1996 Iowa Turfgrass i Research Report Department of Horticulture Department of Plant Pathology Department of Entomology Cooperative Extension IOWA STATE UNIVERSITY In Cooperation with the Iowa Turfgrass Institute Iowa State University University Extension Ames. Io w a FG-464 I lulv 1996 Introduction N ickE . Christians and David D. Minner The following research report is the 17th yearly publication o f the results of turfgrass research projects performed at Iowa State University. Copies o f information in earlier reports are available from m ost o f the county extension offices in Iowa. The 1995 season will be remembered as a very wet spring followed by record heat from mid- to late summer. Summer rainfall was spotty, and some local areas experienced drought conditions. The winter o f 95-96 was very cold and some areas experienced severe winter desiccation problems. For the sixth 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 environmental issues that face our turf industry. W ith assistance from the ISU T urf Club, several new sand based golf and athletic field research plots have been constructed on the south end of the T urf Facility at the Horticulture Research Station. Various products and technologies associated with sand based systems will be evaluated such as: SportGrass - a combination o f natural grass and synthetic turf, Heatway - a water circulated soil heating system, SubAir - a subsurface forced air system, several organic and inorganic sand amendments, and a sloped area to study temperature and moisture stress on putting greens. Many of the grant and product contributions for conducting the research are recognized at the end o f this report. Three contributors were especially crucial to the construction and installation of this new research area. Thanks to Dwayne M cAninch (McAninch Corporation) for earth m oving, Tim Johnson (Glen Oaks Country Club) for trenching, M ark Creighton (Reams Sprinkler Supply) and Bruce M organ (Hunter Industries) for irrigation supplies. W e would like to acknowledge Richard Moore, superintendent o f the ISU Horticulture Research Station and Jim Dickson, m anager o f the turf research area; Bryan Unruh, Ph.D. graduate student; Dave Gardener, MS graduate research assistant; Dianna Liu, Postdoctoral researcher; Barbara Bingaman, Postdoctoral researcher; Doug Campbell, research associate, and all others employed at the field research area in the past year for their efforts in building the turf program. Special thanks to Lois Benning for her work in typing and helping to edit this publication. Edited by Nick Christians and David Minner, Iowa State University, Department o f Horticulture, Ames, IA 50011-1100. Dr. Nick Christians Phone: (515) 294-0036 Fax: (515) 294-0730 email: nchris@ iastate.edu Dr. David Minner Phone: (515) 294-5726 Fax: (515) 294-0730 email: dminner@iastate.edu Table of Contents T u rfg ra ss R e se a rc h A rea M a p s ................................................................................................................ 1 E n v iro n m e n ta l D a ta ..................................................................................................................................... 4 Species a n d C u ltiv a r T ria ls Results o f Regional Kentucky Bluegrass Cultivar T rials................................................................. 7 Perennial Ryegrass Study........................................................................................................................ 13 Shade Adaptation Study.......................................................................................................................... 16 Regional Fine Fescue Cultivar Evaluation.......................................................................................... 19 Green Height Bentgrass Cultivar Trial (Native S o il)....................................................................... 21 Fairway Height Bentgrass Study............................................................................................................ 22 H erb ic id e a n d G ro w th R e g u la to r S tudies Preemergence Annual W eed Control S tu d y ...................................................................................... 23 Postemergence Annual W eed Study..................................................................................................... 27 Postemergence Broadleaf W eed Control Study................................................................................ 31 Non-Kerosene, Triclopyr Bee Postemergence Broadleaf W eed Study........................................ 35 Poaannua and Crabgrass Control Study......... Fairway Height Turfgrass Green Height Bentgrass Poa annua Control S tudy......................................................................... 40 Herbicide Demonstration Study............................................................................................................ 42 Dimension/Activated Charcoal Perennial Ryegrass Germination Study..................................... 44 Trinexapac-ethyl (PRIMO) Granular Formulation Study.............................................................. 47 T u rfg ra s s D isease R e search Potential for Genetic M anagement of the Physiology o f L eaf Spot Symptom Expression by Kentucky B luegrass...................................................................................................... 49 Idriella bolleyi as a Factor in the Summer Decline o f Creeping Bentgrass................................ 51 Evaluation o f Fungicides for Control o f Brown Patch in Creeping Bentgrass........................... 53 Evaluation o f Fungicides for Control of Dollar Spot in Penncross B entgrass........................... 56 Evaluation o f Fungicides for Control o f Necrotic Ring Spot in Kentucky Bluegrass............... 58 F e rtiliz e r T ria ls an d Soil Studies Fairway Height Bentgrass Fertilizer Study.......................................................................................... 59 Kentucky Bluegrass Fertilizer Study..................................................................................................... 62 ESN 2003 Mini-size Poly-coated Urea Fertilizer Study.................................................................. 66 Trinexapac-ethyl (PRIMO) Post-Regulation Response Study...................................................... 69 u 39 Toro BioPlex MP and M ultipurpose Soil Biostimulent Effects on a Sand-Based Green.......... 72 E n v iro n m e n ta l R e se a rc h Second Year Field Study o f Com Gluten Meal and Com Gluten Hydrolysate for Crabgrass Control...................................................................................................................................... 