performers in the first year. The cultivars are listed in descending order of average quality. Table 4. The 1991 quality ratings for the national perennial ryegrass study. Cultivar May June July August September Mean Pick 89LLG 8.0 7.0 6.0 6.0 6.0 6.6 PST-20G 6.7 6.3 6.6 6.7 6.7 6.6 Pick 89-4 6.7 6.0 6.6 6.7 6.7 6.5 PST-GH-89 7.7 6.3 6.0 6.3 6.3 6.5 EEG 358 7.0 6.3 6.0 6.3 6.3 6.4 Poly-SH 7.0 6.3 6.3 6.3 6.0 6.4 4DD-Delaware Dwa 6.3 6.0 6.3 6.7 6.3 6.3 Pick DKM 6.7 6.7 6.0 6.3 6.0 6.3 PST-28M 6.7 6.0 6.3 6.3 6.3 6.3 WVPB-89-PR-A-3 7.0 6.0 6.0 6.0 6.0 6.2 Pinnacle 6.8 5.8 6.0 6.3 6.0 6.2 HE 311 6.7 5.7 6.3 6.0 6.3 6.2 PST-2FQR 6.3 6.0 6.0 6.3 6.0 6.1 PS-105 6.7 5.7 6.0 6.0 6.0 6.1 2P2-90 6.7 5.7 6.0 6.3 6.0 6.1 PST-2DPR 7.0 6.0 5.7 5.7 5.7 6.0 Rodeo II 6.7 5.7 6.0 5.7 6.0 6.0 Cultivar May June July August September Mean Nomad 7.0 6.0 5.7 5.7 5.7 6.0 KOOS 90-1 6.7 5.3 6.0 5.7 5.7 5.9 GEN-90 6.7 5.7 5.7 5.7 5.7 5.9 PR 9108 6.0 5.7 6.0 6.0 6.0 5.9 SYN-P 6.7 6.3 5.3 5.7 5.7 5.9 Charger 6.0 5.0 6.0 6.0 6.3 5.9 PST-2B3 5.7 5.3 6.0 6.3 6.0 5.9 89-666 6.0 5.7 5.7 6.0 6.0 5.9 PR 9109 5.7 6.7 5.7 5.7 5.7 5.9 Advent 6.0 5.7 6.0 6.0 6.0 5.9 KOOS-90-2 6.7 5.3 5.7 5.7 5.7 5.8 BAR LP 086FL 6.5 5.3 5.8 5.8 5.5 5.6 Duet 5.3 5.7 6.0 5.7 6.3 5.8 PR 9119 6.0 5.0 6.0 6.0 6.0 5.8 PR 8820 (Essence) 6.7 5.3 5.7 5.7 5.7 5.8 Pick 1800 6.0 6.0 5.7 5.7 5.7 5.8 N-33 6.0 5.0 6.0 6.0 6.0 5.8 2H7 6.7 5.3 5.7 5.7 5.7 5.8 PST-23C 6.3 5.7 5.7 5.7 5.7 5.8 MVF 89-88 6.3 4.7 6.0 6.0 6.0 5.8 OFI-D4 6.0 5.3 6.0 5.7 6.0 5.8 LDRF 6.7 6.0 5.3 5.7 5.3 5.8 Assure 6.7 5.0 5.3 5.7 5.7 5.7 Dandy 5.7 6.0 5.7 5.7 5.7 5.7 MOM LP 3147 5.7 5.0 6.0 5.7 6.0 5.7 Gettysburg 6.7 5.7 5.3 5.3 5.3 5.7 Pebble Beach 6.3 6.0 5.3 5.3 5.7 5.7 WVPB-89-87A 6.3 5.0 5.7 5.7 5.7 5.7 Cutless 6.3 5.0 5.7 5.7 5.7 5.7 ZPS-28D 6.7 5.7 5.3 5.3 5.3 5.7 PST-2ROR 6.3 5.7 5.3 6.7 5.3 5.7 PST-2FF 5.7 5.3 5.7 6.0 5.7 5.7 Cultivar May June July August September Mean C-21 5.7 6.0 5.7 5.7 5.7 5.7 MVF 89-90 6.3 6.0 5.3 5.7 5.3 5.7 PR 9118 6.3 4.7 6.0 5.7 6.0 5.7 SR 4200 7.0 5.7 5.3 5.3 5.0 5.7 OFI-F7 6.0 5.3 5.7 5.7 5.7 5.7 Target 7.0 5.7 5.3 5.3 5.3 5.7 APM 6.3 5.3 5.7 5.7 5.7 5.7 WM-II 6.0 4.7 6.0 6.0 6.0 5.7 Calypso 5.7 5.7 5.3 5.7 5.7 5.6 ZW 42-176 6.7 5.3 5.3 5.3 5.3 5.6 Repell 6.0 5.7 5.3 5.7 5.3 5.6 BAR LP852 6.0 6.0 5.3 5.7 5.7 5.5 Barrage ++ 5.7 5.0 5.3 5.7 5.7 5.5 Commander 4.3 5.7 5.3 6.0 6.0 5.5 WVPB 89-92 6.7 4.7 5.3 5.3 5.3 5.5 Pleasure 6.0 5.0 5.3 5.7 5.3 5.5 WVPB-88-PR-D-12 6.0 4.7 5.3 5.7 5.7 5.5 Fiesta II 6.0 5.3 5.3 5.3 5.3 5.5 Meteor 5.7 5.0 5.7 5.3 5.7 5.5 Pennant 5.3 5.3 5.3 5.7 5.7 5.5 Competitor 6.3 5.3 5.3 5.3 5.3 5.5 Derby Supreme 6.0 5.3 5.3 5.3 5.3 5.5 CLP 144 6.7 5.3 5.0 5.3 5.3 5.5 Manhattan II (E) 6.0 5.3 5.3 5.3 5.3 5.5 P89 7.3 6.0 4.7 5.0 4.7 5.5 Danaro 6.0 4.7 5.0 5.7 5.7 5.4 WVP-88-PR-C-23 6.0 4.7 5.3 5.7 5.3 5.4 Sherwood 6.0 5.0 5.3 5.3 5.3 5.4 PR 9121 6.7 5.0 5.0 5.3 5.0 5.4 Express 6.0 4.7 5.3 5.3 5.7 5.4 Patriot II 6.7 5.3 5.0 5.3 4.7 5.4 Equal 6.0 5.0 5.3 5.3 5.3 5.4 -21 - Cultivar May June July August September Mean Barrage 6.0 5.3 5.0 5.0 5.0 5.3 MOM LP 3184 5.3 5.0 5.3 5.3 5.3 5.3 CLP 39 6.3 5.0 5.0 5.0 5.0 5.3 Gator 6.0 5.0 5.0 5.3 5.3 5.3 Pick EEC 7.0 5.3 4.7 4.7 5.0 5.3 Troubadour 5.7 5.0 5.0 5.3 5.3 5.3 Entrar 6.0 4.7 5.3 5.3 5.3 5.3 Citation II 6.0 5.3 5.0 5.3 5.0 5.3 ZPS-2EZ 5.7 5.3 5.0 5.3 5.3 5.3 Envy 6.0 4.7 5.3 5.0 5.3 5.3 Saturn 6.0 5.0 4.7 5.3 5.3 5.3 856 5.0 4.3 5.7 5.7 5.7 5.3 MOM LP 3182 5.7 4.7 5.0 5.7 5.7 5.3 PST-290 6.3 5.0 5.0 4.7 5.0 5.2 Unknown 5.7 5.0 5.0 5.0 5.3 5.2 LDRD 7.0 5.3 4.3 4.7 4.7 5.2 Riviera 5.7 5.0 4.7 5.0 5.0 5.1 Seville 6.3 5.0 4.7 4.7 4.7 5.1 Allegro 6.7 5.0 4.7 4.7 4.7 5.1 Taya 6.7 4.7 4.7 4.7 4.7 5.1 Premier 5.3 4.7 4.7 5.3 5.3 5.1 Pick 9100 7.0 5.0 4.3 4.3 4.7 5.1 Legacy 5.7 4.0 5.0 5.0 5.3 5.0 Loretta 6.3 4.7 4.3 4.7 4.7 4.9 WVPB-88-PR-D-10 5.7 4.7 4.7 4.7 4.7 4.9 Accolade 5.7 4.7 4.7 4.7 4.7 4.9 Surprise 5.3 5.3 4.7 4.7 4.7 4.9 Stallion 5.0 4.3 5.0 5.0 5.3 4.9 Ovation 5.0 4.3 4.7 5.0 5.0 4.8 NK 89001 5.3 5.3 4.0 4.7 4.7 4.8 MOM LP 3185 5.0 4.7 4.7 4.7 4.7 4.7 Regal 6.0 5.7 3.3 4.7 4.0 4.7 -22- Cultivar May June July August September Mean Lindsay 6.0 4.0 4.5 4.5 4.5 4.7 MOM LP 3111 5.3 4.7 4.3 4.3 4.7 4.7 Caliente 5.0 4.7 4.3 4.7 4.3 4.6 Danilo 6.0 5.0 4.0 4.0 4.0 4.6 Cartel 5.0 4.7 4.0 4.7 4.7 4.6 Goalie 5.3 4.3 4.3 4.3 4.3 4.5 Toronto 5.0 4.3 4.0 4.3 4.7 4.5 MOM LP 3179 5.0 4.0 4.0 5.0 4.7 4.5 Pennfine 5.0 4.3 4.0 4.3 4.3 4.4 Linn 4.0 3.7 4.3 4.7 5.0 4.3 LSD(005) 0.8 1.3 1.2 3.0 1.2 0.8 Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. -23- Regional Fine Fescue Cultivar Evaluation R. W. Moore and N. E. Christians This was the first year of data on this trial. It was established in the spring of 1990. The study was conducted in conjunction with several identical trials across the country, coordinated by the USDA. The purpose of the trial is to identify regional adaptation of 95 fine fescue cultivars. Cultivars were evaluated for quality each month of the growing season through October. Three replications of the 95 3-ft x 5-ft (15 ft2) plots were established in a 5 ft by 19 ft grid. The average seeding rates were approximately 55 g per plot or about 8 lb/1000 ft2. The trial was maintained at a 2-in mowing height, 3 to 4 lb N/1000 ft2 were applied during the growing season, and irrigated when needed to prevent drought. Preemergence herbicide was applied once in the spring and broadleaf herbicide was applied once in September to control weeds. 'Jamestown IT performed best in 1991 (Table 5). 'SR 5000', 'PST-4CD', 'Epsom', 'N-105', 'Southport', 'Longfellow', '89.LKR', 'PST-4C8', and 'Herald' were the top 10 cultivars. 'MX-86', 'Silvana', 'Valda', and 'Barreppo' received the poorest quality ratings. This data is for the first year following establishment and successive years may yield different results as the cultivars mature. Table 5. The 1991 quality ratings for the fine fescue regional cultivar trial. Cultivar July August September October November Mean 1 Jamestown II 7.7 7.3 8.0 8.0 8.0 7.8 2 SR 5000 8.0 6.7 7.7 8.0 8.0 7.7 3 PST-4CD 7.7 7.0 8.0 8.0 8.0 7.7 4 Epsom 7.7 7.0 8.0 8.0 7.7 7.7 5 N-105 7.7 7.0 7.7 8.0 8.0 7.7 6 Southport 8.0 7.0 7.7 8.0 8.0 7.7 7 Longfellow 8.0 7.0 7.3 8.0 8.0 7.7 8 89.LKR 7.7 7.0 8.0 8.0 8.0 7.7 9 PST-4C8 7.0 7.0 8.0 8.0 8.0 7.6 10 Herald 7.3 7.6 8.0 8.0 8.0 7.6 11 PST-43F 7.7 7.0 7.7 7.7 7.7 7.5 12 PST-4FE 8.0 7.0 7.3 8.0 7.3 7.5 24- Cultivar July August September October November Mean 13 JMB-89 7.3 6.7 7.3 8.0 7.7 7.4 14 PST-4R3 7.0 7.0 7.7 7.7 7.7 7.4 15 PST-4NI 7.3 6.7 7.7 7.7 7.7 7.4 16 PST-SHE 7.3 7.0 7.0 7.7 7.7 7.3 17 Cindy 7.7 6.7 7.7 7.3 7.3 7.3 18 Banner 7.7 7.0 7.0 7.7 7.3 7.3 19 OFI-89-200 7.3 6.3 7.3 8.0 7.7 7.3 20 Shadow 7.7 6.7 6.7 7.7 7.3 7.2 21 Salem 6.7 7.0 7.0 8.0 7.3 7.2 22 NK 82492 7.3 6.3 7.0 7.7 7.3 7.1 23 Molinda 7.0 6.7 6.7 7.3 7.7 7.1 24 BAR FR 9F 7.3 7.0 6.3 7.7 7.0 7.1 25 Bargreen 7.7 6.7 6.7 7.7 7.0 7.1 26 Scarlet 7.3 7.0 6.7 7.7 7.0 7.1 27 Mary 7.0 7.0 6.3 7.7 7.3 7.1 28 Dawson 7.0 7.0 6.7 7.7 7.0 7.1 29 Jasper 7.0 6.7 7.0 7.3 7.3 7.1 30 Wilma 7.7 6.3 6.7 7.7 7.0 7.1 31 Puma 7.3 6.3 6.7 8.0 7.0 7.1 32 Atilla 7.7 6.3 6.3 7.7 7.0 7.0 33 Barcrown 8.0 6.7 6.3 7.3 6.7 7.0 34 Atlanta 7.7 6.0 6.3 7.3 7.7 7.0 35 HF 112 7.7 6.3 6.7 7.3 7.0 7.0 36 Waldorf 8.0 6.3 6.3 7.3 7.0 7.0 37 Capital 7.0 6.7 7.0 7.3 7.0 7.0 38 Fot 30149 7.3 6.0 6.7 7.3 7.3 6.9 39 HF 138 7.0 7.0 6.7 7.0 7.0 6.9 40 Koket 7.3 6.7 6.7 7.0 7.0 6.9 41 LD 3485 7.3 6.3 7.0 7.0 6.7 6.9 42 Camaro 7.0 6.3 6.7 7.0 7.0 6.8 43 Barlotte 7.3 6.7 6.0 7.0 7.0 6.8 44 Bamica 7.3 6.3 6.3 7.0 7.0 6.8 -25- Cultivar July August September October November Mean 45 ZW 42-160 8.0 6.7 6.0 6.7 6.7 6.8 46 Jamestown 7.3 6.3 6.3 7.3 6.7 6.8 47 Vista 6.7 6.0 6.7 7.3 7.3 6.8 48 Enjoy 7.7 6.3 6.0 7.3 6.7 6.8 49 WW RS 130 7.0 6.3 6.7 7.0 6.3 6.7 50 WW RS 138 6.7 6.3 6.3 7.0 7.3 6.7 51 BAR FR 9F 7.0 6.3 6.3 7.0 6.7 6.7 52 Shademaster 6.0 6.3 7.0 7.0 7.3 6.7 53 Flyer 6.7 6.0 6.7 7.0 7.0 6.7 54 Rainbow 7.0 6.7 6.3 7.0 6.3 6.7 55 SRX 89-31 7.0 5.7 6.0 7.7 6.7 6.6 56 LD 3488 7.3 6.3 5.7 7.0 6.7 6.6 57 Raymond 7.0 6.0 6.3 6.7 6.7 6.5 58 Estoril 7.7 6.0 6.3 6.7 6.0 6.5 59 Boreal 6.0 6.3 6.7 7.0 6.3 6.5 60 ZW 42-148 6.3 6.3 6.3 7.0 6.0 6.4 61 Elanor 6.7 6.3 6.0 6.7 5.7 6.3 62 Franklin 6.3 5.7 6.3 6.3 6.7 6.3 63 WW RS 143 6.7 6.0 6.0 6.3 6.7 6.3 64 BAR FO 9A2 6.3 5.3 6.3 7.0 6.7 6.3 65 Aurora 6.0 5.7 6.0 7.3 6.3 6.3 66 Belvedere 6.7 6.0 6.3 6.3 6.3 6.3 67 Bargena 6.3 5.7 5.7 6.7 7.0 6.3 68 NK 88001 6.3 6.7 6.3 6.3 6.0 6.3 69 Claudia 5.7 6.0 6.0 7.0 7.0 6.3 70 ERG 1143 6.3 6.3 6.3 6.3 6.0 6.3 71 LD 3414 6.3 6.0 6.0 6.7 6.3 6.3 72 Melody 6.0 5.3 5.7 7.0 7.0 6.2 73 BAR FR 8RC3 5.7 6.0 6.7 7.0 5.7 6.2 74 Bighorn 6.0 6.0 6.0 7.0 5.7 6.1 75 HF 102 5.7 5.7 6.0 6.7 6.3 6.1 76 Warwick 6.0 5.7 5.7 7.0 6.3 6.1 -26- Cultivar July August September October November Mean 77 Crystal 6.0 5.3 6.0 6.3 6.7 6.1 78 Sylvester 6.0 5.7 6.0 6.7 5.7 6.0 79 Ensylva 5.3 6.0 6.0 6.3 6.3 6.0 80 Marker 6.3 5.3 5.7 6.7 6.0 6.0 81 LD 3438 6.3 6.0 6.0 6.3 5.3 6.0 82 PST-4HD 5.7 5.0 5.3 7.0 6.3 5.9 83 Reliant w/o endo. 5.3 6.0 5.3 6.7 6.3 5.9 84 PST-AUE 6.3 4.7 5.0 6.3 6.0 5.7 85 Reliant w/endo. 5.0 5.0 5.3 6.7 6.3 5.7 86 Biljart 5.7 5.0 5.3 6.3 6.0 5.7 87 Scaldis 6.0 5.7 5.7 6.3 5.3 5.6 88 SR 3000 5.7 5.0 5.0 6.3 6.0 5.6 89 PST-4AG 5.3 4.7 5.3 6.7 6.0 5.6 90 Serra 4.7 5.3 4.7 6.7 6.0 5.5 91 Eureka 5.3 5.0 5.0 6.3 5.7 5.5 92 MX-86 5.0 5.3 5.3 5.7 5.0 5.3 93 Silvana 5.3 4.3 5.0 6.0 5.7 5.3 94 Valda 4.7 4.7 5.3 6.0 6.0 5.3 95 Barreppo 4.7 4.3 5.3 5.7 5.0 5.0 l s d {005) 1.4 1.0 1.2 1.1 1.2 0.9 Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. -27- Tall Fescue Cultivar Trial M. L. Agnew and N. E. Christians The 65 tall fescue cultivars were established in the fall of 1987 at the Iowa State University Horticulture Research Station. The study was maintained at a 2-in mowing height and fertilized with 2 lb N/1000 ft2/yr. The area was unirrigated and receives no fungicide or insecticide applications. The data in Table 6 reflects the quality data from 1991. Rainfall was heavy in the spring. Interestingly, Shenandoah and Tribute were tall fescue cultivars that also grew well under drought conditions. Table 6. Mean turfgrass quality ratings of tall fescue cultivars in the 1987 National Tall Fescue Test at Ames, Iowa. 1991 Data. Monthly Rating3 Tall Fescue Cultivar May June July Aug Sept Oct Mean KWS-BG-6 (Twilight) 7.0 7.7 7.3 8.3 6.0 8.0 7.4 BEL 86-2 6.3 7.3 8.3 7.7 6.7 7.3 7.3 PE-7E (Shenandoah) 7.3 7.0 7.3 8.3 6.3 7.7 7.3 Tribute 7.0 7.0 7.3 8.3 6.3 8.0 7.3 Sundance 7.0 7.3 7.7 7.7 6.0 7.3 7.2 Pick DDF (Shortstop) 7.7 7.3 6.7 7.0 6.0 7.7 7.1 Apache 7.0 6.7 7.0 7.3 6.0 7.3 6.9 Hubbard 87 8.3 7.7 7.3 7.0 4.0 7.0 6.9 KWS-DUR 7.7 7.0 6.7 7.7 5.3 7.0 6.9 Normare 77 (Phoenix) 7.0 7.7 7.7 7.0 5.3 7.0 6.9 Normare 99 (Vegas) 7.0 7.0 7.3 7.0 6.0 7.0 6.9 PST-5AP 7.3 7.0 7.0 7.3 6.0 7.0 6.9 Mesa 6.3 7.0 7.3 7.0 5.3 7.7 6.8 Pick 127 (Cochise) 8.0 8.0 8.3 6.0 3.7 6.7 6.8 PST-5D1 (Eldorado) 6.3 7.0 7.3 7.7 4.7 8.0 6.8 PST-5F2 (Winchester) 7.3 7.0 7.0 7.0 5.7 7.0 6.8 Trident 6.7 7.0 6.7 7.0 6.3 7.0 6.8 BAR FA 7851 (Bamone) 6.7 6.3 6.7 7.3 5.7 7.3 6.7 28 Monthly Rating3 Tall Fescue Cultivar May June July Aug Sept Oct Mean Chieftain 6.7 7.3 6.7 7.0 5.3 7.3 6.7 Pick DM (Avanti) 7.0 7.0 6.7 7.0 5.3 7.3 6.7 PST-5HF (Amigo) 7.0 7.3 7.0 6.3 5.7 7.0 6.7 Cimmaron 7.0 7.0 6.7 7.0 5.0 7.0 6.6 PE-7 7.3 7.3 8.0 6.4 4.7 6.0 6.6 Pick 845PN (Guardian) 7.7 6.7 6.7 6.7 5.3 6.7 6.6 PST-5D7 (Murietta) 7.3 7.0 7.0 6.3 4.7 7.0 6.6 PST-5EN 7.0 7.0 6.7 7.0 5.0 7.0 6.6 PST-DBC (Tradition) 7.0 6.7 6.7 6.3 6.0 6.7 6.6 Thoroughbred 7.3 6.7 6.7 6.7 5.3 6.7 6.6 Bonanza 6.3 6.7 7.3 6.7 5.3 6.7 6.5 PST-5AG 6.0 6.3 7.0 6.7 5.7 7.3 6.5 Arid 5.7 6.7 6.7 7.3 5.3 7.0 6.4 PST-5DM (Arriba) 7.7 7.7 7.0 6.0 4.3 6.0 6.4 Taurus 6.3 7.0 7.0 6.7 5.0 6.7 6.4 BEL 86-1 6.3 6.0 6.3 6.7 5.3 7.0 6.3 Jaguar II 7.0 7.0 7.0 6.0 4.3 6.7 6.3 Pick SLD (Emperor) 6.7 6.7 7.0 6.7 4.3 6.7 6.3 PST-5MW (Safari) 6.7 7.0 7.3 5.7 4.7 6.3 6.3 Rebel II 6.7 6.7 6.7 7.0 4.3 6.7 6.3 Titan 6.7 6.7 6.3 6.3 4.7 7.0 6.3 Finelawn 5GL 6.3 6.3 6.3 6.3 5.3 6.7 6.2 Legend (Brahma) 6.7 7.0 7.3 5.7 4.3 6.3 6.2 Normarc 25 (Austin) 7.0 7.0 7.0 5.7 4.3 6.3 6.2 PST-5BL (Silverado) 8.0 7.3 7.3 5.3 3.0 6.0 6.2 PST-50L (Olympic II) 6.0 6.3 6.3 6.3 5.7 6.3 6.2 Pick TF9 (Crossfire) 7.3 7.3 7.3 5.0 4.0 5.7 6.1 Aztec 7.0 7.3 7.7 4.7 3.3 5.3 5.9 Carefree 6.0 6.3 6.3 6.7 4.0 6.3 5.9 Falcon 7.0 7.0 6.7 5.0 3.7 6.0 5.9 Pacer 6.0 6.0 6.3 6.0 4.7 6.3 5.9 -29- Monthly Rating3 Tall Fescue Cultivar May June July Aug Sept Oct Mean Pick GH6 (Maverick II) 7.3 6.7 6.7 5.3 4.0 5.7 5.9 Fatima 5.7 6.3 6.7 6.0 4.0 6.0 4.8 Jaguar 6.0 6.7 7.0 5.3 4.0 5.7 5.8 Rebel 6.0 5.7 5.7 6.0 5.3 6.3 5.8 SYN GA (Aquara) 6.0 6.3 6.3 6.0 4.0 6.3 5.8 Finelawn I 6.3 6.3 6.0 5.3 4.3 5.7 5.7 Monarch 6.3 6.3 7.0 5.7 3.3 5.7 5.7 Olympic 6.7 6.7 6.7 4.7 4.0 5.3 5.7 Richmond 5.7 6.0 6.0 5.7 4.7 6.0 5.7 Adventure 6.0 6.0 6.0 5.0 4.3 5.7 5.5 JB-2 6.0 6.3 6.0 5.0 3.7 5.3 5.4 Tip 6.0 6.0 5.3 4.7 4.7 5.7 5.4 Trailblazer 7.7 6.7 5.3 4.3 3.0 5.3 5.4 Willamette 5.7 6.3 6.3 5.0 3.7 5.3 5.4 Wrangler 6.7 6.3 6.3 5.0 3.3 5.0 5.4 KY-31 5.7 6.3 6.0 4.7 3.0 6.0 5.3 LSD(0.05) 1.8 1.4 2.2 2.0 2.8 2.4 1.4 3Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. - 3 0- Shade Adaptation Study - 1991 N. E. Christians The shade adaptation study was established in the fall of 1987 to evaluate the performance of 35 species and cultivars of grasses. The species include creeping red fescue (C.R.F.), hard fescue (H.F.), tall fescue (T.F.), Kentucky bluegrass (K.B.), and rough bluegrass trivialis). The area is located under the canopies of a mature stand of Siberian elm trees ( pumila) at the Iowa State University Horticulture Research Station. The grasses were mowed at a 2-in height and received 2 lb N/1000 ft2/year. No weed control has been required on the area. The area was irrigated during extended droughts. Monthly quality data was collected from May through September. The hard fescues (H.F.) and creeping red fescue (C.R.F.) were the best performers in 1990 (see last year's report), but in the very wet conditions of 1991, these species deteriorated badly (Table 7). The tall fescues maintained very good quality all season long in 1991. Some of the Kentucky bluegrasses also maintained an acceptable quality through much of the season. Sabre ( trivialis) performed very poorly in the earlier, drier years of the test, but in the wet conditions of 1991 this species performed the best of all grasses in the study. Table 7. The 1991 quality ratings for grasses in the shade trial. Cultivar May June July August September Mean Poatrivialis)7.3 8.0 7.0 4.7 7.3 6.9 1 Sabre ( 2 Bonanza (T.F.) 5.3 7.0 7.3 6.0 6.7 6.5 3 Chateau (K.B.) 6.0 6.0 6.3 6.0 6.7 6.2 4 Apache (T.F.) 6.0 6.7 7.0 5.0 5.3 6.0 5 Arid (T.F.) 5.3 6.0 6.3 5.7 6.7 6.0 6 Midnight (K.B.) 6.0 6.3 6.3 5.0 5.7 5.9 7 Coventry (K.B.) 6.3 6.0 6.3 4.7 5.0 5.7 8 Waldorf (C.F.) 6.7 5.0 4.7 4.3 6.7 5.5 9 Glade (K.B.) 6.7 6.3 5.3 4.0 5.3 5.5 10 Rebel (T.F.) 5.7 5.0 5.7 5.3 5.0 5.3 11 Rebel II (T.F.) 5.7 5.0 5.0 5.0 5.7 5.3 12 Falcon (T.F.) 6.0 4.3 5.7 5.3 5.3 5.3 13 ST-2 (SR 3000) (H.F.) 7.0 4.3 4.0 4.7 5.3 5.1 14 Biljart (H.F.) 6.3 4.7 4.3 4.0 5.7 5.0 - 31 - Cultivar May June July August September Mean 15 Ram I (K.B.) 5.0 5.0 5.7 4.0 5.3 5.0 16 Atlanta (C.F.) 6.7 5.0 4.3 3.7 5.0 4.9 17 BAR FO 81-225 (H.F.) 6.7 4.3 4.3 3.7 5.7 4.9 18 Pennlawn (C.R.F.) 6.7 5.0 3.7 3.0 5.3 4.7 19 Shadow (C.F.) 6.7 4.7 3.3 3.3 5.3 4.7 20 Wintergreen (C.F.) 6.0 4.3 4.7 3.0 5.0 4.6 21 Banner (C.F.) 7.3 3.7 3.7 3.0 4.7 4.5 22 Victor (C.F.) 6.3 3.0 3.7 3.3 5.0 4.3 23 Jamestown (C.F.) 5.7 3.7 3.7 3.3 4.7 4.2 24 Koket (C.F.) 5.7 4.3 3.0 3.3 4.7 4.2 25 Estica (C.R.F.) 7.0 3.7 3.3 2.3 4.0 4.1 26 Waldina (H.F.) 5.7 3.3 3.3 3.3 4.7 4.1 27 Ensylva (C.R.F.) 4.7 3.3 3.3 3.7 5.0 4.0 28 Agram (C.F.) 6.0 4.3 2.7 2.7 3.7 3.9 29 Mary (C.F.) 6.0 3.7 3.3 2.7 4.0 3.9 30 Bristol (K.B.) 5.3 3.7 3.7 3.0 4.0 3.9 31 Scaldis (H.F.) 5.3 3.3 3.3 2.7 3.7 3.7 32 Highlight (C.F.) 5.7 3.0 2.7 2.3 4.0 3.5 33 Spartan (H.F.) 6.3 2.7 2.3 2.7 3.3 3.5 34 Nassau (K.B.) 4.0 3.7 3.0 3.3 3.0 3.4 35 Reliant (H.F.) 5.3 3.0 2.3 2.0 2.7 3.1 LSD(0.05) 1.3 1.5 1.7 1.7 NS 1.4 Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality - 32 - USGA Buffalograss Trial - 1991 N. E. Christians and R. W. Moore The USGA buffalograss trial consists of 5 buffalograss ( dactyloides) varieties developed as part of the USGA turfgrass breeding program that are being compared to a standard buffalograss variety, 'Texoka'. The trial was established in August of 1988 and suffered considerable winter kill because of the late planting date. Only variety 84-315 survived the first winter in a satisfactory condition. In November of 1989, plugs of all varieties were established in the greenhouse and were maintained during the winter of 1989-1990. All six field plots were reestablished in the last week of May, 1990. The summer of 1990 was very wet. These plugs established well during the growing season and all had reached 100% cover by dormancy in September 1990. First quality data on the study were collected in 1991 (Table 8). The 84-315 variety received the highest rating through the season. This was due in part to its early spring greenup and to its high density and uniformity. The 84-609, 84-304,and 84-409 do not appear to be well adapted to Iowa conditions. Data collection will continue for several more seasons on these grasses. Table 8. The 1991 quality ratings for the USGA buffalograss study. Cultivar May June July August Mean 1 84-315 9.0 9.0 7.3 7.3 7.3 2 Texoka 8.3 6.3 6.0 6.3 6.8 3 85-378 8.0 6.7 6.3 6.0 6.8 4 84-609 2.7 3.3 3.7 5.7 3.8 5 84-304 2.7 3.7 3.0 4.7 3.5 6 84-409 2.7 3.7 3.0 4.7 3.5 l s d (0.05) 1.4 1.3 1.1 0.8 0.7 Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality - 33- Green Height Bentgrass Cultivar Trial (Native Soil) N. E. Christians and R. W. Moore This is the first year of data for the 20 cultivars that were established in the fall of 1989 at the Iowa State University Horticulture Research Station. The study was reseeded in the spring of 1990 because of poor winter survival. The cultivars were maintained with a fertilizer program of 1/4 lb N applied at 14-day intervals with an approximate total of 6 lb of N/1000 ft2/growing season. A 3/16-in mowing height was used. Fungicides were used as needed in a preventative program. Herbicides and insecticides were applied only in a curative program. 'Penncross' (Table 9) had the best quality of any cultivar. Nine cultivars maintained a mean of 6 (acceptable) or better. Other top cultivars were 'WVPB 89-D-15', 'Bardot', 'Forbes 89-12', '88.CBL', and 'Normarc 101'. 'Pennlinks', 'Cobra', and 'SR 1020' were also in the top 9 cultivars. 'Egmont', 'BR 1518', and 'Allure' had the lowest quality ratings of the 20 cultivars. This was an establishment year and may not reflect the true attributes of these cultivars. The results may change as the study matures. - 34 - Table 9. The 1991 ratings for the green height bentgrass trial. Cultivar May June July August Mean 1 Penncross 6.7 6.7 6.0 7.7 6.8 2 WVPB 89-D-15 6.0 6.3 6.0 7.0 6.3 3 Bardot 7.0 6.3 5.7 6.3 6.3 4 Forbes 89-12 5.7 6.3 6.3 7.0 6.3 5 88.CBL 5.7 6.3 6.0 7.3 6.3 6 Normarc 101 5.3 6.7 5.7 7.0 6.2 7 Pennlinks 5.7 6.0 5.7 7.0 6.1 8 Cobra 5.7 6.0 5.0 7.3 6.0 9 SR 1020 5.3 6.0 6.0 6.7 6.0 10 Providence 3.3 6.3 6.7 7.3 5.9 11 Putter 4.7 6.7 5.7 6.7 5.9 12 88.CBE 5.3 6.3 6.0 6.0 5.9 13 Southshore 6.3 5.7 5.3 6.0 5.8 14 Carman 5.7 5.7 5.3 6.3 5.8 15 Tracenta1 6.7 5.7 5.7 4.7 5.7 16 Emerald 5.7 5.7 5.3 6.0 5.7 17 National 6.0 5.3 4.7 6.0 5.5 18 Egmont2 5.0 4.3 4.7 4.3 4.6 19 BR 15183 5.0 3.3 4.3 4.0 4.2 20 Allure1 4.7 4.0 4.3 3.7 4.2 LSD(0.05) 1.1 1.0 1.3 1.5 0.8 ’Tracenta and Allure are colonial bentgrasses, Agrostis tenuis. 2Egmont is a browntop bentgrass, Agrostis capillaris. 3BR 1518 is a dryland bentgrass, Agrostis castollana. Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. -35- Fairway Height Bentgrass Study - 1991 N. E. Christians The fairway height bentgrass study was established in the fall of 1988 to compare the response of several new cultivars of seeded bentgrasses with the older types. The grass was kept at an 0.5-in mowing height, the standard mowing height for creeping bentgrass fairways. The area received liquid applications of urea as needed during the season (0.2 lb N/1000 ft2/application in 3 gal water/1000 ft2). The total N application rate was approximately 3 lb/season. Fungicides and insecticides were used as needed. The area was irrigated as needed, but little irrigation was required until August because of the high rainfall in 1991. The best cultivars in 1991 were 'SR 1020', 'Putter', and 'Penneagle'. 'Penncross' quality ratings dropped from 1st place in 1990 to 12th place in 1991. This was a consistent trend during the year and the reason for it is uncertain. Table 10. Quality ratings for the fairway height bentgrass study in 1991*. Cultivar May June July August October Mean 1 SR 1020 7.3 8.0 7.7 7.3 8.3 7.7 2 Putter 6.3 8.3 8.0 8.0 7.3 7.6 3 Penneagle 6.3 8.3 7.7 8.0 7.3 7.5 4 Providence (SR 1019) 7.7 7.7 7.0 8.0 6.7 7.4 5 J.H. Bent 6.3 7.7 7.0 7.7 7.7 7.3 6 ISI 123 6.7 7.0 7.3 7.7 7.3 7.2 7 ISI 124 7.3 6.7 7.3 7.3 7.3 7.2 8 Pennlinks 7.0 7.7 6.3 7.0 7.3 7.1 9 Cobra 6.7 7.0 6.7 7.3 6.7 6.9 10 Emerald 6.0 6.7 7.0 8.0 7.0 6.9 11 Southshore 6.7 6.7 6.7 7.3 7.3 6.9 12 Penncross 6.3 6.7 6.7 7.3 7.3 6.9 13 Carmen 7.0 7.0 6.3 7.3 6.0 6.7 14 Exeter (Colonial Bent) 6.0 5.3 5.7 6.3 6.0 5.9 15 National 4.7 5.3 5.3 6.0 6.3 5.5 16 Prominent 5.0 5.0 5.3 5.7 5.7 5.3 LSD(005) 1.0 1.8 1.0 1.1 1.5 0.8 ^Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. -36- Fairway Height Kentucky Bluegrass Trial - 1991 N. E. Christians and R. W. Moore The Kentucky bluegrass plots in this trial were established in 1979 and the study was maintained at lawn height for nine seasons. In the fall of 1988, the mowing height was slowly reduced to 1 in to test the cultivars under conditions similar to a Kentucky bluegrass fairway. The study was irrigated as needed and fertilized at a rate of 4 lb N/1000 ft2/yr. 'Plush' performed best in 1991 (Table 11). 'Midnight' did very well, but it should be noted that this cultivar does not stand up well in dry years (see 1990 report) and develops severe powdery mildew if there is any shade in the area (the test area is in full sun). 'Majestic' was the lowest rated cultivar. This grass generally performs well at higher mowing heights, but under the low mowing heights of this study its quality deteriorated. - 37- Table 11. The 1991 quality ratings for the fairway height Kentucky bluegrass trial established in 1978. Cultivar May June July August October Mean 1 Plush 8.0 8.7 6.7 6.3 7.3 7.4 2 Midnight 7.0 7.0 7.3 7.3 6.7 7.1 3 (WTN) 1-13 7.7 7.0 7.0 7.3 6.7 7.1 4 Bristol 7.0 7.3 6.7 6.7 6.7 6.9 5 A-20-6 6.3 7.7 7.3 7.0 6.3 6.9 6 Parade 6.0 7.0 7.0 7.4 6.7 6.8 7 K3-160 6.7 7.0 7.0 6.7 6.7 6.8 8 (WTN) H-7 7.3 6.3 7.0 6.7 6.7 6.8 9 America 6.7 7.0 6.7 6.7 7.0 6.8 10 Escort 7.0 7.7 6.7 6.7 6.0 6.8 11 Aspen 7.0 7.0 6.0 6.7 6.7 6.7 12 Touchdown 7.3 6.7 5.7 7.0 7.0 6.7 13 Barbie 7.0 6.3 6.3 7.0 7.0 6.7 14 BFB-35 7.0 6.7 6.3 6.7 7.0 6.7 15 Victa 6.7 7.0 7.0 6.7 6.3 6.7 16 Rugby 6.7 6.7 6.7 6.7 6.7 6.7 17 Wabash 7.3 6.7 7.0 6.7 6.0 6.7 18 A-20 7.3 6.0 6.0 7.3 6.3 6.6 19 P-164 7.0 7.0 5.7 6.7 6.7 6.6 20 Cheri 6.7 7.0 6.3 6.7 6.3 6.6 21 Vantage 6.7 7.0 6.3 6.3 6.7 6.6 22 Bonnieblue 6.7 7.3 7.0 6.7 5.3 6.6 23 Glade 6.7 6.7 7.0 6.7 6.0 6.6 24 Common 6.7 6.7 6.3 6.3 6.7 6.5 25 N-535 6.7 7.7 6.0 6.0 6.0 6.5 26 Fanfare 6.7 7.0 6.3 6.3 6.0 6.5 27 Trenton 6.7 7.0 6.7 6.0 6.0 6.5 28 P-164B 7.0 6.7 5.7 7.0 6.0 6.5 29 Park 6.0 7.3 6.0 6.7 6.0 6.4 30 Merit 6.3 6.7 6.3 7.0 5.7 6.4 38 Cultivar May June July August October Mean 31 Merion 6.3 6.7 5.7 6.7 6.3 6.3 32 Sving 6.3 6.7 6.0 6.3 6.0 6.3 33 Baron 6.7 7.7 6.0 6.0 5.3 6.3 34 Enmundi 6.3 6.7 6.0 6.3 6.0 6.3 35 K76-86-4 6.7 6.3 6.7 6.3 5.7 6.3 36 Sydsport 6.3 6.7 6.3 5.7 6.0 6.2 37 Senic 6.3 6.0 6.0 6.3 6.3 6.2 38 Kimono 6.7 6.3 5.7 6.3 6.0 6.2 39 SVO 1617 6.3 7.0 5.7 6.3 5.7 6.2 40 Nugget 6.0 7.0 6.0 6.3 5.3 6.1 41 Arista 6.0 6.7 6.0 6.0 6.0 6.1 42 Fylking 6.7 6.3 5.7 5.7 6.0 6.1 43 A-34 6.3 7.0 5.7 6.3 5.0 6.1 44 Columbia 5.7 6.3 6.0 6.3 5.7 6.0 45 Aquila 6.7 6.0 6.3 6.3 4.7 6.0 46 Ram I 6.0 6.3 5.3 6.3 5.7 5.9 47 Adelphi 6.0 6.3 5.3 6.0 5.3 5.8 48 Birka 6.0 6.7 5.7 5.3 5.0 5.7 49 (WTN) A-34 6.0 6.0 5.0 5.0 5.3 5.5 50 Pennstar 6.0 5.3 5.0 5.3 5.7 5.5 51 Majestic 5.7 5.7 4.7 6.0 