74 Using a Split Application to Improve the Effectiveness o f Com Gluten M eal Products....... 77 Field Study to Evaluate Com Gluten Meal and Com Gluten Hydrolysate for Crabgrass Control in T urf......................................................................................................................................... 80 Field Study Comparing the Efficacy of Five Different Com Gluten Meal and Com Gluten Hydrolysate Products for Crabgrass C ontrol........................................................................ 84 Com Gluten Hydrolysate W eed Control Study.................................................................................. 87 Com Gluten Meal Crabgrass Control Study - Y ear Five.................................................................. 89 Com Gluten Meal Rate W eed Control Study - Year One................................................................ 92 Com Gluten M eal/Pendimethalin Interaction Study.......................................................................... 94 Broadleaf and Grass Weed Control with Com Gluten H ydrolysate.............................................. 96 T u r f M a n ag e m en t The Effects of Common De-icing Chemicals on Turfgrass........................................................... 98 Rubber Tire Particles as a Topdressing Amendment for High Traffic G ra ss............................. 101 O rn a m e n ta l S tu d ie s Growth and Development o f Three Container-grown Deciduous Shmbs Started from Bare-root and Potted Liner Stock.............................................................................................. 104 Effect o f Several Organic and Inorganic M ulches on Tree Growth and Soil Properties.......... 105 Effect of Post-frost Pruning on W inter Hardiness of Selected Garden Chrysanthem ums...... 106 Does Premature Branch Removal and Improper Pruning Predispose Trees to Sunscald Injury.......................................................................................................................................... 107 Elms on the Comeback Trail................................................................................................................. 108 In tr o d u c in g The Iowa State University personnel affiliated with the Turfgrass Research Program ........... I l l C om panies a n d O rg a n iz a tio n s that m ade donations or supplied products to the Iowa State University Turfgrass Research Program ................................................................................... 112 iii Wildflower Native Grass Establishment Study o Vantage KBG Ö3 •8* CO Park KBG Parade KBG Ram I KBG Corn Gluten Weed Control Trial Corn Gluten Weed Control Trial Reliant Fine Fescue Glade KBG Corn Gluten Weed Control Trial Baron KBG o XT) S ON C O^^«5 3O 8 C 2 g *¡3 q oa Perennial Ryegrass Cultivar Study High Maintenance Bluegrass 1995 or-~ Buffalograss Management Study LIST Study Limousine KBG Nassau KBG Texoka Common Sharps Limousine KBG •o c jU 'C ’g e2 oo Glade KBG sT3 So ^£ O 00 CX. s oo Ph Turfgrass Research £ Nustar KBG Bronco KBG T3 tí O Fairway Height Bentgrass Green Height Bentgrass T3 O Penneagle Penncross S N R S 261,360 ft“ 6.0 Acres Î Tall Fescue Kentucky Bluegrass Seed Mixtures Fine Fescue Cultivar Study Nustar KBG 00 S tí S £ c CÖ S3 73 -n h >N s O Û CO co On T—H 2O O 3 ON o Premium Sod Blend o o (N P Oh <- 135’ Ornamental Grass Trial 05/20/96 1 135’ Building O 1984 Expansion of the Turfgrass Research Area 108,900 ft. - 2.5 Acres2 e<3 O (640 series heads) Adelphi KBG ? c c g° C o a c o °h 3 cL g ctt o O C J T3 II *1 § s » » cV3« o o s £ ■® V3 V Majestic KBG Vantage KBG ^ et «*■* ^ oo Uh Necrotic Ring Spot Disease Control (690 series heads) Park KBG Ram 1 KBG *2 ‘C H ÌH < D N c Tall Fescue Regional Trial Indigo KBG Park KBG Nassau KBG 13 a> C/3 ^ CÖ C jo 4> 3 O w) 2 Ö O 8 Postemerge Crabgrass t * O -b 1 e a c o U 3 à N 3 c* .2 & Rose Garden SportGrass c* o>'S iQla CGM Pendimethalin Study Heatway and SubAir Greens Amendment Study SubAir Slope Green Study 3 Shade Adaptation Study .02 O vo .50 .02 .89 .44 © 00 ON O - 90% were achieved for 14 o f the herbicide products when compared to the untreated control. 23 Herbicide and Growth Regulator Studies T able 1. The preemergence herbicides, herbicide plus fertilizer formulations, and fertilizer m aterials that were screened1. Product Number of Initial Rate Sequential Rate lb a.i./A Applications lb a.i./A 1 Untreated Control NA NA NA 2 CHIPCO Ronstar G-2GR2 3 Barricade - 65WG3 1 1 4.00 0.65 NA NA 4 Barricade - 65WG3*4 0.75 5 Barricade - 65WG2 1 1 1.00 NA NA 6 Barricade 0.5% + Fertilizer (32-3-12)3 7 Barricade 0.5% + Fertilizer (32-3-12)3 1 1 0.65 0.75 NA NA 8 Pendimethalin 0.86% + fertilizer2 1 1 3.00 1.50 NA NA 2 0.75 0.75 1 0.50 NA 1 1 2 2 2 0.25 0.50 NA NA 0.125 0.25 0.125 0.125 0.25 0.125 1 0.25 NA 18 Dimension- AND447 + fert (39-0-0)4 19 Dimension - AND445 + fert (39-0-0)4 1 2 0.50 0.25 NA 0.25 20 Fertilizer control (39-0-0)4 21 Team 1.15% GR + Fert (27-3-8) PRE 5 NA 1 NA 1.50 22 Team 1.15% GR + Fert (27-3-8) PRE & POST 5 23 Pendimethalin 1.21% GR + fert (28-3-4) PRE5 2 1 1.50 1.50 NA NA 1.50 NA 24 Pendimethalin 1.21% GR + fert (28-3-4) PRE & POST 5 25 Dimension 0.172% + fert (24-4-14) PRE5 2 I 1.50 0.25 9 Pendimethalin-60WDG3&4 10 Pendimethalin-60WDG4 11 Dimension 1 EC2&3 12 Dimension - 1EC + fert(39-0-0)4 13 Dimension - 1EC + fert(39-0-0)4 14 Dimension - 1EC + fert(39-0-0)4 15 Dimension - 1EC + fert(39-0-0)4 16 Dimension- AND444 + fert (39-0-0)4 17 Dimension - AND445 + fert (39-0-0)4 1.50 NA 26 Barricade 0.22% + fert (19-4-6) PRE5 0.50 NA 1 27 Pendimethalin 0.75% + fertilizer 22-0-66 1 1.50 NA 28 Pendimethalin 1.15% + fertilizer 33-3-106 NA 1 1.50 ~ nApplication — 7—7— dates: rr — initial • ... ,----:— :----r r —rr— on April 27, 45-day on June 9 for Trts 10, 12-20, and 8-week on June 21 for Trts 22 & 24. These products were screened for Rhone-Poulenc Ag Company2,Sandoz Agro Inc.3, Rohm and Haas Company4, DowElanco5, and O. M. Scott & Sons6. 