5.3 5.5 LSD(005) NS NS NS NS 1.4 NS Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality. -39- Preemergence Annual Weed Control Study - 1991 N. E. Christians, R. G. Roe, and D. L. Struyk The 1991 preemergence annual weed control study was conducted at the turfgrass research area on a Nicolett (fine-loamy, mixed mesic, Aquic Hapludoll) soil with a pH of 6.9 and 2.3% organic matter. The objective of the project was to evaluate the efficacy of several labeled and experimental preemergence herbicides applied to a 'Parade' Kentucky bluegrass turf for the control of crabgrass. Plots measured 5 ft by 5 ft. They were arranged in a randomized, complete-block design with three replications. The area was seeded in the second week of April with a combination of large hairy and smooth crabgrass harvested from the research area. Treatments were applied on April 24. Liquids were applied with a backpack carbon-dioxide sprayer equipped with 8006 nozzles at 20 psi. Granular materials were applied with a hand-held shaker. The study was irrigated following seeding and a heavy infestation of crabgrass developed in the control plots. Heavy rains in April, May, and June kept the area well watered and no additional irrigation was necessary following germination. The study was observed weekly for signs of phytotoxicity. No damage was observed on any of the treated plots at any time during the summer of 1991. This was true in spite of stress conditions during a dry period in late July and August. Estimates of the percentage reduction of crabgrass were made in July. Counts of crabgrass, prostrate spurge, and oxalis were made in August (Table 12). Ronstar 2G provided excellent crabgrass control at the 4 lb a.i./A rate as did Exp 03621B 2G (an experimental formulation of the same active ingredient). The 2 lb a.i. rates of these materials were also relatively effective. Split applications of Balan were not effective in controlling crabgrass. However, when an initial application of Balan was followed by either Pre M or Team, weed control was much improved. Split applications of Team 2G at 1.5 lb a.i. were very effective in 1991. Single applications of Dimension, Pendimethalin, and Dacthal provided rather poor weed control. This was probably due to very wet weather during the early crabgrass germination period in May and early June. The results for Dimension were surprising given the good control we have seen with this material in past years. Perhaps repeat applications of Dimension would be necessary in extremely wet years. Barricade provided reasonable crabgrass control with one application. Control was improved when Barricade was applied with Gallery. Gallery alone is not considered to be a crabgrass control. Its primary use is for control of annual broadleaf weeds. We tried it at higher than normal rates this year to determine if crabgrass control could be improved at higher rates. There was no satisfactory control of crabgrass with Gallery alone at any level used in this study. There were no statistically significant differences in spurge and oxalis counts among treatments. The counts for these two annual species are listed in Table 12 to show the average number of plants that were observed in the three replicated plots for each treatment. -40- Table 12. The 1991 preemergence annual weed control study. Crabgrass % Cover Spurge Count Oxalis Count Treatment Rate (# a.i./A) July August 1 Control — 18 65 0 0 2 Balan 60DF 2.0 + 2.0 8 wk 5 30 0 0 3 Balan 60DF, Pre M 60WP 2.0 + 1.5 8 wk 4 8 0 0 4 Balan 60DF, Team 2G 1.5 + 1.5 8 wk 3 9 1 0 5 Team 2G 1.5 + 1.5 8 wk 2 4 0 1 6 Team 2G 3.0 2 9 1 0 7 Balan 60DF 3.0 4 28 2 0 8 Gallery 75DF .75 13 57 3 0 9 Gallery 75DF 1.0 13 60 1 0 10 Gallery 75DF 1.5 10 68 0 0 11 Gallery 75DF .75 + .75 8 wk 12 42 0 0 12 Team 1.156G 1.5 + 1.5 8 wk 11 35 0 1 13 Pendimethalin 60WP 1.5 + 1.5 8 wk 4 28 0 0 14 Gallery/Team/ Fert. FN9064 2.72 10 38 1 0 15 Ronstar 2G 2.0 4 11 1 2 16 Ronstar 2G 4.0 0 1 3 0 17 EXP03621B 2G 2.0 3 6 0 1 18 EXP03621B 2G 4.0 0 1 0 1 19 EXP04742A 4EC 6.0 8 53 1 0 20 EXP30742B 2.3G 4.0 4 23 1 0 21 EXP30742B 2.3G 6.0 1 6 1 0 22 EXP30742B 2.3G 3.0 7 28 1 0 23 EXP30832A 2.3G 4.0 5 32 2 0 24 EXP30832A 2.3G 6.0 3 14 2 2 25 EXP30833A 2.3G 4.0 3 27 1 0 26 EXP30833A 2.3G 6.0 4 31 0 0 27 Barricade 65WG .65 2 10 2 0 41 August Crabgrass % Cover Spurge Count Oxalis Count Treatment Rate (# a.i./A) July August 28 Barricade 65WG, Gallery 75WG .65 +.75 2 5 29 Dimension Monl5151 1EC .38 12 40 30 Dimension Monl5151 1EC .50 2 16 0 0 31 Pendimethalin 60WG 3.0 9 48 3 0 32 Dacthal 75WP 10.0 9 57 1 0 33 Scotts Fert. + Pend. 1.71G 2.6 3 27 1 0 9 30 NS NS L S D 005 - 42 - August 0 0 0 Postemergence Broadleaf Weed Control Study - 1991 N. E. Christians, R. G. Roe, and D. L. Struyk The objective of this study was to investigate the efficacy of several herbicides currently being evaluated as postemergence controls of broadleaf weeds in turf areas. The study was conducted on a site on the northern part of the Iowa State University campus on an old lawn area established with common Kentucky bluegrass. Individual plots measured 5 ft by 10 ft. They were arranged in a randomized, complete-block design with three replications. No irrigation was available at the site. However, the spring of 1991 was very wet and there was no moisture stress on the areas before the June 6, 1991, treatment date. There was an extended drought period during July and early August when the bluegrass on the area went into summer dormancy. The site had a good population of the following broadleaf weeds: dandelion ( officianale), white clover ( Trifoliumrepens), broadleaf plantain ( major), prostrate knotweed ( Polygonumaviculare), violet (Viola papilionacea), bindweed ( arvensis), and ground ivy ( Glechomahederacea). All treatments were applied with a backpack carbondioxide sprayer equipped with 8006 nozzles. The spray pressure was 20-25 psi. Treatments were applied with the equivalent of 3 gal water/1000 ft2. No phytotoxicity was observed on the Kentucky bluegrass. Weed counts were made on July 8 and August 21,1991. Tables 13 and 14 list the average number of weeds in a 5 ft by 10 ft plot. Clover infestation was heavy and percent cover evaluations for this species were estimated. Conditions were nearly perfect for weed control at the time of treatment and all materials tested provided excellent control of clover. Only Fluroxypur did not provide satisfactory dandelion control. Fluroxypur also appeared to be weak on plantain. The ground ivy population was highly variable on the plots, and this species was not observed in the control. Confront, the new non-phenoxy substitute from DowElanco, was very effective in this test as were the standards, Trimec and Turflon. - 43 - Table 13. Weed counts conducted on July 8, 1991. 3 CL cn O O O O O (SI o o o o o rj tN O O rH O rH cn 2 73 c 8 £b U 73 I £ & CO Q> cn 2 O > O O i S I r H O O o o o o o 73 8 1 cn O O LO O (N | 5 2 G 3 co rH o rH o O in cn 2 C g o u ofS DC 4S ’r 0 1 8 (3 £ HH CL O co (3 & HH CL O co HH HH CL in rH TP rH rH s o CO in CO (Q rH d o vD vn CO in CO in CL o in d q rH CO in CO in q HH Cl o co c 6 , < HH c X U rH Q G O o <5 Tt< in £ in rH Ph X VO X — £ ,-5 ° C L -j X frt X X w -H n X — «3 x .-; ^ a - .- ; x « J2 ^ P h rH J2 ^ PL rH 00 ON O rH £ -45- *5c/j5 *C55D «3 c l 2 £ ^ «n P h rH 2 .2 2 £ <3 N 'HH O in rH d rH + o o o N O rH rH ^ u 8M V.I £CD I— U u + *-• Q> *N CD QJ 6 s 00 00 u 00 *c *c 00 rH CL O C /l H H m co 8 ’cist e Table 14. K On Effects of Dithiopyr (Dimension) on the Rooting of Creeping Bentgrass N. E. Christians and R. G. Roe Dithiopyr (Dimension) is a new herbicide labeled for use on Kentucky bluegrass and other turf species in 1991. It functions both as a preemergence and early postemergence control of crabgrass. Trials with this compound on creeping bentgrass have been limited and little is known about the response of bentgrass to this compound at green-mowing height. The objectives of this study were to observe rooting responses and foliar phytotoxicity to dithiopyr on creeping bentgrass mowed at 3/16-in and maintained under putting green conditions. The turf was an 11-year-old stand of 'Penncross' creeping bentgrass established on a 1:1:1 (sand:soil:peat) soil mixture with a pH of 7.1. The area received 3 to 4 lb N/1000 ft2 in 0.2 lb increments as needed. No P or K was applied. Standard fungicide and insecticide treatments were made uniformly on all plots. Each plot measured 5 ft by 5 ft and the study was replicated three times. Treatments were applied on May 22, 1991, with a carbon-dioxide backpack sprayer (Table 15). The plots were observed for signs of visible treatment differences throughout the summer. At no time were there any signs of phytotoxicity. There was an initial positive response to the granular formulations of dithiopyr in some replications. This appeared to be due to a nutritional stimulation of the grass by the carrier. These responses were not consistent enough to be significant. Root samples were collected on June 19 and August 19 to a depth of 20 cm. The diameter of the cores was 2.54 cm and six cores were collected per plot. The samples were divided into four subsamples: 0-5, 5-10, 10-15, and 15-20 cm. All soil was washed from the root samples. Samples were dried, weighed, and ashed at 500°C. Root weights were reported as the difference between ashed and dry weights. Rooting varied by depth on both June 19 and August 19, but was not affected by herbicide treatment. Bensulide is a labeled compound for use on bentgrass greens and was used as a standard in this trial. Root weights of dithiopyr-treated bentgrass were generally similar to that of Bensulide-treated plots. This information combined with the lack of visible phytotoxicity would indicate that dithiopyr is likely safe for use on these varieties of creeping bentgrass maintained at green height. -46- rH O s O N rH OsV rH 4C T> l CO a 3 < to .£ rH o o g 13 s 13 to co h— 2 7 IN 1 o O d CO 2 O rH 00 C s rq rq CO d d d C QJ 13 > D cr a> <1> CO 2 as Os < > 04 o U w rH W rH ^4 & Oh Oh o o 2 2 2 4-» 5 4-» 4-* 0 5 U U o d rH 13 g »■J— 00 O' rH rH W rH 03 £ "O a> O h 03 4-»< w CD k & 2 Oh O h O o 3 C/3 2 2 c 4-* 4»* 0) C O 5 D w rH CO 2 & CL» Q. CX > U ^ o R i on £ Q CO t —1 c o s 4-* 1 s * -47- 1991 Sod Rooting Trial - 1 R. G. Roe and N. E. Christians The purpose of this study was to observe the effects of selected pesticides on establishment and rooting of Kentucky bluegrass (cv 'Ram I') sod. The test was conducted on a Nicolett (fine-loamy, mixed mesic, Aquic Hapludoll) soil with a pH of 6.9 and 2.3% organic matter. Individual treatment cells measured 6 ft by 8 ft and were randomized in a complete block design with three replications. Two separate trials were conducted, one irrigated and the other on a non-irrigated area. Treatments are listed in Table 16. The Kentucky bluegrass turf was cut at a 3/4-in depth and laid in the standard fashion on March 5. Sod pieces were transplanted into wooden frames, 6 frames per plot. The frames had 18-mesh fiberglass screen bottoms and were constructed of 1 in x 2 in pine boards with inside dimensions of 12 in x 12 in. Screw hooks were placed at each of the four comers for use as the point of attachment for the hydraulic lift apparatus. Check frames were pulled prior to treatment to ensure rooting. Pulling pressure exceeded 500 lbs and the sod in the area was assumed to be fully rooted at that time. Treatments were applied to the sod on May 2, 1991, with a backpack carbon-dioxide sprayer for the liquid materials and a shaker box for the granular materials (Table 16). Rooting was measured with a technique modified from King (King & Beard, 1969). The frames were lifted vertically with a hydraulic pump apparatus. Woven steel cords were attached to each of the four screw hooks on the frame and drawn to an apex over the center of the frame (Fig. 3). The force at the point of root breakage from the soil was measured by use of a hydraulic pressure gauge. Rooting measurements were used as an indication of sod establishment. The frames were lifted on July 9 (63 days past treatment) and September 5 (126 days past treatment). An analysis of variance was performed on all data. Because of the longer rooting period in this trial, root development was greater. Sod pulling pressure was 300 psi greater than in previous sod rooting studies. In nearly every case, pulling pressure exceeded the breaking point of the frames. There were no significant differences for irrigated and non-irrigated trials in sod pulling pressure at either the 63- or 126-day testing time (Tables 17 and 18). Root weights taken in July showed no significant difference under non-irrigated conditions. The irrigated trial showed a difference at the 0.16 level of significance. Ronstar 2G and Pendimethalin at the split application rate showed the smallest numerical reduction in root weight. Team 2G at 3 lb a.i./A and Balan 2.5G at 2 lb a.i./A showed the greatest numerical reduction in root weight. No noticeable differences in turf quality were visible after treatment. References 1. King, J. W. and J. P. Beard. 1969. Measuring rotting of sodded turf. Agronomy Journal 61:497-498. -48- Table 16. Treatments included in the 1991 rooting trial. Treatments Rate/plot 6 ft x 8 ft 1 Balan 2.5G: 2.0 lb a.i./A 40 G 2 Balan 2.5G: 2.0 + 2.0 lb a.i./A - 63-day split application 40 G + 40 G 3 Team 2G: 1.5 lb a.i./A 37.5 G 4 Team 2G: 3.0 lb a.i./A 75 G 5 Team 2G: 1.5 + 1.5 lb a.i./A -- 63-day split application 37.5 G + 37.5 G 6 Pendimethalin 60DG: 2.0 lb a.i./A 1.67 G 7 Pendimethalin 60DG: 1.5 + 1.5 lb a.i./A -63-day split application 1.25 G + 1.25 G 8 Ronstar 2G: 3.0 lb a.i./A 75 G 9 Check 1: Sample at time of first application (3 grids/plot) — 10 Check 2: Sample at 62 days after first appl. (3 grids/plot) Sample at 62 days after second appl. (3 grids/plot) -49- — JP £ ■4-» T3 CD -4-» G CD Ui ■4-t O s vO rH 00 £ m in vO vO CO K vO vO 00 vO d CO CO rq d ON rq d in TF d d vO O in rq 00 O rH K 00 vO vO vO £ d Üh d ON 00 O £ CO £ rH CO (N in 3 PU 00 hH co vO 2 Ph G Oh TJ QJ Ui 3cr CD G. o PU vO vO C C/2 /3 .2 *-G C TJ preemergence herbicides under irrigated conditions. C .2 G 3L O G 3, G Oh 3h v— ' O h r o C G £ G T n rH /3 vO £q h=Q < < < G G G G G 5 < Ò o g g vO vO PQ JP . ( j rq PQ rq co O rq G CD JO O rq G qj Ua 3 .2 TJ NCOO q 3 bo G T CO G G CD C/Ì *g Oh 3g \ Oh C .2 CD CD o Oh^ •JO G o Oh G G G H 2 G CD in vo CD JÛ 3 G oCO J vO rH d - -* G 4 4 -t C G CD CG 3 bp en * o< § >> a. T3 T3 CD JD 3 3 O h Oh oo TJ T3 CO CO o o C2 1 N in bo O CO co 9 i o d o N N O O N O C O in in co rq O rq o O d d d d CO 2 860 795 767 748 CO in 00 IN 742 CX 747 3 786 rq 742 Root weights from soil cores and the number of pounds (PSI) required to pull 1 ft2 frames from sod treated with preemergence herbicides under non-irrigated conditions. 4-4 SN Table 18. X 'bp *S CX a CX rH O N v IN V O v O IN C o 00 rH rH rH O IN IN vO O 00 vO IN IN IN 00 00 co 2 00 C .2 .2 03 "Eh CX c o X03 •u fH 3< CX 03 CX C /3 g) ■bpJO ! ' co *X 73 C +3 .2 03 73 C O vO 03 .2 CX v-" CX CX CX ^ CX 73 3L cx 03 CD c OJ o^ 03 03 « c -M CD O U 73 £ CX C /5 X 03 73 03 C O vO X O CO VO ! < 03 <43 35 X in rH u 4+a> 4 e/3 c/3 03 03 03 + in 03 73 73 rH o u 44qj -» -» V-t V CO CO VO vO -» -* .2 15 15 x 4—* o IS a> (N S s •3 £ 3 03 > co> cQ H CX CX 4 4 03 03 a> a> o "5,'a, CO 03 03 o CO CO rq Ut 4C03-» /3 2 c C Q o o CO -X C2 in vo 00 03 £ evO g vO LO c 03 S -51 - in u I >^o. 73 73 u 3 3 ON CO CO CX CX 73 73 o o 30 erri------------ - ------------- 30 ein 1991 Sod Rooting Trial - II R. G. Roe and N. E. Christians The purpose of this study was to observe the effects of selected pesticides on establishment and rooting of Kentucky bluegrass (cv. 'Majestic') sod. The test was conducted on a Nicolett (fine-loamy, mixed mesic, Aquic Hapludoll) soil with a pH of 6.9 and 2.3% organic matter. Individual treatment cells measured 5 ft by 5 ft and were randomized in a complete-block design with three replications. Water was applied as needed. The Kentucky bluegrass turf was cut at a 3/4-in depth on May 28, 1991, and laid in the standard fashion. Sod pieces were transplanted into wooden frames, 3 frames per plot. The frames had 18-mesh fiberglass screen bottoms and were constructed of 1 in x 2 in pine boards with inside dimensions of 12 in x 12 in. Screw hooks were placed at each of the four comers for use as the point of attachment for the hydraulic lift apparatus. Preemergence treatments were applied to the sod on May 30, 1991, with a backpack carbon-dioxide sprayer for the liquid materials and a shaker box for the granular materials. Postemergence treatments were applied on June 18 (Table 19). Rooting was measured with a technique modified from King (King & Beard, 1969). The frames were lifted vertically with a hydraulic pump apparatus (Fig. 3). Woven steel cords were attached to each of the four screw hooks on the frame and drawn to an apex over the center of the frame. The force at the point of root breakage from the soil was measured by use of a hydraulic pressure gauge. Rooting measurements were used as an indication of sod establishment. The frames were lifted 10, 20, and 30 days following treatment. There were no significant differences in sod pulling pressure at either the 10, 20, or 30 day testing time (Table 19). Mon 15152 0.25G showed the greatest reduction in pulling pressure at the 20th day following treatment. By the 30th day, the grass on plots treated with Ronstar 2G at 4 lb a.i./A and Mon 15151 1EC at 1 lb a.i./A had numerically greater pulling pressure than the other treatments. Pendimethalin 2G at 3 lb a.i./A showed the greatest reduction in rooting, but again, these differences were not significantly different at the 0.05 level of significance. No noticeable differences in turf quality were visible during the study. References 1. King, J. W. and J. P. Beard. 1969. Measuring rotting of sodded turf. Agronomy Journal 61:497-498. - 53 - Table 19. Pulling pressures required to pull sod frames from Kentucky bluegrass plots treated with preemergence herbicides. Treatment Rate (lb a.i./A) 10 days 20 days 30 days 1 Control — 290.0b 468.3 455.0 2 Mon 15151 1EC 0.5 276.6 371.6 428.3 3 Mon 15151 1EC 1.0 308.3 448.3 513.3 4 Mon 15152 .25G 0.25 283.3 366.6 444.0 5 Mon 15152 .25G 0.5 228.3 368.3 465.0 6 Mon 15151 1EC 0.5 (Post)c 320.0 433.3 375.0 7 Mon 15151 1EC 2.0 (Post) 285.0 493.3 453.0 8 Ronstar 2G 4.0 270.0 436.6 505.0 9 Exp 30742B 2.3G 6.0 250.0 420.0 380.0 10 Pendimethalin 2G 1.5 295.0 458.3 416.6 11 Pendimethalin 2G 3.0 291.6 456.6 336.6 NS NS NS Nonrestricted LSD(005) aApplied May 30, 1991. bPulling pressure psi. cPost treatments were applied after the 10-day treatment on June 18. -54- The Effect of Prograss on the Establishment of Cool-Season Turfgrasses J. B. Unruh and N. E. Christians Prograss (ethofumesate) is marketed as a postemergence control of annual bluegrass annua established in perennial ryegrass, creeping bentgrass (fairway height only), and Kentucky bluegrass turf on golf courses. The objective of this study was to observe the effects of Prograss on establishment of three cool-season turfgrass species seeded into sod previously killed with Roundup (glyphosate). Roundup was applied to 5 ft by 5 ft plots on August 16, 1991, at a rate of 2 lb a.i./A. Two weeks after Roundup application, plots were split into three 1.67 ft by 5 ft sub-plots, verticut, and seeded with the following grasses: Turfgrass Species Rate (lb/1000 ft2) 1. 'Glade' Kentucky bluegrass 2. 'Penncross' creeping bentgrass 3. 'Twilight' tall fescue 1.5 1.0 6.0 Prograss 50SC was applied three times. The first application was made at seeding, followed by a second application six weeks after emergence of tall fescue, bentgrass or bluegrass, and a final application was made twelve weeks after emergence. Prograss treatments and rates were as follows: Table 20. List of treatments for 1991 Prograss study. Treatment 1 Control Treatment 2 0.5 (lb a.i./A) (3 sequential applications) Treatment 3 0.38 (lb a.i./A) first application 0.50 (lb a.i./A) second application 0.75 (lb a.i./A) third application • Observations of percent cover were made at 28 days, 60 days, and 8 months after seeding (Table 21). Tall fescue stand was reduced by 20% and 10% by treatments 1 and 2, respectively. 'Penncross' creeping bentgrass was reduced by 39% for treatment 2, and 14% for treatment 3. Treatments 2 and 3, when applied to Kentucky bluegrass, yielded significant differences from the untreated control plots, but were not significantly different from each other. -55- Data from this study and an earlier study (1991 Iowa Turfgrass Research Report, p 37-38) show that seeding into a previously killed area produces much better results than seeding into bare soil. Table 21. The percent cover of three cool-season turfgrasses treated with Prograss 50SC. % Cover 28 days 60 days 8 Months Kentucky bluegrass 27 67 82 Creeping bentgrass 33 85 95 Tall fescue 38 90 92 Kentucky bluegrass 17 43 57 Creeping bentgrass 8 43 47 Tall fescue 37 82 82 Kentucky bluegrass 12 40 50 Creeping bentgrass 13 63 82 Tall fescue 33 80 78 Control Prograss (0.5 lb a.i./A) Prograss (0.38, 0.50, and 0.75 lb a.i./A) -56- The Efficacy of Ignite (HOE-39866) as a Non-selective Herbicide M. M. Mixdorf, D. L. Struyk, and N. E. Christians The objective of this study was to evaluate the initial and residual efficacy of Ignite (Hoe-39866) from American Hoechst Corporation as a non-selective herbicide for the control of Kentucky bluegrass. The study was conducted on an established Kentucky bluegrass turf composed of 25% each of 'Adelphi', 'Glade', 'Parade', and 'Rugby'. The soil on the site is a Nicolett (fine-loamy, mixed mesic, Aquic Hapludoll) with a pH of 6.9 and 2.3% organic matter. Individual plots measured 5 ft by 5 ft and the study was arranged in a randomized complete-block design in three replications. Treatments (Table 22) were applied on June 7, 1991, at a time when the grass was growing vigorously because of wet conditions during the month before treatment. All treatments were applied in the equivalent of 2 gal water/1000 ft2 at 25 psi with a backpack carbondioxide sprayer equipped with 8006 nozzles. After the June 7 application, 12 weekly ratings were made on a percent damage scale where 0 = no damage and 100% = complete kill. The study was concluded on August 30, 1991. The best control obtained with Ignite was 90% at the 1.9 lb a.i./A rate, 3 weeks after treatment (Table 22). After the third week, grass in plots treated with Ignite, a contact herbicide, began to recover from the rhizomes. Glyphosate (Roundup), which is a systemic herbicide, maintained nearly complete control during the entire 12 weeks of the study. The addition of Garlon, a postemergence broadleaf control, to the Ignite did not improve the control of Kentucky bluegrass beyond that obtained with Ignite alone. Ignite may have some use as a quick, 'knock down' treatment for grasses, but extended control of rhizomatous grasses requires a systemic control. -57- Table 22. o in CO ON o rH rq rH r o o IN. in in 00 ON rq CO rH o rH o o 00 rH rq rq rq ON o s—* -* £ CD g »—i -* nS <£S flS J2 00 o — 1 £ CD .S *■-» 00 CM r-H CO 00 O IN £ o co o rq o rH o O in tN vO 00 < ns £ a> IS o in rH O rq o CO o rq O rq + in rH c 4C-»D c j—i H o 4u-» vO vO vO s ON CO g ON CO 1 ON co pa O DC 1 pa O c o u X w o I rH . cn IN. o Ö CO CO X. rH o 4— 4 cu c C/5 S2 .2 o II rH £ II u /3 £ rH C 03 C U T3 T3 C/ 3 03 C cu 03 ' S JC o T3 CU CD M—1 V o 034 M-l cu rB '03S *c H + cu 32 'S ‘3 C cu B '03S *c H + (U 32 'S '3 ca <33 s s s CO m vO <33 3 S CU c/j CO nj X) u Evaluation of Fungicides for Control of Dollar Spot in 'Emerald' Bentgrass - 1991 M. L. Gleason Trials were conducted on the turfgrass research plots at the Horticulture Research Station of Iowa State University near Ames, Iowa. Fungicides were applied to Emerald bentgrass maintained at a 5/32-in cutting height, using a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal/1000 ft2. The experimental design was a randomized complete-block with four replications. All plots measured 4 ft x 5 ft. The entire plot was inoculated with rye grain infested with the dollar spot pathogen on May 30. Fungicide applications began on June 5 and continued at recommended intervals (14, 21, or 28 days) until July 29. The number of dollar spot infection centers per plot was counted on June 19, July 4 and 17, and August 1. Weather was relatively wet until mid-June, then unusually dry through the end of the test period. Dollar spot symptoms appeared on June 16. Disease pressure was moderate on June 19 and August 1, and severe on July 4 and July 17. Almost all treatments suppressed dollar spot significantly (DMRT, p>0.05) better than the check (unsprayed) treatment on all rating dates (Table 26). The combination of ProStar 70WG and Cyproconazole 40WG produced an enhanced green color on plots on August 1. -66- Ln o rH G 03 c c H 2 U PC G vjo ° N g iifn c u ° m o rq in cq in rq in d K d K d N N ° N O co N o O o o rq rq o < $ PL, On pp c c 03 03 o \D rq o £ £ o N T> T> > > T3 u 0» JC N g ^ U LD in rq in rq O < + Sx Sx £ in + £ in - 67- + pl n ^ o £ in pl n k >< + PL ^ Sx £ in + Q o Q V O a In >< + Cl 2 U c hJ PL N o c 0.00 c 0.00 d 0.00 e 0.00 c 4.0 oz N O ngo/Vorlan WSB Premix . ! 