24 Herbicide and Growth Regulator Studies ol S3 G cS OX) m ^^r-^^^O OM^ ^^ OC ÛOO OC OÛ OOO ÛO OO ÛC^ OO ^OO t^^h -^ tt © ^ or »t ^^ i^o ts'ûorN^ iv\ûO NO \a\a \a\a \ONO \a\oo oo t^o or^ ts' û c r ' < a .2 3 cs t ^ ^ v o t ^ v o o o M t s>r^t^t^ooc\ooa\C\MC\ooococcot^ocooocooh' 3 Vh oo ONONOooca)ooocvooovooo^ts«rs't s' ^ 3* CD 3 o e M 5 0 h ' û o o o r - t ^ h ' t ^ v û t ^ t s' t s> »— « r^^D^VO^ÛOOC^VOVO^ÛOOOOOOOCOÛOt^OOOOt^t^VOt^M^OOOO ^ c/T o 2 ^r^vot^voooococvov.ovoooaNOoocooococoooor^r^r^r-'r^oooooo e" PX) 00 On Z CO CO c3 H a> ' ^ © ^ ^ © ^ ^ © © 2 o vo ^ q vq Is; o in »n _|_ cs in in in © © © j2 3 n n o a a 1 3 3 CO •r* CN. > (D <]) C-3 Æ £ s a o H c3 T3 T3 a c4 a> -Q « H g -1 Visual quality is based on a scale of 9 to 1: 9 = best, 6 = lowest acceptable quality, and 1 = poorest quality. Application dates: initial on April 27, 45-day on June 9 for Trts 10, 12-20, and 8-week on June 21 for Trts 22 & 24. NS = not significantly different at the 0.05 level. N Herbicide and Growth Regulator Studies u, S oG > VS o o Table 3. Percentage of crabgrass cover in plots o f Kentucky blue grass treated with preemergence herbicides, herbicide plus fertilizer so O'^cNcN'vDTrmrochmr-'Oocomr^Tfr-tnChOmmcNoomcN'Om O N O S ^ O M ^ O O O O h 'O O O N O C O N ^ O N O N ^ C N O N OOONOOOOO n O O ^O O ^ (D cN P4 o s o> ^ >5 U §> s < CM^CM^cnVOCMVOTtCMVOOCVO m G \ CM c n CM TT o c ^ c n a \ o o ^ t n ^ c n ^ c M ^ c M o r - t*n n c M t ^ T r c M r ^ o-p-iv o »-* CM (N tt»ri(N fnooocsO (N M i“H *—i *n CM CM CM oo t: H oo^o *h oo ^ t CM ( N T f CM m 3 ^ »n M ^ cn cn C o r* (L>o (L> O ’’S c3 ci cd c5 ci 3 U O OO Ü o ’£ '£ 3 ffi 03 C3 D O CQ PQffl aJ T3 s a CD CD Ph Oh ^cM n^invot^ooovO ^cM M T r^voM x^o^csnT ftnvo^oc W rH ,-lfH fH r-ti-lrH rH r-lrH (M C M (M C M C M C M C M C M C M Q 00 G _o 3o 3. a. < 26 _ Herbicide and Growth Regulator Studies 1995 Postemergence Annual Weed Study Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Experimental formulations were tested for efficacy as early postemergence materials for crabgrass control in tu rf areas. This study was conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. The experimental site was an area o f Kentucky bluegrass seeded in the fall o f 1994. The soil was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with 3.2% organic matter, a pH o f 5.9, 3.0 ppm P, and 145 ppm K. The experimental design was a randomized block split-plot. Thirteen herbicide products were screened at two different application rates. Individual plots were 5 x 10 ft and three replications were run. Herbicide products were randomly assigned to plots as the main plot treatments. Each 5 x 10 ft plot was split and the two application rates were randomly assigned to the two 5 x 5 ft subplots. AgrEvo USA products AGR 40500, 10 PRECLAIM formulations, PRECLAIM 2.06 EW, and PRECLAIM 2.09 EW were screened. Each product was applied at two different rates. An untreated control was included. Early postemergence application was made on June 12 when the crabgrass plants were in the 2-4 leaf stage o f the first tiller. Pre-treatm ent assessment o f the experimental area indicated that turf quality was uniform. Application was with a carbon dioxide backpack sprayer equipped with #8006 nozzles using a spray pressure o f 25-30 psi. Rainfall was sporadic for the duration o f this study and the temperatures were unusually high. Irrigation was used to provide supplemental moisture to maintain the turf in good growing condition. A post-treatm ent survey o f the area on June 16 showed that all treated Kentucky bluegrass had a uniform yellow discoloration. Symptoms ranged from yellow discoloration to severe necrosis and dead plants. Damage was assessed with a scale from 9 to 1: 9 = healthy grass, 7 = plants discolored (yellowed) with some damage, 5 = severe damage with intermittent necrosis, and 3 = uniform necrosis (Table 1). The grass in m ost plots had recovered adequately to take visual quality data on July 27 and Augnst 10. The ratings were assigned using a 9 to 1 scale: 9 = best quality , 6 = lowest acceptable quality, and poorest quality turf. (Table 2). Crabgrass control was measured by estimating the percentage o f crabgrass cover. Crabgrass germination was detected on May 25 and percent cover data were taken on July 27 and August 10 (Table 3). The Statistical Analysis System version 6.06 (SAS Institute, 1989) and Analysis o f Variance (ANOVA) were used to analyze the data. Least Significant Difference (LSD) means comparisons were m ade to test for main plot (among herbicides) and subplot (between application rates) effects on phytotoxicity, visual quality, and crabgrass control. On June 19 (7 DAT), the bluegrass in plots treated with the herbicide formulations was still tinted yellow. By June 30, phytotoxic symptoms were evident. All o f the herbicides damaged the bluegrass when compared to the grass in the untreated control plots (Table 1). The degree of damage differed among the herbicides. Application rate also affected bluegrass phytotoxicity. In general, the higher rate o f the products caused m ore severe damage than the lower rate. By July 21, the bluegrass in most o f the treated plots had begun to recover. Visual quality data were taken after the bluegrass had sufficiently recovered from the herbicide treatments. T urf quality was sim ilar in treated plots and was not different from the untreated controls (Table 2). All herbicide formulations significantly reduced crabgrass cover when compared with the untreated controls. There were no differences in control between the high and low application rates (Table 3). 27 Herbicide and Growth Regulator Studies Table 1. Kentucky bluegrass phytotoxicity1in plots treated with AGR and PRECLAIM early postemergent _________ annual weed materials on June 12, 1995.______________________________________________ Rate lb a.i./A June 30 17 DAT July 7 25 DAT July 14 32 DAT July 21 39 DAT Mean Phyto 1. Untreated control NA 9 9 8 8 9 2. AGR 40500 2.06 7 7 7 7 7 3. PRECLAIM #1150 2.08 6 6 6 7 6 4. PRECLAIM #1151 2.06 8 6 7 7 7 5. PRECLAIM #1152 2.08 7 6 7 7 7 6. PRECLAIM #1153 2.06 7 6 7 7 7 7. PRECLAIM #1154 2.08 6 6 7 7 7 8. PRECLAIM #1155 2.06 7 6 6 7 7 9. PRECLAIM #1156 2.08 6 6 7 7 7 10. PRECLAIM #1157 2.06 7 7 6 7 7 11. PRECLAIM #1158 2.08 7 6 7 7 7 12. PRECLAIM #1159 2.06 7 7 8 7 7 13. PRECLAIM 2.06 EW 2.02 7 6 8 8 7 14. PRECLAIM 2.09 EW 1.86 6 6 7 7 6 15. Untreated control NA 9 9 8 8 9 16. AGR 40500 3.09 6 5 5 6 6 17. PRECLAIM #1150 3.12 6 5 5 6 6 18. PRECLAIM #1151 3.09 6 5 6 7 6 19. PRECLAIM #1152 3.12 4 4 5 6 5 20. PRECLAIM #1153 3.09 6 5 5 7 6 21. PRECLAIM #1154 3.12 5 4 5 6 5 22. PRECLAIM #1155 3.09 7 5 5 6 6 23. PRECLAIM #1156 3.12 5 5 6 6 5 24. PRECLAIM #1157 3.09 6 5 5 6 5 25. PRECLAIM #1158 3.12 5 6 5 6 6 26. PRECLAIM #1159 3.09 7 6 6 7 6 27. PRECLAIM 2.06 EW 3.03 7 6 7 7 7 28. PRECLAIM 2.09 EW 2.78 7 5 6 6 6 Material 1 1 1 1 1 L SD oos among herbicides 1 1 1 1 1 LSD0os between rates "TTT----:-----------T T ——;-----TT“ 1Visual quality was based on a 9 to 1 scale: 9 = healthy, 7 = discolored (yellowed) with some damage, 5 = intermittent necrosis, 3 = uniform necrosis, 1 = all plants dead. 28 Herbicide and Growth Regulator Studies Table 2. Visual quality1of Kentucky bluegrass 46 and 60 days after treatment with AGR and PRECLAIM early Rate lb a.i./A