03 O N O on Table 26. 14 0.25 d 0.00 e 0.00 c 14 0.43 2.0 oz s-i 0J ngo/Vorlan WSB Premix Evaluation of fungicides for control of dollar spot on 'Emerald' bentgrass, 1991. 0.00 c U 73 73 73 73 73 73 73 73 CD CD o> CD o o O o o o d d d >> oo 3 d O N rH CD C a cd o o o cd o o d cd o o o cd o o d 73 O o d CD O o d cd o o d o o d w <2 w rH 3 , u ^ w ¡2 rH 3 ^ ^ Urea (45% N) o o d d cd 77.25 b d o o o cd 108.50 b o o cd 46.50 b o in cd 2.00 c O o d cd 0.00 c O o d 1.00 d CD CD O o d 0.00 e d in rq rH cd 0.00 c 3 O O d o o cd 1.0 oz 0.89 lb 73 o o o Banner 1.1EC + Co. Ro. N (28% N) Number of infection centers per plot1 CD & O a O < O o o d H3 u d) IN a<£! CD O .i_J ¿ h rH N O NO d N O rq N O o rH rH N O O rq N O o N O o NO ON ON rq < PQ o o CD Q hJ h J c0> oo in e Ph Ph £ 00 c3 o o £ 0c3 0c3 c0/ i bO bJD 73 73 O C c a o o a a 3 Uh PP > > Q H lp Ph C . CL D £ c C 35 C / o 3 Q rq < rq < 2 O 2 O cu IN o o IN iIN 3 3 3 2 CO * CO CO 00 2 CO 00 2 CO 00 2 CO -68- a> o N U C03 u o d w o c o In Sh u Oh *H 03 CD c <£ U c o , £ NO in d rH ^ 2 ut + Oh 03 U ^ U 03 u> CO Ph <: o vO VO 00 CO X Pi PP CD £ o CO o fH Jc S O q rH Jp)cDS I vN O O JcDS c co o co JcDS O O CM IN vO d O O XCS c o O co O 0.33 a O CS O O 0.00 b 3 g C O O CO O 0.00 a g o 0.00 b VO CM cS CL) O c O G co cS 3CD C s: C c J-i H U > > 7 N N O O in 2 oz N O CM O X co co Fungo/Vorlan WSB Premix 3 °rH P i N O CM 6 oz CL) O CM CM CM l-l Q>ts CP<Ü 00 00 oo CO C0 pp ON ip PL, pu tn i oX £ + co tn i oX £ + co ç/5.« tn X .L o X o £ 4- a + co CO -71 - pp pp C/J VL pp 14 G C/3 Ë & H3 Broadway 4.42AS Table 27. Evaluation of fungicides for control of brown patch in bentgrass, 1991. C /3 es X P> X P> X cd cd In vO d o o o q O o vq In vq IN CO cq rH rH rH rH rH rH x X X cd X cd X cd CO CO ri CO rH X 3 CO CO r4 CO CO csi rJH rH rH Tt rH rH cd u o o d 3 CO CO CO X o q rH Tt rH cd cd IN vO cd cd cd cd cd CO CO CD rq D o 4—* cd oo X rH N O N O vO N O q d rH N O N O vO N O CM cd cd u cd o> X CO CO d cd X O X IN X ri IN vO d co q vq rH rH IN vO d X cd cd X cd X cd X cd X cd Xcd CO CO ri IN vO co IN vO ri o o ri co co co IN vO csi IN vq X ^ rH IX o X bo co c D £ tin pp s 00 o bo c 3 Ph pp X co £ s 00 c cd O • CO bo o C a 3 PP Q X CO £ C cd CO o 3 Q pp u £ o £ o o rH in rH u m cd cn < 2 2 IN In 4c-d 4 CO o 14 PP rH rH CM X cd 4-4 CO < U 2 + 2 X 00 rH in X X X1 U CO < 1 CO < 1 CO < July 26 O O o O O O July 12 43 o o d 4> o o d 43 o o d u CJ 40 CO CO d June 15 40 CJ 03 O 4^ t-h June 7 40 June 27 O O © 03 hO co CO d CJ 03 O O 03 O O CO 03 03 03 03 co O C 3 ro H o 03 O O o 03 O o o 43 43 o o d o o d X» o o d o o d o o d CJ o o d CJ O O d CJ 40 CO co d CJ 40 CO CO d CJ o o d CJ 40 CO CO CO CO rH d r-H 40 40 40 40 q 03 O O CO 03 CO co CO CJ 03 03 IN NO cq CJ 03 O q CJ 03 O O 40 r-H rH 03 IN NO o o d 43 03 IN NO d 43 o o d 4> 03 CO CO d CJ o o d CJ rO 03 IN NO d CJ 40 CO CO d •8 IN NO d CJ o o d CJ o o d CJ 03 40 40 CJ 4> CO CO CJ 03 O q CJ 03 IN NO d rH d -2 03 *2 03 40 CJ 03 40 in in CO CO CO CJ 03 IN NO CO rH rH r-H r-H rH 40 40 40 40 403> 03 O co q 03 03 03 (3 CO CO O 03 o o d hQ CJ 03 O 03 O O d 40 CJ 03 O 03 03 o o d co rH cq C ^ ^ 8f3 *C to n c CL> .S 03 N O 00 ca. N rH O 03 O 4-t 9 o 'b S M_ Oh o cn Oh ^ 03 o Treatment rH NO NO 1 U cn < 00 9 NO NO 1 U cn < 00 s VO NO 1 u cn < in in S3 4NO NO NO • U cn < NO U cn < cn 73 a) c © c 0i cn Ph IN 00 o ^ «3 o q 2 CP + + IN cq •ri C o CD 03 03 + CQ CP CP £ o Tf NO NO 00 co 1 X vO rH rH NO O1 X Pi CP £ in cq ^ in in i g x ¡N, + dl 03 II11 2 c H £ 3 T3i O O Ui Tp3 to •^ T3 ^ Q-> 03 O cq cq *cj ON 2 *-< on $ ® ^ •—< t , U-l T3 o o O M-1 cn C IN t> ii ii O C vu V c 03 45 U Evaluation of Fungicides for Control of Snow Molds on Creeping Bentgrass, 1990-1991 M. L. Gleason The trial was conducted on a creeping bentgrass green (Hole #4) at the Waverly Municipal Golf Course, Waverly, Iowa. This green had a history of outbreaks of gray and pink snow molds in most of the last 10 years. The experimental design was a randomized completeblock with 4 replications. All plots measured 5 ft x 5 ft. Fungicides were applied on November 13, 1990, using a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal/1000 ft2. Immediately after application of fungicides, the entire plot was covered with two layers of Curlex High-Velocity excelsior mats (American Excelsior Co., St. Paul, MN). The mats were fixed in place with wire stakes. The purpose of the mats was to simulate snow cover and provide favorable conditions for the development of snow mold even in the absence of snow cover (W. Stienstra, Department of Plant Pathology, University of Minnesota, personal communication). Snow cover persisted on the green from December 5, 1990, until March 1, 1991. Mats were removed on March 6. On that date, symptoms of gray and pink snow mold were abundant at many sites on the golf course. Snow mold development on untreated check plots was moderate (Table 28). Symptoms of both gray and pink snow mold were evident in these plots. All fungicide treatments gave significantly better control of snow mold than the untreated check; 9 of 11 fungicide treatments were free of snow mold damage. None of the fungicide treatments was significantly different from the others in disease suppression. Treatments that had incorporated green paint were perceptibly greener in color than other treatments. No phytotoxicity symptoms were observed. Because snow mold occurred naturally at Waverly Municipal Golf Course in 1990-91, no conclusion could be drawn about the effect of excelsior mats on disease development. However, in winters with less than three months of snow cover (a common occurrence in Iowa), the mats may provide temperature and moisture conditions favorable for snow mold development. -74- Table 28. Company Evaluation of fungicides for control of snow mold in creeping bentgrass at Waverly Municipal Golf Course, Waverly, Iowa, 1990-91. Treatment Rate per 1000 ft2 Percentage of Plot with Symptoms3 17.5 a Check ISK Biotech Daconil 2787 16 oz 0b ISK Biotech Daconil 2787 + green latex paint (67019) 16 oz 1 gal/40 gal HzO 0b ISK Biotech ASC 66791 8 oz 0b ISK Biotech ASC 66791 + green latex paint (67019) 8 oz 1 gal/40 gal H20 0b DowElanco Rubigan IAS 8 oz 0.5 b Nor-AM NA249 70WDG (coformulation) 1.25 oz a.i. 0b Terra Banner 1.1EC 4 oz 0b Terra Banner 1.1EC + Plex 4 oz 0.25% 0b Terra Rubigan IAS + Plex 8 oz 0.25% 0.5 b Grace-Sierra Calo-Gran 8 lb 0b O. M. Scott S-2521 2.6 Kg 0b 3Means of 4 replications. Means followed by the same letter are not significantly different (DMRT, P=0.05). c - 75- Evaluation of Rubigan-Cutless Combinations for Control of Dollar Spot in Creeping Bentgrass - 1991 M. L. Gleason Trials were conducted at Veenker Golf Course on the Iowa State University campus, Ames, Iowa. Fungicides were applied to creeping bentgrass maintained at a 5/32-in cutting height, using a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal/1000 ft2. The experimental design was a randomized complete-block with four replications. Treated plots were alternated with untreated plots, so that treated plots did not adjoin each other. All plots measured 4 ft x 5 ft. The entire plot was inoculated with rye grain infested with the dollar spot pathogen on May 30. Fungicide applications began on June 6 and were repeated on July 3 and July 29. The number of dollar spot infection centers per plot was counted on June 5, June 21, July 2, and July 17. Weather was relatively wet until mid-June, then unusually dry through the end of the test period. Dollar spot symptoms were present at low levels on June 6; disease pressure was moderate on June 21 and severe on July 2 and July 17. Rubigan suppressed dollar spot significantly (DMRT, p>0.05) better than the check (unsprayed) treatment at all concentrations on June 21 and July 17 (Table 29). All treatments were relatively ineffective on July 2, which was approximately 4 weeks after fungicides were applied. A visual examination of the data suggests that increasing the rate of Cutless in the Rubigan-Cutless combination did not enhance disease suppression. Further analysis of the Rubigan-Cutless interaction indicated that the interaction was not statistically significant (data not shown). - 76- Table 29. Evaluation of Rubigan-Cutless combinations for control of dollar spot in creeping bentgrass, 1991. Number of infection centers per plot3 Rate per 1000 ft2 Timing (days) Check — Rubigan IAS June 5 June 21 July 2 July 17 — 7.00 a 91.50 a 145.00 a 173.75 a 0.5 oz 28 2.50 a 38.75 bed 96.25 ab 100.75 be Rubigan IAS 1.0 oz 28 5.50 a 5.75 de 72.50 b 48.25 ede Rubigan IAS 1.5 oz 28 7.25 a 1.50 e 51.00 b 20.75 de Cutless 50WP 0.125 lb a.i./A 28 3.50 a 47.50 be 94.75 ab 107.50 be Cutless 50WP 0.188 lb a.i./A 28 3.50 a 67.75 ab 112.75 ab 146.75 ab Cutless 50WP 0.25 lb a.i./A 28 2.25 a 44.00 be 91.50 ab 93.50 be Rubigan IAS + Cutless 50WP 0.5 oz 0.125 lb a.i./A 28 6.75 a 25.75 ede 92.00 ab 82.75 cd Rubigan IAS + Cutless 50WP 1.0 oz 0.125 lb a.i./A 28 4.50 a 7.25 de 93.25 ab 55.75 ede Rugigan IAS + Cutless 50WP 1.5 oz 0.125 lb a.i./A 28 3.00 a 0.00 e 58.25 b 7.50 c Rubigan IAS + Cutless 50WP 0.5 oz 0.188 lb a.i./A 28 4.50 a 8.25 de 66.25 b 55.25 ede Rubigan IAS + Cutless 50WP 1.0 oz 0.188 lb a.i./A 28 5.75 a 7.50 de 103.75 ab 60.75 ede Rubigan IAS + Cutless 50WP 1.5 oz 0.188 lb a.i./A 28 4.25 a 1.50 e 75.75 b 12.75 e Rubigan IAS + Cutless 50WP 0.5 oz 0.25 lb a.i./A 28 5.25 a 13.25 ede 81.50 b 69.25 ede Rubigan IAS + Cutless 50WP 1.0 oz 0.25 lb a.i./A 28 3.50 a 7.75 de 87.50 ab 52.50 ede Rubigan IAS + Cutless 50WP 1.5 oz 0.25 lb a.i./A 28 2.50 a 1.50 c 72.50 b 11.25 e Treatment an = 4. Means followed by the same letter do not differ significantly (DMRT, p>0.05). -77- Natural Organic Trial M. L. Agnew and S. M. Berkenbosch A natural organic nitrogen (N) trial was established in 1989 on a four-year-old 'Park' Kentucky bluegrass ( P o a p r a t e n s i s ) stand. The grass was mowed weekly with clipp removed, dried, and weights recorded. Irrigation was applied at a rate of 1 in of water/week. In 1991, rainfall was excessive from May through June. The purpose of this study was to compare nine natural organic fertilizers to urea. Treatments included BioTurf 10-4-4, Sustane medium grade 5-2-4, Sustane fine grade 5-2-4, ISU experimental (10% N), Milorganite 6-2-0, Natures Preference 5-3-5, Ringer 10-2-6, Ringer 6-1-3, Howe 5-2-5 (added in 1990), Urea 46-0-0, and a control. All fertilizers were applied at 1 lb N/1000 ft2 on May 15, June 15, August 15, and September 15, 1989. This study was replicated three times in a randomized complete-block design. Individual plot dimensions are 5 ft by 10 ft. Data collected during the summer of 1991 included visual quality and clipping yields. All plots were rated weekly on a visual scale of 9 to 1. A rating of 9 is equal to a dark-green, dense turf, whereas a rating of 1 is equal to a straw-brown turfgrass stand. A rating of 6.0 was used as the minimum acceptable level of quality. Clipping yields were collected on a weekly basis or when enough grass was present to collect. Clippings were collected by removing all the leaf tissue above 2 in within a 21 in by 10 ft area (17.5 ft2) down the center of each plot. Clippings were placed in paper sacks and dried. Weights were recorded as grams per 17.5 ft2. Visual quality ratings are