July 27 46 DAT August 10 60 DAT Mean Quality 1. Untreated control NA 8 7 8 2. AGR 40500 2.06 7 7 7 3. PRECLAIM #1150 2.08 8 7 7 4. PRECLAIM #1151 2.06 8 7 7 5. PRECLAIM #1152 2.08 8 7 7 6. PRECLAIM #1153 2.06 7 7 7 7. PRECLAIM #1154 2.08 7 7 7 8. PRECLAIM #1155 2.06 7 7 7 9. PRECLAIM #1156 2.08 7 7 7 10. PRECLAIM #1157 2.06 7 7 7 11. PRECLAIM #1158 2.08 8 7 7 12. PRECLAIM #1159 2.06 7 7 7 13. PRECLAIM 2.06 EW 2.02 8 7 8 14. PRECLAIM 2.09 EW 1.86 8 7 7 15. Untreated control NA 8 7 8 16. AGR 40500 3.09 7 7 7 17. PRECLAIM #1150 3.12 7 7 7 18. PRECLAIM #1151 3.09 7 7 7 19. PRECLAIM #1152 3.12 6 7 6 20. PRECLAIM #1153 3.09 7 7 7 21. PRECLAIM #1154 3.12 6 7 6 22. PRECLAIM #1155 3.09 7 7 7 23. PRECLAIM #1156 3.12 7 7 7 24. PRECLAIM #1157 3.09 6 6 6 25. PRECLAIM #1158 3.12 7 7 7 26. PRECLAIM #1159 3.09 7 7 7 27. PRECLAIM 2.06 EW 3.03 8 7 7 28. PRECLAIM 2.09 EW 2.78 7 7 7 NS 1 NS NS NS 1 Material LSD(o.o5) among herbicides LSD(o.o5) between rates "T7T-----5" quality. NS = not significantly different at the 0.05 level. 29 Herbicide and Growth Regulator Studies Table 3. The percentage of crabgrass cover in plots of Kentucky bluegrass treated with AGR and PRECLAIM early postemergence annual weed herbicides. Rate lb a.i./A July 27 46 DAT August 10 60 DAT Mean Crabgrass Cover 1. Untreated control NA 4 7 5 2. AGR 40500 2.06 0 1 1 3. PRECLAIM #1150 2.08 0 0 0 4. PRECLAIM #1151 2.06 0 2 1 5. PRECLAIM #1152 2.08 0 2 1 6. PRECLAIM #1153 2.06 0 1 1 7. PRECLAIM #1154 2.08 0 1 1 8. PRECLAIM #1155 2.06 0 1 1 9. PRECLAIM #1156 2.08 0 0 0 10. PRECLAIM #1157 2.06 0 0 0 11. PRECLAIM #1158 2.08 0 0 0 12. PRECLAIM #1159 2.06 0 0 0 13. PRECLAIM 2.06 EW 2.02 0 1 1 14. PRECLAIM 2.09 EW 1.86 0 0 0 15. Untreated control NA 5 12 8 16. AGR 40500 3.09 0 1 1 17. PRECLAIM #1150 3.12 0 0 0 18. PRECLAIM #1151 3.09 0 1 1 19. PRECLAIM #1152 3.12 0 1 1 20. PRECLAIM #1153 3.09 0 0 0 21. PRECLAIM #1154 3.12 0 1 1 22. PRECLAIM #1155 3.09 0 1 1 23. PRECLAIM #1156 3.12 0 0 0 24. PRECLAIM #1157 3.09 0 1 1 25. PRECLAIM #1158 3.12 0 0 0 26. PRECLAIM #1159 3.09 0 1 1 27. PRECLAIM 2.06 EW 3.03 0 0 0 28. PRECLAIM 2.09 EW 2.78 0 1 1 1 NS 1 NS 1 NS Material LSD(o.o5) among herbicides LSD(o.o5) between rates NS = not significantly different at the 0.05 level. 30 Herbicide and Growth Regulator Studies 1995 Postemergence Broadleaf Weed Control Study Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Confront, Vanquish, Garlon and other herbicides in different formulations and tank mixes were screened for efficacy as postemergence broadleaf weed control products in turfgrass (Table 1). This trial was conducted at the Iowa State University Horticulture Research Station north of Ames, Iowa. The experimental plot was comprised o f strips o f common Kentucky bluegrass and partially bare areas that were previously used as planting beds. Both areas were heavily infested with clover and dandelion. The soil in this experimental area was a Nicollet (fine-loamy, mixed, m esic Aquic Hapludoll) with an organic m atter content o f 3.3%, a pH o f 6.00, 23 ppm P, and 151 ppm K. The experimental design was a randomized complete block. Individual experimental plots were 5 x 10 ft and there were 18 treatments with three replications. The study was arranged so each individual plot was approximately 1/2 bluegrass and 1/2 planting bed. Vanquish 4SL (Dicamba DGA) and three different rates o f Vanquish 4SL plus Garlon 3SL (Triclopyr amine) were screened. Two Confront plus fertilizer formulations and Turf builder + 2 with MCPP were applied to both wet and dry foliage. To accomplish this, the plots receiving these products were split to make 2 - 2 1/2 x 10 ft plots. Trimec Classic was included for comparisons (Table 1). The herbicides were applied May 25, 1995. A pre-treatm ent survey of the plot confirmed that dandelion and clover were present in all individual plots and the bluegrass quality was uniform. The liquid formulations were applied using a carbon dioxide backpack sprayer equipped with #8006 nozzles and a spray pressure o f 25-30 psi. The granular herbicides were applied using plastic coated containers as 'shaker dispensers'. Treatments on wet foliage were made immediately following the application o f sufficient water to moisten the foliage. Rainfall was sporadic throughout the duration o f this trial and temperatures were unusually high. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. Kentucky bluegrass phytotoxicity was observed on May 30 and by June 8 symptoms were no longer present (Table 1). Evaluations were made using a scale from 9 to 1: 9 = healthy turf, 7 = intermittent yellowing, 5 = uniform yellowing, 3 = intermittent dead turf, and 1 = uniform dead turf. Estimations o f broadleaf weed infestations were taken on June 28, July 7, and July 14 (Table 2). Assessments were made according to percentage o f broadleaf weed cover per plot. Dandelion and clover were the predominate broadleaf species and were considered together with all other broadleaf species for these data. W eed control data also were taken for dandelion and clover individually. The num ber of dandelions per plot was counted and clover infestations were estimated as percent cover per plot (Table 3). Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis of Variance (ANOVA) procedure. Least Significant Difference (LSD) tests were used to compare means for herbicide effects on bluegrass phytotoxicity, percent weed cover, and weed numbers. On May 30, bluegrass treated with the Vanquish plus Garlon tank mixes and Confront 3SL exhibited phytotoxic symptoms and had significant reductions in quality when compared with the other treated 31 Herbicide and Growth Regulator Studies and untreated plots (Table 1). None o f the other herbicide materials reduced the turf quality when compared with the untreated controls. In turf treated with the herbicide materials, the percentage o f broadleaf weed cover was significantly lower than in untreated turf. Applications on dry versus wet foliage did not significantly affect the level o f control provided by the Confront plus fertilizer formulations and T u rf builder + 2 with MCPP (Table 2). Broadleaf cover reductions > 90% were achieved with some o f the herbicide products. When dandelion and clover populations were considered separately, all herbicide products significantly reduced the number o f dandelion and the percent clover cover when compared with the untreated controls (Table 3). The Confront plus fertilizer formulations and Turfbuilder + 2 with MCPP provided the same level o f control when applied to dry versus wet foliage. Reductions o f > 90% in dandelion and clover cover were recorded for some o f the herbicide materials. T able 1. Kentucky