presented in Tables 30 and 31. Urea had the overall highest quality while the control and Natures Preference had the lowest quality rating. Sustane fine had the best overall quality rating of the natural organic fertilizers. Following the May application, only plots treated with Natures Preference consistently had quality ratings at less than an acceptable level. Clipping yield data is presented in Tables 32 and 33. Plots fertilized with urea produced the most clippings. Unfertilized control and plots fertilized with Natures Preference produced the least amount of clippings. For other fertilizers, Ringer products, Sustane fine, and ISU Experimental produced high quantities of clippings; Milorganite and BioTurf produced moderate amounts of clippings; and Sustane medium and Howe 5-2-5 produced the least amount of clippings. - 78 - Table 30. The influence of natural organic fertilizer sources on visual quality from April 16 to June 24, 1991. June May April Fertilizer Source 16 26 2 13 21 28 3 10 17 24 Control 2.0 3.3 3.7 5.3 4.7 5.0 5.0 5.3 5.0 5.0 Milorganite 4.0 5.3 6.3 7.0 6.0 6.3 6.7 6.7 6.3 6.0 Restore 10-2-6 4.3 5.7 7.0 7.0 7.0 7.3 7.3 6.7 6.3 7.0 Restore 6-1-3 4.0 5.3 6.3 6.7 6.3 6.7 7.0 6.3 6.0 6.0 Sustane (Fine) 4.0 5.3 6.3 6.7 7.7 7.0 7.7 6.7 7.0 7.7 Sustane (Medium) 3.7 4.3 5.7 6.0 6.3 6.3 6.7 6.0 5.7 7.0 Natures Preference 2.0 3.3 4.0 5.3 5.3 5.3 6.3 6.0 5.3 6.0 ISU Experimental 5.0 6.3 7.3 7.3 6.7 7.0 7.7 7.0 6.7 6.7 Howe 3.0 4.7 5.3 6.3 6.7 6.3 6.7 6.7 6.0 6.7 BioTurf 6.0 7.0 8.0 8.0 7.7 7.7 8.0 7.0 7.0 7.3 Urea 6.0 6.3 7.0 7.0 8.0 8.0 8.0 7.0 7.0 8.0 LSDjoosj 1.5 1.3 1.2 1.0 0.8 0.8 0.8 0.7 0.6 0.6 - 79- J-l CD I tj Table 31. The influence of natural organic fertilizer sources on visual quality from July 1 to October 8, 1991. O CO if ) P4 CD Ui -» #3 CD *3 C CD E, £ CD CD CJ C u CD CD M-l 2 CL, CD ccd c a 3 4-* C/i iS CD 3 3 3 CD CD z cd cCD 4-4 g •c CD CX w CD 3 £ H o D O CD X 80 CD (0 2 P CO P Table 32. The influence of natural organic fertilizer sources on clipping yields from May 3 to June 24, 1991. CM C 0) a CO 00 CM 03 CM CO CO QJ Ua u a o cr> N PL. 15 NO NÒ rH CO in cu o IN 00 ON rH rH CO c> 0 4-^ Uh rH CO 0) co ON rq rH CO rq $ o IN cd ON NÒ rH O On 00 On ON rH rH o S 00 rH ri Ö o IN rH 00 rH 0> u Ui p o CO 14 0N 1 > J-4 c/a £c 03 J-4 bo C/3 03 T(U 3 d o O h C U U t c1u 4 03 Control 3) o < CD rH SN Table 37. 4-4 CD rq d rq rq Os* rH SN The effects of fertilizer sources on clipping yields(a) on 'Park' Kentucky bluegrass. CD rH in rH ON VO rH CD 6.2 Cc/5 03 o in © O CD X CD T3 3 *>> bo -g ’a* u s The Evaluation of Nitrogen Sources on the Quality of Bentgrass Greens M. L. Agnew and S. M. Berkenbosch In the spring of 1991 a study was established to evaluate the performance of 13 granular nitrogen fertilizer sources. The treatments are listed in Table 38. The treatments were applied at a 0.5 lb N/1000 ft2 on May 25 and June 26 to a 'Penncross' creeping bentgrass/Poa annua green. The testing area was located at the Hyperion Field Club, Johnston, Iowa. The plot consisted of a randomized complete-block design replicated three times. The plots were mowed daily and irrigated as needed. Visual quality data was collected weekly. Visual quality ratings were based on a scale of 9 to 1 with 9 = dense dark green turf, 6 = acceptable quality, and 1 straw brown turf (Table 38). The fertilizers containing higher soluble nitrogen (Coron, Country Club, Country Club + NIAD, Scotts + Minors, and Scotts + Manganese) had consistent average visual quality ratings above 6.0, dipping below 6.0 one or two times. Scotts + Manganese had the highest overall ratings and remained deep green in color during the entire 1991 testing season. The second most noticeable dark green turf was obtained by using Scotts + Minors. Both fertilizers maintained a 7.0 or above rating for most of the 1991 testing season. The rest of the fertilizers used were slow-release nitrogen sources and showed ratings of 5.0 to 6.0 the first part of June. From mid-July through October the slow-release fertilizers showed turf with ratings of at least 6.0 or above. - 88 - o o 00 00 00 K 00 CO IN IN IN IN o IN 00 so CO 00 o rq o CO o CO 00 00 o IN co IN co 00 O Table 38. The comparison of fertilizer sources on the visual quality*3’ of bentgrass. 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O NÒ en tx' tx NÒ m P 00 m tx o oô en tx en NÒ o NÒ o tx en NÒ tx tx o tx O IX tx NÒ o NÒ o NÒ O tx! en NÒ tx NÒ en NÒ en NÒ o NÒ tx NÒ tx NÒ tx NÒ en NÒ oo < o £ o £ >« Z o Z £ >< Z 0 £ >< Z (fi >< Z (fi >< 0 >< Z O > £ >< o Z 0 Z $ > o Z Z ch a» 0 en o >< £ >< $ >< Z £ >< Z Z 0 $ 8 >< Z 0 S S >* en 0) 3 o >x «O S m . >x A-J 13 CL Ë O U cr 13 3 C/3 > ¿5 c B B 0 U Z 0 Z Z Z $ >< o Z 0 Z 0 o Z $ >H Z 0 > Z C/5 tj >< (NJ (X Ò Ò (NJ 1 O CNJ Ò Ü B Z 0 8 0 Ü 'c C0 0 8 0 Ü c C0 M) £ Dò $ Dò Ü5 Dò ÜB Dò 0 0 yj 0 0 o Z "cO a; U H Ö 3 n i f-H V u N :£ tî D CL co C0 Z D Z D C0 c0 Z Z D D D Q S D Q Dû D Q CD D Q S -93- "e C0 te u 1 u JC § te u JD Ü a¿ 'c C0 te u jd 1 en en en N¿ N0 N¿ NO B o £ 0 £ 0 B ÜB Dò Üü Dò üü Dò o ÜÜ Dò CL 'JB u 0) 3 Cü CL CL 'Je JC J3 £ S u 0) u 3 Cl 'Je u eu J3 S Table 41. Clipping height MURP Studies M. L. Agnew and S. M. Berkenbosch In the spring of 1990 a study was established in cooperation with O. M. Scott & Sons Company to compare the effects of four nitrogen formulations on a four-year-old stand of 'Ram I' Kentucky bluegrass. Individual plots measured 3 ft x 10 ft and the treatments were replicated 3 times in a randomized complete-block design. The plots were mowed weekly with one mower pass and all leaf tissue above 1 1/2-in collected. Irrigation was added to reduce plant stress. Nitrogen fertilizers used in this study include: three methylene urea formulations (39-0-0, 41-0-0, and 42-0-0) and urea (46-0-0). The fertilizers were applied at a rate of 1 lb N/1000 ft2 on May 10, June 20, and August 10. Data collected included fresh clipping weight and visual quality rating. Clippings were collected each week or when growth warranted clipping removal. Clippings were collected with a Toro rotary mower and placed in bags. Fresh weights were recorded immediately after mowing. Visual quality ratings were collected weekly prior to clipping removal. Ratings are based on a scale of 9 to 1: 9 = a dark green turfgrass stand, 6 = a minimum acceptable level, and 1 = dead, straw brown turf. Spring green-up data is presented in Table 42. In April, plots treated with 46-0-0 and 42-0-0 greened up quicker than other plots. Following each fertilizer treatment, 46-0-0 demonstrated higher quality (Tables 42 and 43). Interestingly, this quality did not diminish over time. Plots treated with 42-0-0 and 41-0-0 provided the best quality among the methylene ureas. The high quality ratings of 46-0-0 can be explained in part by the clipping data. Plots treated with 46-0-0 consistently had higher clipping yields (Tables 44 and 45). For example, plots treated with 46-0-0 produced in excess of 2 times the clippings of plots treated with 42-0-0. This type of growth could create problems associated with everyday maintenance, such as mowing and disease activity. -95- ro j* » 3 IN IN o no vd in 00 o IN ro no vd in ro IN o o o u 3 < 2 h CO rH O C/5 ro o o in vd 00 vd d bJO C G 14 ’■G ro 4-» CO IN IN O IN o o IN IN 00 in q rH 13 g cr 13 G C/3 rH rq ro rH rq | *G Oh no o 00 IN vO d 0.7 in o IN rq O o O VO vd vd vd 00 in d IN ro in in IN rq rq IN 00 5.0 IN vd 6.3 IN 7.0 O IN 7.3 00 rq o o 00 IN ro d rq o ro ro vd rq rH rH ro rq o o NO in rH d < O rH ro ro 1-4 Table 42. 00 o in 00 May The influence of methylene urea sources on visual quality ratings(a) form April 16 to July 30, 1991. a in N *■£ Pt , -i o o 5 O i o o o cb o rH afv vd ro u < uL> G 0» G CG u Q CO hJ 4-4 C /2 So 3 < rq ro rH IN G ro 4-4 c o rq o O o o NO 00 IN av* NO d ro o ro o o NO NO IN NO 00 in d o 00 o> X H m o o G O C/5 < L> u V4 G O (A 03 K G G a> X 4-* 0) £ • S H - 96 - U a> o *■£ 6 a> to 3 t o1 o o1 o 3 o rH av NO ro / _„ in o o o H 4-4 c o o CO hJ u (a)Visual quality is based on a scale of 9 to 1: 9 = dense, dark green turf, 6 = minimum acceptable quality, and 1 = straw brown turfgrass sod. o CM CM rH CSI CO c a CM NO H CM NO CM NO NO CO im d rH s CO NO CO o CO CO 2 CM ON CO 00 CO S3 ON ON o (M in NO tN rH csj in CO in im 3 vO d rH rH ON d rH in NO in ^ VO CM ON* CM CM d CM o NO ON CM ON CO in CO CM in! o 00 ON ON 00 00 o CO CO 00 NO CM 3 In. in ON vO 00 CM d co rH CO ON rH U rH o J-i rH rH NO 00 CM rH rH rH rH 3 C /5 2 3 "5 , to rH in! NO o in CO 00 rH c *Oh CL 00 CM n3 a CM CO IN. ON in in 00 NO CO in! d CO CM CO NO in in co rH rH in ON CM rH 00 in! CO co in! CM CO rH o d cm tN C) rH CM IN. ON 00 CO o rH CO rH CO C in CM O rH in NO CM c o C/3 QJ £ CM csj NO CO rH ON in a; N 3 Ph O 6 9 im NO CO in ON rH c a> D qi! IN. CM IN. CO in ' o o o o 34H © -* 6I 6 6 c Q rH ON M b o cn CO u t—3 O NO d CM CM CM 00 00 rH rH ON d CM O d CM oi oI rH 00 in! CO vO CM On ON 3 g C L> i-i Table 44. 00 vO NO C CL» X H CO d CO tN rH rH CM CM CM rH rH CO NO NO in CM o o o 6 6 6 4-» ON rH CM L-i in a> I H - 97- d> N tJ a> Ph S3 i rH ON NO CO o u c o u 8 -J (a)Fresh weights of clippings. The influence of methylene sources on clipping yields'3’ from May 7 to June 24, 1991. ON IN, CO 00 Ti CM rH rH CL a> co cm CM VO d NO £ O) CO In ! rH NO In! 00 Plant and Soil Response to Nitrogen Fertilizer Sources M. L. Agnew, N. E. Christians, and J. N. Ryan Turfgrass managers have several nitrogen sources from which to choose. Quick-release sources provide fast green-up and are relatively inexpensive. Slow-release sources extend the feeding time by slowing the release rate of available nitrogen. Some advantages claimed from using slow-release sources are reduced chance of fertilizer bum, less volatilization, and less leaching. With the environmental concerns currently surrounding fertilizers and the leaching of nitrates into the groundwater, it is important to understand the possible differences among nitrogen sources as they pertain to nitrogen use efficiency and the movement of nitrates in the soil. This study will evaluate 8 fertilizer sources as to their effects on plant growth and nitrogen content in plant tissue. In addition, the movement of nitrates through the soil will be monitored. The study was initiated in the spring of 1991 on an established turf of 'Glade' Kentucky bluegrass mowed at 2 in. All treatments were applied at a rate of 1 lb N/1000 ft2 on May 2, June 10, August 15, and September 15, 1991. The study was replicated three times in a randomized complete-block design. Individual plots measured 5 ft by 9 ft. The following is a list of the treatments: (1) (2) ( 3) (4 ) (5 ) (6) (7 ) (8) (9 ) Coron 28-0-0 Nutralene 40-0-0 Sulfur-coated Urea 37-0-0 Urea 46-0-0 Ringer Lawn Restore 10-2-6 Ureaform 38-0-0 N-Sure 28-0-0 ISU Experimental 10-1-0 Control -- no fertilizer Measurements of plant growth included weekly observations of visual quality, clipping yields, and chlorophyll content. Plant development was monitored by measuring plant density, thatch depth, thatch organic matter content, rhizome weights, and root distribution. These measurementss were taken prior to the first treatment, in the middle of summer, and at the end of the season. Nitrogen content in leaf tissue was measured weekly and nitrate content in the soil at several different depths up to 3 ft were taken initially, in midsummer, and at the end of the season. Quality data is presented in Tables 46 and 47. All fertilizer sources provided acceptable quality. However, urea-treated plots consistently had the darkest green color. Dried clipping weights are presented in Tables 48 and 49. Urea-treated plots produced a high of 414.9 g/17.5 ft2/season whereas Nutralene-treated plots produced a low of only 312.8 g/17.5 ft2/season. Only the non-treated control produced less clippings. - 98 - Total chlorophyll content data is presented in Tables 50 and 51. Total chlorophyll is a quantitative measure of plant color. Fertilizers that contained water-soluble nitrogen (urea, N-Sure, Coron) tended to have higher chlorophyll content. Root data is presented in Table 52. All fertilizer sources had less total root growth than the non-fertilized control. Urea-treated plants had 46% less roots than the control, while the Coron-treated plants had only 21% less roots than the control. Soil nitrate data is presented in Tables 53 and 54. There were no differences between fertilizer treatments in 1991. This study will be carried on through 1992. -99- Table 46. The effects of fertilizer source on the visual quality00 of Kentucky bluegrass during 1991. June May July Fertilizer Source 15 22 28 3 11 18 25 2 15 30 Coron 28-0-0 8.0 7.7 8.7 8.3 8.7 8.3 8.7 7.3 8.0 7.3 Nutralene 40-0-0 6.7 7.0 7.7 7.7 7.3 8.0 7.7 8.0 8.3 7.3 Sulfur Coated Urea 37-0-0 7.0 7.0 7.7 7.7 7.7 8.7 8.7 8.3 8.3 8.3 Urea 46-0-0 8.7 9.0 9.0 9.0 9.0 8.7 8.7 8.7 8.0 7.7 Ringer Restore 10-2-6 6.3 7.3 8.0 8.7 7.7 8.7 8.7 8.3 8.7 8.3 Ureaform 38-0-0 6.7 6.7 7.3 7.3 6.7 7.3 7.0 7.0 7.7 6.7 N-Sure 28-0-0 8.0 7.7 8.3 8.3 8.3 8.3 8.3 7.3 8.0 6.7 Com Gluten Meal 10-1-0 6.0 6.3 8.0 8.7 7.7 8.0 8.0 8.7 9.0 8.3 Control —no fertilizer 5.7 6.0 6.3 7.3 6.0 6.0 6.3 6.0 6.7 5.7 LSD joos) 1.3 1.1 NS 1.0 0.8 0.8 0.8 1.0 1.2 1.0 Table 47. The effects of fertilizer source on the visual quality*0 of Kentucky bluegrass during 1991. August September October Fertilizer Source 12 21 4 10 17 24 30 8 Coron 28-0-0 7.0 8.7 8.3 7.7 8.0 8.0 8.0 8.7 Nutralene 40-0-0 7.3 7.3 7.7 8.0 7.7 8.0 8.3 9.0 Sulfur Coated Urea 37-0-0 8.3 8.3 8.0 8.0 8.0 8.0 8.0 8.3 Urea 46-0-0 7.0 9.0 9.0 9.0 8.7 8.7 8.7 9.0 Ringer Restore 10-2-6 7.3 7.7 7.3 8.0 7.7 7.3 7.3 7.7 Ureaform 38-0-0 7.3 7.3 7.3 7.0 7.3 7.0 7.3 7.3 N-Sure 28-0-0 7.0 9.0 8.0 8.7 8.0 7.7 8.0 8.3 Com Gluten Meal 10-1-0 7.3 6.7 7.3 8.0 8.0 8.0 7.7 7.7 Control -- no fertilizer 6.0 6.3 6.3 5.7 5.7 5.7 6.0 6.0 LSD (005) 0.8 0.7 0.7 1.2 1.4 1.1 1.0 0.8 (0Quality is based on a scale of 9 to 1: 9 = dense, dark green turf, 6 = minimum acceptable quality, and 1 = straw brown turf. - 100- Table 48. The effects of fertilizer source on dried clipping weights*3’ of Kentucky bluegrass for 1991. June May Fertilizer Source 22 28 3 11 18 25 Coron 28-0-0 37.6 39.6 39.3 39.1 25.8 27.6 Nutralene 40-0-0 25.3 29.0 31.3 28.0 18.9 18.1 Sulfur Coated Urea 37-0-0 27.0 36.1 36.2 31.4 25.1 23.5 Urea 46-0-0 40.0 44.2 34.9 40.0 30.3 21.5 Ringer Restore 10-2-6 26.8 39.3 35.0 30.3 30.3 21.5 Ureaform 38-0-0 27.8 33.8 32.4 28.7 19.6 18.9 N-Sure 28-0-0 36.2 36.1 38.6 37.3 24.1 27.8 Com Gluten Meal 10-1-0 23.0 34.3 34.7 27.7 22.3 26.0 Control —no fertilizer 20.7 25.5 26.1 20.1 13.8 14.4 LSD(005) NS 9.8 6.3 7.4 5.2 NS Table 49. The effects of fertilizer source on dried clipping weights*3’ of Kentucky bluegrass for 1991. September August July Fertilizer Source 2 15 12 21 4 10 17 Coron 28-0-0 18.3 28.6 22.3 32.9 41.0 22.1 35.2 Nutralene 40-0-0 15.3 24.7 20.4 24.8 24.3 17.5 35.2 Sulfur Coated Urea 37-0-0 18.6 35.7 31.1 28.8 33.0 19.9 37.3 Urea 46-0-0 17.0 25.4 23.9 35.7 39.6 23.8 38.6 Ringer Restore 10-2-6 22.8 33.7 22.5 23.6 34.9 20.1 38.3 Ureaform 38-0-0 11.9 22.5 22.8 23.6 27.5 17.5 30.7 N-Sure 28-0-0 15.1 23.9 18.9 31.0 42.3 18.2 37.5 Com Gluten Meal 10-1-0 22.1 33.6 21.0 21.8 29.8 18.0 38.8 Control -- fertilizer source 9.5 18.5 13.8 16.9 21.2 11.7 23.3 LSD(0.05) 7.0 NS 5.8 6.2 9.2 4.8 NS *3’Clipping weights are reported as grams dry weight/17.5 ft2. - 101 - O CO (N in rH tH rH rH v 3 CSJ SI rH in T—1 n vo rH rH rH O 6 in ro 03 Q> CJ a O cno o i-i CND 2 0 D d O 2 £ 2 T3 o 00 6 c 4-* ro o <2 c 4-» 3 d bo 03 CO g c Q m- h 03 1 o o CO 3CO 2 g 2 hJ D 2 D u s 1 u u - 102 - Table 51. The effects of fertilizer source on total leaf chlorophyll content of Kentucky bluegrass for 1991. September August October Fertilizer Source 12 21 4 10 17 24 8 Coron 28-0-0 10.5 11.9 14.6 12.6 12.6 15.5 13.0 Nutralene 40-0-0 11.1 11.1 12.5 12.3 13.4 14.5 12.9 Sulfur Coated Urea 37-0-0 12.7 11.9 13.2 12.9 13.4 14.4 13.1 Urea 46-0-0 11.7 11.5 12.5 15.1 13.3 12.8 14.7 Ringer Restore 10-2-6 11.7 10.6 13.2 12.6 12.9 13.9 12.2 Ureaform 38-0-0 11.5 11.5 13.4 12.1 13.0 15.0 13.2 N-Sure 28-0-0 10.9 12.1 15.8 12.6 13.3 15.2 13.5 Com Gluten Meal 10-1-0 11.3 10.8 13.2 12.4 12.8 16.4 12.9 Control -- fertilizer source 10.0 9.7 11.6 10.8 11.1 12.3 11.7 LSDfo^g) 1.0 1.0 1.3 NS 1.3 NS 1.4 Table 52. The effects of fertilizer source on the rooting^ of Kentucky bluegrass on October 17, 1992. Rooting Depth (cm) Fertilizer Source 0-5 5-10 10-15 15-20 Total Coron 28-0-0 (liquid) 91.9 22.9 11.8 10.1 136.7 Nutralene 40-0-0 (granular) 109.7 19.6 4.1 1.2 134.6 Sulfur Coated Urea 37-0-0 (granular) 95.0 18.5 5.7 3.5 122.7 Urea 46-0-0 (granular) 63.6 14.6 8.8 7.0 94.0 Ringer Lawn Restore 10-2-6 (granular) 81.4 30.7 11.4 5.8 129.3 Ureaform 38-0-0 (granular) 90.1 18.5 9.7 6.6 124.9 N-Sure 28-0-0 (liquid) 83.3 15.4 7.5 7.2 113.4 Com Gluten Meal (10-1-0) (granular) 77.1 20.2 13.8 8.3 119.4 Control -- no fertilizer 117.4 34.2 14.5 7.7 173.8 LSD(005) NS 0.012 NS NS (a)Rooting is reported as mg per 150 cm3 of soil. - 103- Table 53. The effects of fertilizer source on soil nitrate content00 on July 17, 1991. Nitrate Depth (cm) Fertilizer Source 0-5 5-10 10-15 15-20 30-35 60-65 90-95 Coron 28-0-0 (liquid) 10.2 10.5 5.1 4.1 2.0 2.0 2.1 Nutralene 40-0-0 (granular) 9.8 6.0 3.6 2.6 1.1 2.3 1.9 Sulfur Coated Urea 37-0-0 (granular) 7.2 4.3 3.6 4.4 1.6 1.5 1.3 Urea 46-0-0 (granular) 10.5 6.0 4.3 3.7 1.5 1.7 2.4 Ringer Lawn Restore 10-2-6 (granular) 7.0 3.0 7.4 5.0 2.0 3.2 2.9 Ureaform 38-0-0 (granular) 8.1 6.4 5.0 3.9 2.0 1.8 4.8 N-Sure 28-0-0 (liquid) 3.7 6.4 6.6 5.1 3.1 1.9 4.4 Com Gluten Meal 10-1-0 (granular) 6.4 7.3 4.9 4.8 2.7 2.9 3.6 Control —no fertilizer 8.0 7.0 1.9 2.6 0.7 1.4 0.6 LSD(0o5) NS NS NS NS NS NS NS (a)Soil nitrate is reported as parts per million (ppm). - 104 - Table 54. The effects of fertilizer source on soil nitrate content(a) on October 15, 1991. Nitrate Depth (cm) Fertilizer Source 0-5 5-10 10-15 15-20 30-35 60-65 90-95 Coron 28-0-0 (liquid) 8.7 10.1 7.4 5.8 3.9 3.9 3.6 Nutralene 40-0-0 (granular) 9.3 7.8 5.6 4.9 3.8 3.9 3.5 Sulfur Coated Urea 37-0-0 (granular) 6.0 9.7 7.6 9.6 6.1 5.3 5.3 Urea 46-0-0 (granular) 12.9 10.5 8.7 7.1 5.2 6.2 5.1 Ringer Lawn Restore 10-2-6 (granular) 9.3 8.7 9.2 7.6 5.8 4.6 5.1 Ureaform 38-0-0 (granular) 8.4 7.9 9.5 8.5 9.9 4.7 8.1 N-Sure 28-0-0 (liquid) 12.5 10.9 6.6 4.9 4.4 5.4 12.2 Com Gluten Meal 10-1-0 (granular) 9.5 5.6 6.4 5.2 10.5 4.9 — Control -- no fertilizer 8.4 7.9 9.4 7.0 5.8 6.8 6.7 LSD(005) NS NS NS NS NS NS NS o 6 U w O CO lo CO CD 4-4 g U W u u O ^ O ro 2 £ in CO W £ rH ON CD 4-4 2 ^ 2 £ ON IN rH ON rH 1 in CN| 00 rH rH rq i z o 5-4 rq C 2 X ¿1 ¿1 00 00 o o CD CD P-I PP PP PP U 5-4 X X 3 CD CXD CXD (D o E E E E CO c c *c c *c o (4 & in rH < cN 3 in rq IN in tv IN n! £ NO ON UJ O qJ CL £ s < o cn D 03 bJD .£ D C Tt rH ON CO o ON in IN ON NO NO NO NO ON NO d 00 in rq o ON CO Ed IN NO in o> =3 Thatch 0-10 cm 10-20 cm C O 20-30 cm CO 30-40 cm c CD co o O 40-50 cm 1 2 Treatment -126 - Drift of Postemergence Herbicide Spray during a Turfgrass Application H. Hatterman-Valenti, M. Owen, and N. Christians Pesticide spray drift is one of the key environmental issues receiving public attention. This is especially true for the lawn care industry because the majority of their business is in residental areas. Therefore, research has been conducted at Iowa State University to quantify the level of off-target particle movement of three common lawn-care spray nozzles under varying wind conditions. A carbon-dioxide pressurized backpack sprayer was used to apply the triethylamine salt of triclopyr at a rate of 1.5 lb a.i./A with the addition of 1% w/v Fluorescein, a fluorescent dye. The three spray nozzles consisted of the XR8004 VS® flat fan nozzles, the RA-6 Raindrop® swirl chamber nozzles, and the Lesco® spray gun. The delivery rates for the three spray nozzles were 0.27, 0.54, and 3.17 gal/min, respectively. The operating pressure and ground speed were adjusted for each sprayer so that the mean volume rates were 20, 40, and 125 gal/A, respectively. The spray application was made along a line perpendicular to the wind direction. Three sampling lines were set perpendicular and downwind from the spray swath edge. Sample location spacing was approximately 1, 3, 5, and 7 ft. Each location had two mylar sheets mounted on poster board and two tomato plants. Wind speed was recorded during the spray application. Immediately following the application, plant samples and mylar sheets were collected and individually stored until fluorescent analysis. One of the two tomato plants at each sampling site was returned to the greenhouse for visual observations of triclopyr injury. Data from the six trials showed that the percentage of application volume lost to spray drift with the mylar or the tomatoes decreased with distance for all nozzle types (Table 66). The greatest percentage was detected with the XR8004 VS® flat fan nozzles at all distances. This was followed by the RA-6 Raindrop® swirl chamber nozzles, with the Lesco® spray gun having the lowest percentage of application volume detected. The measurements taken on the tomatoes returned to the greenhouse indicated that plants within the Lesco® spray gun treatment had the least amount of injury while plants within the 8004 VS® flat fan treatment had the greatest amount of injury (Tables 67, 68 and 69). This was true not only for visual injury symptoms, but also height and fresh weight measurements taken four weeks after the treatment. Distance decreased the triclopyr drift injury on tomato plants. The least growth (i.e. height and fresh weight) occurred with plants at the 1 ft downwind location. On the other hand, plants at the 5 or 7 ft distances were the tallest, with significant differences between them and the control plants. Finally, the least amount of visual injury to tomato plants at all distances occurred with the Lesco® spray gun. - 127- Table 66. Percent of application volume lost to drift. Distance Downwind Nozzle Type 30 cm 90 cm 150 cm 210 cm Fluorescein Dye Collected on Tomato Flat fan 5.63 1.83 0.72 0.69 Swirl chamber 4.37 0.61 0.49 0.31 Spray gun 1.03 0.17 0.15 0.08 Fluorescein Dye Collected on Mylar Flat fan 27.91 4.83 4.02 2.77 Swirl chamber 21.13 2.75 1.41 0.91 Spray gun 10.24 0.49 0.30 0.25 Table 67. Mean increase in tomato height 4 weeks after treatment. Distance Downwind Nozzle Type Control Control 8.54 30 cm 90 cm 150 cm 210 cm Mean3 8.54 Flat fan 1.44 3.64 5.91 8.04 4.99 Swirl chamber 4.11 13.69 14.03 12.89 11.18 Spray gun 9.44 13.56 15.97 13.97 13.23 5.00 10.30 11.97 11.93 Mean* 8.54 3LSD(005) = 5.1 *LSD(005) = 3.1 - 128 - Table 68. Mean increase in tomato weight 4 weeks after treatment. Distance Downwind Nozzle Type Control Control 87.65 30 cm 90 cm 150 cm 210 cm Mean3 87.65 Flat fan 46.22 61.61 79.56 89.13 69.13 Swirl chamber 38.93 72.81 85.07 100.56 74.34 Spray gun 71.05 90.91 99.12 106.69 91.94 52.07 75.11 87.92 98.79 Mean* 87.65 aLSD(005) = 17.5 *LSD(005) = 16.7 Table 69. Mean percent injury to tomato 4 weeks after treatment. Distance Downwind Nozzle Type 30 cm 90 cm 150 cm 210 cm Flat fan 61.11 41.11 26.39 14.78 Swirl chamber 61.38 7.50 2.22 0.28 Spray gun 8.61 2.50 0.01 0.28 - 129- Isolation and Identification of Allelopathic Compounds from Wet Milling Corn By-products D. L. Liu and N. E. Christians Allelopathy is a term used to describe a chemical interaction among plants. It refers to the effects of higher plants of one species (the donor) on the germination, growth, or development of plants of another (receptor) species. The effect which includes both inhibitory and stimulatory influences is exerted through release of a chemical by the donor. Several chemical groups have been implicated as allelopathic agents. They have an important role in crop production and crop protection. To access the chemical specificity for allelopathy, identification of the causal agents is required. Based on earlier studies, there is a possibility that allelopathic compounds exist in com that inhibit the establishment of a variety of plant species by inhibiting root formation during germination. It will be environmentally and economically desirable to exploit the phenomenon of allelopathy in com products as a potential alternative to conventional herbicides. If the purification method of extracting the allelopathic compounds can be established, it could potentially be marketed