bluegrass phy to toxicity1 in plots treated with postem ergence broadleaf herbicide products on May 25, 1995 Foliage Condition at Phytotoxicity on Application Material Rate (lb a.i./A) May 30 (5 DAT) 1. Untreated Control dry NA 9 2. Vanquish 4 SL2 dry 0.250 8 3. Vanquish 4 SL + Garlon 3 SL2 dry 0.125 + 1.000 5 4. Vanquish 4 SL + Garlon 3 SL2 dry 0.250 + 0.500 7 5. Vanquish 4 SL + Garlon 3 SL2 dry 0.250 + 1.000 6 6. Trimec Classic 3.32 SL2 dry 1.350 8 7. Confront (3SL)2 dry 0.750 8. Confront S-6271 @ (IX)3 dry 0.650 5 9 9. Confront S-6271 @ (IX)3 wet 0.650 9 10. Confront S-6271 @ (1.15X)3 dry 0.750 8 11. Confront S-6271 @ (1.15X)3 wet 0.750 8 12. Confront S-6272 @( IX)3 dry 0.650 9 13. Confront S-6272 @ (IX)3 wet 0.650 9 14. Confront S-6272 @ (1.15X)3 dry 0.750 9 15. Confront S-6272 @ (1.15X)3 wet 0.750 9 16. Turf builder+2 with MCPP 1.21%3 dry 1.500 9 17. Turf buildeH-2 with MCPP 1.21%3 wet 1.500 9 i — 2 L S D ( o.o5) ^ : :— r r ----------------- :— :----------r— Phytotoxicity was assessed using a scale from 9 to 1: 9 = healthy turf, 7 = intermittent yellowing, 5 = uniform yellowing, 3 = intermittent dead turf, 1 = uniform dead turf. These products were screened for Sandoz Agro Inc.2and The Scotts Company3. 32 _ £ £ .2 § 1 0 s J-i § I u on on 00 0 0 NO r-H O oc ON rrN N ON ON OO 00 on rO On ON *o on o04 04 no 2 < 04 04 NO OO 04 no 5 ON 3 ^ co NO 04 04 '—1 ► => 04 TT oo H oo *o NO OO NO ON NO © »3 2 -3 x> £ O o; o Nn 04 + o NO oo N O o + o NO 04 o o o • o NO + co o NO rf 04 O NO oo oO N N O o oNO NO o © 04 co —« t- h oO o N O' NO o o oO N N O © ©O N NO © ©O N O^ © o4I — ©O © © N ©O o* «©O N © 04 2 g CO CO CO CO CO G o Th o3 o G O T3 a O G O *G 03 o + + + p CO P CO p CO o GO TT TJ* u *G *G G3 3 *3 ’3 *3 V- & oG r cGr Gc r G § C3 03 ccj o > > > > • 04 co CO XT P GO 04 co co’ o p *cO G O S co o g 8 3 X 1 X NO X NO X ✓— \ X @ 04 O' O" o04 04 C N 04 NO NO NO NO 04 NO CO GO CO CO GO G G G O O O O O G G (L> (dry) CÔ *n 3 CD P CO (wet) o x X X NO Nn ^ ® ® 04 04 r04 04 ND N O GO GO G G 04 04 NO U NO 33 O U O O U U O U eu a, eu fu U U S S > 04 + 04 £ + NW P CO P Dandelion and clover were considered in estimating these percentages. These products are being screened for Sandoz Agro Inc.2 and The Scotts Company3. < *n T—î r— H ® r_H CN NO i GO G <2 «4-1 G O U ® r»H rCN NO l G0 ,, G «<§ 4-1 G O O ® _| rCN NO I G0 G Oh ,5«4— t G O O 00 On O ▼ -H »n in ON ON NO ON o o ^r o in CN © + J GO GO cn cn g 05 o O 'taj C3 O o + + + o in CN o On o cn g G O GO Tf U ”0 xs c/5 o3 *3 (L> cr .¿2 a GCC P > X00 ’3 cr G G > '3 cr G ci > GO cn C3 cs ^ O >J 1(»g C/D c3 CN O cn cn H *-H cn tt *n CN GO Tt p GO ^T *G C/i NO* 34 R R in ’“J r-H ® r-H rCN NO G0 G O <+h G O U 00 OO CN On On cn r-H r- o in NO o o »n NO o’ o in ro o in 1 1 /~S (D £ ON R «n ON CN in CN NO CN o o in ,-h O o »n o £ CN CN R Ph o . >< N—/ 4— H »n ’“"J r-H ® CN rCN NO i G0 4-» G «<2 4-1 G O U ® CN rCN NO l G0 4-> G J«4-1 G O U ® CN rCN NO 1 G0 G O «4-1 G O U ® CN rCN NO i G0 4-* G O «¿3 G O U CN 1— H en r-H TT r-H r-H s >< 00 r-H CU Oh Ph U O 2 2 £ £ % CN CN t 2 *3 rQ t g " flD G uh G~ ~ uh è , ^ ° ìÌ ^ i-i-8 R D X> * 1 .8 "CO j2 G 8 CJD 3 4P I 'S ’S 1O CO h cO cO d ~ d h > , Ö S ’^ ’S 1s ^"*8> U ü plants brown, all dead, even border Herbicide and Growth Regulator Studies o 3CO C/5 3 § . <„ 2 •» -S oo ^| 5 ’S ’S U S •Ö f t 4D _&> -o •S J-® a) CD C - £_) I G d C/3 C CN 3 o T3 § a G d > CD Uh Ö0 •£2 ’SCD fut S”S „ CD I 'S ’S * |- S 2GG = G c »sG ^ > g 3 & g2 cd g-S-S I § s £ 9-° g ft§ 9 -ss ÏÎ > Jp* 3CD 4P 4P 3 TC3D aCD" slight browning, even border o Pd CD > G~ CD ! ’s ’s 2 B- sè ’S, ü Vi (D W w„ 8 rQ cd o <*> •M s CD 2 .£ Oö 3*3 G S HUh 4P co a > o 3 O h ra S T O o!—I CO Uh CD TU3h G cO 4P CD 3 O G öt JP 3 ■s G 2 S l CD G o .* ü r>> 3 G 3 3 G G July 14 O *0 S G &.S 5 CN 2 o 4PP h G cO iS Uh 43 Monsanto #65005 O Herbicide and Growth Regulator Studies 1995 Dimension/Activated Charcoal Perennial Ryegrass Germination Study Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Activated charcoal was screened for effectiveness in deactivating Dimension 1EC. This study was conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. The experimental site was in an area o f common Kentucky bluegrass and the soil was a N icollet (fineloamy, mixed, m esic Aquic Hapludoll) with an organic m atter content o f 2.2%, a pH o f 6.0, 12 ppm P, and 86 ppm K. The experiment was designed as a randomized complete block. The individual plots were 5 x 5 ft and three replications were conducted. Dimension was applied at three rates (0.5, 1.0, and 2.0 lbs a.i./A). Each of these rates were screened in combination with activated charcoal applied 1 and 15 days after the Dimension. The charcoal was applied at 100 lbs/A. An untreated control, a plot receiving Dimension 1EC at 0.5 lb a.i./A and no charcoal, and plots treated with charcoal at 1 and 15 days were included for comparisons (Table 1). Dimension 1EC was applied on May 4 using a carbon dioxide backpack sprayer equipped with #8006 nozzles using a spray pressure o f 25-30 psi. A pre-application survey was conducted and the turf quality was uniform throughout the experimental area. Activated charcoal was applied using plastic coated containers that served as 'shaker dispensers'. The one-day treatments were applied on M ay 5 and the 15-day charcoal was applied on May 19. Perennial ryegrass overseeding was performed June 2 (14 days after the last charcoal treatments were applied and 29 days after the Dimension 1EC was applied). Prior to overseeding, the bluegrass was mowed to a height o f 1". The clippings were removed and the plot was verticut in two directions. The residue was removed and the ryegrass was seeded with a slit seeder in two directions. A drop spreader was used to seed in two diagonal directions. An endophyte enhanced ryegrass seed (#4200 from Seed Research o f Oregon, Inc.) was planted at approximately 10 lb s/1000 fir. After seeding, the plot was rolled lightly and P was applied at 1 lb/1000 ft2. Rainfall occurred on June 2 and June 3. Rainfall was sporadic for the duration o f this study and the temperatures were unusually high. Supplemental irrigation was used to provide enough m oisture for good turf growth and ryegrass germ ination. The plots were checked for Kentucky bluegrass phytotoxicity on May 5, M ay 19, and M ay 30. Visual turf quality ratings were taken May 19, May 30, June 16, June 28, July 6, July 21, and July 28. Assessments o f turf quality were based on color, texture, and thickness using a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 1). Crabgrass cover data were taken to ensure that Dimension was providing crabgrass control and to check for possible decreases in the level o f control when activated charcoal was applied. Crabgrass control was assessed by estimating the percentage of crabgrass cover per plot. Crabgrass germ ination was detected on May 25. Percentage o f crabgrass cover data were taken on June 28, July 6, and July 21 (Table 2). Establishment o f perennial ryegrass was measured by counting the num ber o f plants per sample area within each plot. Destructive sampling was employed and 2" diameter plugs were random ly taken from each plot using a soil core sampler. Ryegrass counts were m ade on July 28 and August 11 and were reported as the number o f ryegrass plants/ft2 (Table 3). Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis of Variance (ANOVA) procedure. Least Significant Difference (LSD) tests were used to 44 Herbicide and Growth Regulator Studies compare means for Dimension effects on visual quality, on percentage crabgrass cover, and on ryegrass establishment. There were no symptoms o f phytotoxicity on the Kentucky bluegrass treated with Dimension at any rate. On all data collection dates, bluegrass quality was uniform among the plots (Table 1). Crabgrass cover was maintained at < 5% by Dimension at all application rates (Table 2). The addition o f charcoal to Dimension treated plots did not significantly alter the level o f crabgrass control. Charcoal with no Dimension did not affect crabgrass cover when compared to the untreated control plots. The m ean num ber o f ryegrass plants/ft2 in plots receiving Dimension at 0.5 lb a.i./A and charcoal (Treatments 2 and 5) was significantly higher than in plots receiving Dimension at 1.0 and 2.0 lb a.i./A with charcoal added at either 1 or 15 days (Treatments 3, 4, 6, and 7). The num ber of plants/ft2 was similar in plots treated with Dimension at 0.5 lb a.i./A and charcoal, Dimension at 0.5 lb a.i./A without charcoal (Treatm ent 8), no charcoal and no Dimension (Treatment 1), and charcoal only at either 1 or 15 days (Table 3). Table 1. Visual quality of Kentucky bluegrass plots treated with Dimension and Dimension plus activated charcoal ________ and then overseeded with Perennial ryegrass1.________________________________________________ lb a.i. /Acre May 4 May 5 May 19 May 30 June 16 June 28 July 6 July 21 1 Untreated control NA 9 9 9 9 9 9 9 8 2 Dimension-1 day charcoal 0.5 9 9 9 9 9 9 9 8 3 Dimension-1 day charcoal 1.0 9 9 9 9 9 9 9 8 4 Dimension-1 day charcoal 2.0 9 9 9 9 9 9 9 8 5 Dimension-15 day charcoal 0.5 9 9 9 9 9 9 9 8 6 Dimension-15 day charcoal 1.0 9 9 9 9 9 9 9 8 7 Dimension-15 day charcoal 2.0 9 9 9 9 9 9 9 8 8 Dimension-no charcoal 0.5 9 9 9 9 9 9 9 8 9 Charcoal control-1 day NA 9 9 9 9 9 9 9 8 10 Charcoal control-15 day NA 9 9 9 9 9 9 9 8 — NS NS NS NS NS NS NS NS Treatment L S D ( o.o5) T T 1 Dimension was applied on May 4, 1 day charcoal on May 5, and 15 day charcoal on May 19. Overseeding with Perennial ryegrass was performed on June 2. Quality based on a scale of 9 to 1: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality. NS = not significantly different at the 0.05 level. 45 Herbicide and Growth Regulator Studies Table 2. Percentage of crabgrass cover in Kentucky bluegrass plots treated with Dimension and Dimension plus ________ activated charcoal and then overseeded with Perennial ryegrass1._______________________________ Mean% crabgrass cover lb a.i. /Acre June 28 July 6 July 21 1 Untreated control NA 27 35 43 35 2 Dimension-1 day charcoal 0.5 0 1 1 1 3 Dimension-1 day charcoal 1.0 0 1 1 1 4 Dimension-1 day charcoal 2.0 0 1 2 1 5 Dimension-15 day charcoal 0.5 2 2 4 3 6 Dimension-15 day charcoal 1.0 0 1 4 2 7 Dimension-15 day charcoal 2.0 0 1 1 1 8 Dimension-no charcoal 0.5 1 1 5 2 9 Charcoal control-1 day NA 32 45 55 44 10 Charcoal control-15 day NA 37 48 58 48 14 18 20 17 Treatment LSD(o.os) 1 Dimension was applied on May 4, 1 day charcoal on May 5, and 15 day charcoal on May 19. Overseeding with Perennial ryegrass was performed on June 2. Table 3. The number1of perennial ryegrass plants/ft2 in Kentucky bluegrass plots treated with Dimension and ________ Dimension plus activated charcoal and then overseeded with Perennial ryegrass.2________________ lb a.i. /Acre July 28 August 11 Mean Number of ryegrass plants/ft2 1 Untreated control NA 80 84 81 2 Dimension-1 day charcoal 0.5 126 115 122 3 Dimension-1 day charcoal 1.0 23 31 25 4 Dimension-1 day charcoal 2.0 0 0 0 5 Dimension-15 day charcoal 0.5 107 54 89 6 Dimension-15 day charcoal 1.0 19 38 25 7 Dimension-15 day charcoal 2.0 4 8 5 8 Dimension-no charcoal 0.5 80 46 69 9 Charcoal control-1 day NA 122 46 97 10 Charcoal control-15 day NA 199 176 191 115 NS 77 Treatment L S D ( o.o5) 1 Four plugs per plot were sampled for Perennial ryegrass plants on July 28 and 2 plugs per plot on August 11. 2 Dimension was applied on May 4, 1 day charcoal on May 5, and 15 day charcoal on May 19. Overseeding with Perennial ryegrass was performed on June 2. NS = not significantly different at the 0.05 level. 46 Herbicide and Growth Regulator Studies 1995 Trinexapac-ethyl (PRIMO) Granular Formulation Study Barbara Bingaman, Nick Christians, and David S. Gardner Granular formulations o f the growth regulator, Trinexapac ethyl, were evaluated to confirm application rates and to test the efficacy o f these products on good to high quality lawn turf. This study was conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. The experimental plot was a 10-year old stand o f 'Park' Kentucky bluegrass on a Nicollet (fineloamy, mixed, m esic Aquic Hapludoll) soil with an organic m atter content o f 3.6%, a pH o f 7.00, 4 ppm P, and 106 ppm K. The study was arranged in a randomized complete block design. Three replications were conducted. Individual experimental plots were 5 x 5 ft with 3 ft barrier rows between replications. Four Primo granular form ulations (FL950477, FL950478, FL950473, and FL950474) and Primo IE were screened. A fertilized control and an untreated control were included for comparisons. Primo IE was used at the label rate for Kentucky bluegrass o f 0.26 lb a.i./A (0.75 fl oz/1000 ft2) and the Primo granule materials were applied at 0.34 lb a.i./A (Table 1). All treatments were applied May 19. Prior to application, the experimental site was examined and the tu rf was found to be quite uniform in color and overall quality. A carbon dioxide backpack sprayer equipped with 8006 nozzles with a spray pressure o f 20-25 psi was used to apply the Primo IE. The granular materials were applied using plastic coated containers as ‘shaker dispensers’. The first rainfall after application occurred on May 22, and rainfall was sporadic for the duration o f this study. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. Visual quality and fresh clipping weight data were taken weekly for seven weeks from May 25 - July 13. Visual quality assessments were based on color, density, and phytotoxicity and recorded using a scale o f 9 to 1: 9 - best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 1). Mowing height for collecting clippings was 2" (Table 2). Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) by using the Analysis o f Variance (ANOVA) to test the significance o f the treatment effects on the visual quality and clipping weights. Least significant difference (LSD) were used to compare means among the treatm ents. Kentucky bluegrass phytotoxicity was detected on June 5 and June 12 in plots treated with Primo IE. By June 19, however, the quality was uniform among all treated and untreated plots (Table 1). Significant differences in fresh clipping weights were recorded among the treated plots for May 25, June 5, and June 12. On May 25, clippings were decreased in plots treated with Primo IE and 2 Primo granule formulations, FL950477 and FL950478, when compared with the untreated and the fertilized control plots. On June 5 and June 12, clipping weights were significantly reduced by Primo IE and all Primo granule formulations as compared with the untreated control (Table 2). Total clipping weights for bluegrass treated with Primo IE, FL950477, and FL950478 were significantly reduced when compared with the untreated control. No post inhibition stimulation was observed in bluegrass treated with these materials. Primo 1E was the most effective material in reducing clipping weights, followed by FL950477 and FL950478. Granular formulations FL950473 and FL950474 were not effective in reducing total clipping weights when compared with the untreated control (Table 2). 47 VO VO VO V© VO vo NO Z m cv; 'u GO vo o 154 ^ Q P> to vo ► — 1144 2 < 1184 Herbicide and Growth Regulator Studies vo on GO z Q S 00 VO ON o s £ § w on Ot o H ^ < Q >—> cn GO § z < Q ? É? Q 2 00 OC OO OO 00 oc & GO ON .. > t—< JL> CU c/5 ac I O P P C 3 S3 03 2 !o u T3 3 U, a> 3 es H r- 00 r m- "Pr ^ 3- o TT o O T of • o *o »o VO ON ON ON ON Un P h Uh Uh Ü 3 3c 3p 3p 3 p Vh W 20 2p »-I Û G oc G oc o c o O o o o s a a S P C pu cs *c Cu eu Ph Cu e VO NO 5 *o o VO p CN 3 & U-l ° O O < L>’S eu z 1* *p o f/i P S o S *P ^ >> % 3 £ 2 § S aj c/i îti w>g .S Sb 3 ’a 3| O P •B d> 3 2 , VO *—t o cn cn rtt o VO ON H-l o 5a o u a> 3 a> « D .Sz 3 H < Q VO s O ^ Q GO >-1 Q T3 P ON H P i— ( < o Q w O ►*» cn s—✓ P ^P *c cu /^s X (N H £ r-H < * J P ~5 CS U ts CA o 3 vo H CO (L> < C/5 Q g Lh § roc v—/ ^P 3 3 p IT Uh P W o s - h CS rf-t II A co -a z 48 oo rrf O VO ON Ioo toIV o o s s h NS z 25 GO 36 VO LSD «».os) 39 ‘Clipping weights are grams fresh tissue. NS = Not significantly different at the 0.05 level. VO 54 vo 153 VO 281 VO 334 VO 7 Primo granule FL950474 NO on 59 Q Q oo TT 161 s 3 275 < 380 a> *2 CS TJ o TJ o m «Al «Al «Al V r- O es CN o O o CD *6 .4-4 O < o O o P O O «^ © O O o «4-f © © •8 «Al CN CN o «4C -4 D «4-1 «Al O CN o O <4 4) 6 JW <-D TJ TJ oc oc O o o O CN o o oc oc o o o © «£P © P oc : 0Û oc oc «Al oc oc 1 © © © CN © «Al ! © © ©* © o © 42 O O 42 © 42 O O 1 42 !° 1O 00 cs 00 N Q «Al CN Q N O «4C — 4 D «Al CN O •8 «Al CN CN <4-( Nm © © •S «Al © «4-4 © © «A> CN <*4 P © © ’ «£? «Al r© oc oc «Al oc «Al CN © CN © © © 42 O O 42 O © 42 © © JD O O CN CN CN CN CN N O N O N O © ND © «Al r© ©3 «Al N O © CN N O © en i -9 «4-4 : KJ © j © ©* | en «Al © s oo ce O TT Table 1. 1995 Evaluation o f fongicides for control o f brown patch in creeping bentgrass. ce CS «O -O «Al o CN o O JO o o ce fc g H H 00 o 3CD ce § « U w S3 S3 £ £ £ & £ o o o o o Q Q Q P Q H 54 _ o X cb o CN <+H T3 in o ’ o X m X ’“O o X cb »n CN CN* bi) O o’ b0 O o’ -a o X in CN CN Cm O -o Xcb o in o CN co* bD bJD in © O* o ’ bfi in o’ bJO bfi *n o CN o’ o’ bO «SP X O O X o o' JO o X o o’ X O CN CN CN CN CN N O N O N O N O *n CN o* <4H 1) W 4.0a o ’ 00 o o o’ 0.0 b CN CN Ph Q in CN s CN a o Q in ro cp £ o IT) Ph Q m CN 0O O £ «— & Ph jj cq + Ph Q Ph Q o o m m N O O CN* N O O H Ph Pu, £ o in £ X CO CO CO V3 *n Ph Q o lb u + oo r- CN *n ! ]? 1 S s s a cb lb N O O CO* U u in < pp Ph in < in < u *s O o cb Q cb Cb o W £ o Q CN o 00 Ph o 7 cb £ o o* o o’ 5.0 oz. VO o o' Spottrete CN .bO Cm in s K o Q c X o d °0 S X q d OQ m m CQ CQ CQ Cleary's oc CN VO in CN X CN CN OO CN o CO CO CN CO CO CO 34 H 55 Lh c3 5> ov CN Lh G & Ph Rating scale: 0 = no disease, 1 = 1-5% disease, 2 = 5-10%, 3 = 10-25%, 4 = 25-50%, 5 = >50% of plot symptomatic. Means in a column followed by the same letter are not significantly different (DMRT, p = 0.05). N = 4. First application date was 6/28. CN in CN o’ <4H o o> X c3 o X in m CN 1.5bcdef vo 2.0abcdef Turfgrass Disease Research Turfgrass Disease Research 1995 Evaluation of Fungicides for Control of Dollar Spot in Penncross Bentgrass MarkL. Gleason Trials were conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. Fungicides were applied to Penncross creeping bentgrass maintained at 5/32-inch cutting height, using a modified bicycle sprayer at 30 psi and a dilution rate o f 5 gal/1000 ft2. The experimental design was a randomized complete block with four replications. All plots m easured 4 x 5 ft. After inoculation o f the entire plot with pathogen-infested rye grain, spray applications began on June 7. Subsequent applications were made at specified intervals on June 14, 21, 28, and July 5, 12, and 19. Dollar spot symptoms appeared in the plot during the week of June 19. Disease development was moderately severe during late June through late July. On July 14 and 26, all treatments gave significant (P=0.05) disease suppression in comparison to the untreated check. N o phytotoxicity symptoms were observed during the trial. 56 Turfgrass Disease Research 1995 Evaluation of Fungicides for Control of Necrotic Ring Spot in Kentucky Bluegrass MarkL. Gleason Trials were conducted on 'Ram I' Kentucky bluegrass at the Iowa State University Horticulture Research Station north of Ames, Iowa. Fungicides were applied to turf m aintained at 3-inch cutting height, using a modified bicycle sprayer at 30 psi and a dilution rate o f 5 gal/1000 ft2. The experimental design was a randomized complete block with three replications. All plots measured 4 ft x 5 ft. The trial was located on a site where necrotic ring spot symptoms and pathogen were confirmed in 1994. Fungicide applications began on June 9 and were repeated at recommended intervals on June 28, July 7 and 21. Symptoms were apparent by June 1. W eather during June and July was close to the long-term average for central Iowa with regard to temperature and rainfall. Disease development on the untreated check plots varied considerably among rating dates and among subplots on the same rating date. In general, treatm ents did not provide significantly better control than the untreated check. No phy to toxicity symptom s were observed. Table 1. 