as a naturally occurring, environmentally safe herbicide and produced in large quantities. This could lead to the development of other related compounds. The purposes of this study are to evaluate the phytotoxicity of various com by-products, to extract and purify the allelopathic compound(s) from the selected products, and to identify the chemical stmcture(s) of the allelopathic compound(s). - 130- Ground Ivy Control with Borax H. Hatterman-Valenti and N. Christians Borax (sodium tetraborate) has been used as an herbicide since the 1950s. Its general herbicidal use is non-selective vegetation control under asphalt or spot treatment of johnsongrass in cotton. For these uses, the application rate ranges from 5 to 15 lb/100 ft2, depending on which form (i.e. anhydrous, pentahydrate, or decahydrate) is used. The element in borax which is responsible for the physiological action in higher plants is boron. Boron is an essential mineral element for all vascular plants. It is absorbed by plant roots and functions in lignification and xylem differentiation. A rapid response to boron deficiency is the inhibition of primary and lateral root growth. Boron deficiency can also cause a number of other symptoms. However, it is the toxicity from high levels of boron that has an herbicidal effect. Sensitivity to boron varies greatly between species, and there is often a narrow concentration range between boron deficiency and toxicity. Typical toxicity symptoms on mature leaves are marginal and/or tip chlorosis and necrosis. Dicots are generally more sensitive to boron than monocots, yet many exceptions have been reported in plant nutrition textbooks. This study was conducted in order to investigate the use of borax to selectively control ground ivy in a cool-season lawn. Twenty MuleTeam Borax® was used for the boron source in the study. A weedy control and applications of Super Trimec® and Sharpshooter® were also included for comparison. Super Trimec® is a combination product consisting of: 2,4-D, 2,4-DP, and dicamba while Sharpshooter® is a fatty acid based, non-selective contact herbicide. The experimental design was a randomized complete-block with three replications. Individual plot dimensions were 5 ft by 5 ft. Treatments included: 5 oz Borax/1000 ft2 (borax mixture with water) 10 oz Borax/1000 ft2 (borax mixture with water) 20 oz Borax/1000 ft2 (borax mixture with water) 1.1 oz/1000 ft2 Super Trimec® 20 oz Borax/1000 ft2 (dry or granular application) Sharpshooter® (ready to use mixture) Weedy control Herbicide applications were made June 18, 1991. Control and injury ratings were taken June 27, July 17, and finally on October 3, 1991. One week after the applications, visual injury symptoms to the ground ivy were evident with the 10 and 20 oz borax solutions, on both the ground ivy and turfgrass. As time progressed, ground ivy control improved so that by October 3 all borax applications and the Super Trimec® provided at least 93% control. Ground ivy within the control plots also decreased over the summer either due to environmental stress or the lateral movement of the borax during heavy rains. Injury to the turfgrass was observed with most of the borax treatments. However, turfgrass injury did diminish with time. - 131 - Table 70. Ground ivy control in a cool-season turfgrass. % Injury to Turf % Ground Ivy Reduction Treatment3 6/27 7/17 10/3 6/27 7/17 10/3 5 oz L. Borax 68 73 98 10 3 5 10 oz L. Borax 93 80 93 30 18 12 20 oz L. Borax 97 92 100 40 13 10 Super Trimec 72 95 100 8 10 2 20 oz D. Borax 52 57 94 18 13 12 Sharpshooter 17 30 63 17 10 8 Weedy Control 0 0 45 0 0 0 LSD(0.05) 18 24 47 NS* 22 20 aL. Borax = Liquid borax solution; D. Borax = Dry borax. *NS = Not significant - 132 - Organic Lawn Care Trial S. M. Berkenbosch, N. E. Christians, and M. L. Agnew This was the second year for this trial located in Ames on the comer of 13th Street and Haber Road. The study was established in 1990 with the objective to observe the effects of two "no pesticide" natural organic fertilizer products at split rates and one complete fertilizer system, using a home-lawn scenario including herbicides and insecticides. This study is being conducted under non-irrigated conditions. The treatments included: Scotts Complete 4-Step Program (4 lb N/1000 ft2) Com gluten meal -- 4 lb N/1000 ft2 applied in spring Com gluten meal -- split treatments of 2 lb N spring and 2 lb N late summer Ringer 10-2-6 —4 lb N/1000 ft2 applied in spring Ringer 10-2-6 -- split treatment of 2 lb N spring and 2 lb N late summer The study contained three control plots and was replicated three times in a randomized complete-block design. All plots were mowed weekly by University Student Housing Department maintenance personnel. The study went into partial dormancy during midsummer. When the data was averaged, it was found that com gluten meal applied at a 4 lb spring application and Scotts 4-Step Complete Program had the best weed control and green-up response. Ringer 10-2-6 applied at the 4 lb N rate and split application of 2 lb spring and fall showed good green-up response but had no weed control. Corn gluten meal applied at a split 2 lb N rate had less green-up but still had above average weed control. Visual quality ratings were based on a visual scale of 9 to 1: 9 = dense, dark green turf, 6 = minimum acceptable quality, and 1 = straw brown turfgrass. Table 71. Natural organic fertilizer trial results, 1991. Fertilizer Source Spring Summer Fall Mean 1 Com gluten meal (4 lb spring) 6.7 8.0 6.3 7.0 2 Scotts Complete 7.0 6.7 5.7 6.4 3 Ringer (4 lb spring) 6.7 7.0 5.3 6.3 4 Ringer (split application) 6.0 6.3 5.7 6.0 5 Com gluten meal (split application) 6.0 6.0 5.7 5.9 6 Control 5.0 5.3 5.0 5.1 - 133- Introducing Iowa State University Personnel Affiliated with the Turfgrass Research Program Dr. Michael Agnew Associate Professor, Extension Turfgrass Specialist Horticulture Department Mr. Dave Anderson Graduate Student and Research Associate Horticulture Department M.S. (Agnew, M) Ms. Susan Berkenbosch Extension Associate, Horticulture Department Mr. Tim Bormann Field Technician, Horticulture Department Mr. Doug Campbell Research Associate, Horticulture Department Dr. Nick Christians Professor, Turfgrass Science Research and Teaching Horticulture Department Ms. Kathy Eldridge Field Technician, Horticulture Department Mr. Pat Emge Field Technician, Horticulture Department Ms. Paula Flynn Extension Associate, Plant Disease Clinic Plant Pathology Department Dr. Mark Gleason Assistant Professor, Extension Plant Pathologist Plant Pathology Department Ms. Harlene Hatterman-Valenti Extension Associate, Weed Science Department Graduate Student Ph.D. (Christians/Owen) Dr. Clinton Hodges Professor, Turfgrass Science Research and Teaching Horticulture Department Dr. Donald Lewis Associate Professor, Extension Entomologist Entomology Department Ms. Dianna Liu Graduate Student and Research Associate Horticulture Department Ph.D. (Christians) Mr. Matt Mixdorf Field Technician, Horticulture Department Mr. Richard Moore Research Associate, Horticulture Department Mr. Glenn Pearston Computer Consultant, Horticulture Department Mr. Gary Peterson Jasper County Extension Director and Graduate Student Horticulture Department M.S. (Agnew, M) - 134 - - Mr. Roger Roe Graduate Student and Research Associate Horticulture Department M.S. (Christians/Agnew, N) Ms. Marcy Simbro Field Technician, Horticulture Department Mr. Doug Struyk Graduate Student and Research Associate Horticulture Department M.S. (Christians) Mr. Steve Starrett Graduate Student and Research Associate Civil Engineering Department M.S. (Christians/Austin) Mr. Ryan Taber Field Technician, Horticulture Department Mr. J. Bryan Unruh Graduate Student and Research Associate Horticulture Department Ph.D. (Christians) We would also like to thank Mark Stoskopf, Superintendent of the Horticulture Research Station, and Adrian Lucas, William Emley, and Lynn Schroeder for their support during the last year. - 135- Companies and Organizations That Made Donations or Supplied Products to the Iowa State University Turfgrass Research Program Special thanks are expressed to the Big Bear Turf Equipment Company and Cushman Turf for providing a Cushman Turfgrass Truckster, a mataway, a lawn aerifier, and a Jacobson Turf King reel mower for use at the research area in 1991; to Tri-State Turf and Irrigation for providing a Greensmaster III Triplex Greensmower and a Groundsmaster 220 rotary mower for use on the research area. American Hoechst Corporation Agricultural Chemicals Department Route 1 Box 7 Brownsdale, Minnesota 55918 DowElanco Midland, Michigan 48674 DuPont Incorporated 1007 Market Street Wilmington, Delaware 19898 BASF Corporation 1000 Cherry Hill Road Parsippany, New Jersey 07054 EniChem Americas, Incorporated Research and Development Center 2000 Princeton Corporation Center Monmouth Junction, New Jersey 08852 Big Bear Turf Equipment Company 10405 ']' Street Omaha, Nebraska 68127 E-Z-Go Textron PO Box 388 Augusta, Georgia 30906 Ciba-Geigy Corporation Agriculture Division Greensboro, North Carolina 27049 Coron Corporation PO Box 198 Souderton, Pennsylvania 18964 Fermenta Plant Protection Company PO Box 348 7528 Auburn Road Painesville, Ohio 44077 Cushman Turf 5232 Cushman Lincoln, Nebraska 68501 Grain Processing Corporation PO Box 349 Muscatine, Iowa 52761 D & K Turf Products 8121 Parkview Drive Urbandale, Iowa 50322 Grace Sierra PO Box 4003 Milpitas, California 95035-2003 - 136 - Lyman-Ritchie Sand & Gravel 4315 Cuming Street Omaha, Nebraska 68131 Grass Roots Turf 6143 Southwest 63rd Des Moines, Iowa 50321 Harmony PO Box 846 Waterloo, Iowa 50704 Milorganite 1101 North Market Street Milwaukee, Wisconsin 53200 International Seeds PO Box 168 820 First Street Halsey, Oregon 97348 Monsanto Company Agricultural Products Division 800 North Lindbergh Boulevard St. Louis, Missouri 63167 Iowa Golf Course Superintendents Association NOR-AM Chemical Company PO Box 7495 3509 Silverside Road Wilmington, Delaware 19803 Iowa Professional Lawn Care Association PBI/Gordon Corporation PO Box 4090 1217 West 12th Street Kansas City, Missouri 64101-9984 Iowa Sports Turf Managers Association Pickseed West Incorporated PO Box 888 Tangent, Oregon 97389 Iowa Turf Producers and Contractors Iowa Turfgrass Institute Professional Turf Specialties Inc 133 Kenyon Road Champaign, Illinois 61820 Lebanon Chemical Corporation Country Club Fertilizer Division PO Box 180 Lebanon, Pennsylvania 17042 O. M. Scott and Sons 14111 Scottslawn Road Marysville, Ohio 43041 LESCO Incorporated PO Box 10915 Rocky River, Ohio 44116-0915 R.G.B. Laboratories Incorporated 1531 Charlotte Street Kansas City, Missouri 64108 Loft-Kellogg Seed PO Box 684 322 East Florida Street Milwaukee, Wisconsin 53201 Rhone-Poulenc Chemical Company PO Box 125 Black Horse Lane Monmouth Junction, New Jersey 08852 - 137- Ringer Corporation 9959 Valley View Road Minneapolis, Minnesota 55344 Tri State Turf & Irrigation Co. 6125 Valley Drive Bettendorf, Iowa 52722 Ross Daniels Inc 1720 Fuller Road West Des Moines, Iowa 50265 UAP Special Products Omaha, Nebraska 68100 Weathermatic Division Telsco Industries PO Box 180205 Dallas, Texas 75218-2005 Soil Technologies Fairfield, Iowa 52556 Spraying Systems Company N Avenue at Schmale Road Wheaton, Illinois 60187 Wilbur-Ellis Company 215 North Summer Street West Burlington, Iowa 52655 Sustane Corporation 1107 Hazeltine Boulevard Chaska, Minnesota 55318 Williams Lawn Seed Company PO Box 112 224 South Hills Drive Maryville, Missouri 64468 Terra Chemical Corporation Box 218 Quimby, Iowa 51049 The Toro Company Irrigation Division Riverside, California 92500 - 138- O and justice for all The Iowa Cooperative Extension Service’s programs and policies are consistent with pertinent federal and state laws and regulations on nondiscrimination regard­ ing race, color, natural origin, religion, sex, age, and handicap. Cooperative Extension Service, Iowa State University of Science and Technol­ ogy and the United States Department of Agriculture cooperating. Robert M. Anderson, Jr., director, Ames, Iowa. Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914.