1995 Necrotic Ring Spot Trials % area symptomatic1 Trt # Company Material Rate/ 1000 ft Intervals June 21 June 28 July 26 Aug. 7 - - 11.25ab 4.5ab 18.25ab 13.75ab 20.0a 7.5a 27.5a 22.5a 1 Check - 2 Scotts S-6115 1,200 g 28 3 Scotts S-6128 1,150 g 28 1.25 b 1.25ab 1.75 b 1.75 b 4 ISK Biotech Fluazinam 500F 1.0 oz 21 4.25ab 1.5ab 4.25b 3.25b 5 ISK Biotech Fluazinam 500F 2.0 oz 28 4.5ab 1.75ab 4.25b 4.25b 6 ISK Biotech Fluazinam 500F 1.0 oz. 28 6.5ab 5„0ab 12.5ab 4.0b +Banner 1.1 EC 2.0 fl. oz. 28 1.25b 0.5b 0.5b 0.25b 7 Rohm & Haas Eagle 40 W 1.2 oz. 1 Means in a column followed by the same letter are not significantly different (DMRT, P=0.05). N=4. 58 Fertilizer Trials and Soil Studies 1995 Fairway Height Bentgrass Fertilizer Study Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Natural fertilizers from Toro and other natural products were screened for their effects on bentgrass quality and growth. This trial was conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. The experimental plot was in an area of 'Dominant' creeping bentgrass maintained at a m owing height of 1/2” . The soil in this experimental area was a Nicollet (fineloamy, mixed, mesic Aquic Hapludoll) with an organic m atter content o f 2.6%, a pH o f 7.85, 6 ppm P, and 50 ppm K. Individual experimental plots were 5 x 5 ft and there were nine treatments with three replications. Barrier rows 2 ft wide were placed between replications. The experimental design was a randomized complete block. Five natural product fertilizers (29-0-0, 22-3-3 + Fe, 12-16-8, 1.95-1.1-30, and 18-0-18) from Toro were tested as were granular com gluten meal, Sustane (turkey manure), and Renaissance (a natural soy product from Fairway Green Inc.). All products were applied at the yearly rate o f 2 lb N/1000 ft2 in split applications o f 1 lb N/1000 ft2. An unfertilized control was included for comparisons. The plot was m owed to a uniform height o f 1/2" before fertilizer application. A survey of the experimental area was made prior to treatment and the bentgrass was uniform in color and overall quality. The fertilizers were applied using plastic coated containers as 'shaker dispensers'. Initial applications were made on July 11. The materials were watered-in with the irrigation system and the plot was mowed to 1/2" on July 13. The first post-application rainfall occurred on July 16. Rainfall was sporadic throughout the duration o f this trial and temperatures were unusually high (Table 2). Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. Sequential applications were m ade on September 8. The materials were watered-in using the irrigation system and the plot was mowed to 1/2" on September 10. The first substantial post­ application rainfall occurred on September 19, 20, and 21. Phytotoxicity data were taken on July 14 and September 11. Bentgrass phytotoxicity was estimated losing a 9 to 1 scale: 9 = no damage, 7 = 30% damaged, 5 = 50% damaged, and 3 = 70% damaged turf per plot (Table 1). Visual quality data were taken on July 25, August 4, 11, 23, September 1, 20, 27, October 4 and 11. Visual quality was assessed losing a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 2). Fresh clipping weights were measured on August 11, 23, September 1, 27, October 4, and 11. The mowing height for collecting clippings was 3/8" (Table 3). There were schedule modifications in data collection due to adverse weather conditions. Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis o f Variance (ANOVA) procedure. Least Significant Difference (LSD) means comparisons were used to assess fertilizer effects on bluegrass quality and clipping weights. Significant phytotoxicity was found in bentgrass treated with the Toro product with an analysis of 1.95-1.1-30 (Treatm ent 8). W ithin three days after the initial and sequential applications, as much as 50% o f the bentgrass was damaged in plots treated with this material. This phytotoxicity probably was the result of the high level o f K applied. Because o f the low N content, it was necessary to apply a large amount of this product to equal the 1 lb N /l 000 ft2 rate. The bentgrass recovered quickly and 59 Fertilizer Trials and Soil Studies within 10 days the symptoms were no longer present. None o f the other fertilizers caused any substantial damage to the bentgrass (Table 1). Problems were encountered with all fertilizer products. The particle sizes were too large and they remained on the bentgrass surface even after being thoroughly watered-in using the irrigation system. Much o f the material was rem oved by the mower and the removal o f product could explain the lack of definitive results. There were no significant differences in visual turf quality among the fertilizer materials and the untreated controls. The mean visual quality also was similar for all o f the treatments and did not differ from the untreated control (Table 2). There were small differences in clipping weights but significant differences among the treatments were only recorded for October 4 and October 11 (Table 3). On October 4, the clipping weights for bentgrass treated with Renaissance were higher than the untreated control and all other fertilizers, except one o f the Toro products (Treatment 8). On October 11, bentgrass fertilized with Toro fertilizer (Treatment 8) and Renaissance were significantly higher than the untreated control and all other fertilizers, except Sustane and another Toro product (Treatment 4). M ean and total clipping weights were similar for the untreated controls and all the fertilizer products. Table 1. Phytotoxicity1in Kentucky bluegrass fertilized with natural product and other fertilizers. Product July 14 September 11 Mean phytotoxicity 1. Untreated control 2. Granular com gluten meal (10% N) 3. Renaissance (6-0-6) 9 9 9 9 9 9 9 9 9 4. Toro fertilizer (29-0-0) 8 8 5. Toro fertilizer (22-3-3 + Fe) 9 9 9 9 6. Toro fertilizer (18-0-18) 7. Toro starter (12-16-8) 9 9 8 8 9 9 8. Toro fertilizer (1.95-1.1-30) 9. Sustane (5-2-4) 5 9 6 7 5 8 1 2 1 L S D ( o.o5) 1 Phytotoxicity was assessed using a 9 to 1 scale: 9 = healthy, 7 = 30% damaged, 5 = 50% damaged, and 3= 70% damaged turf. 60 Fertilizer Trials and Soil Studies S£ o c o o o c o c o c o o o c o c o c GO z 0 1Ha>-» s-* -4a> a 5V o O o o o o o o o o o o o o o o o o o o z GO G C3 o O 0 \ O \ O \ 0 n C \ G \ 0 n 0\0\ £ 5 a o C/5 G r- cn Oh o o c o c o n o c o o o o o o o c o o 3 o GO z CN Oh a> o o o o o o o o o o o o o o o o o o Oh > P r ^ o o o o o o o o o o o o o o o o G c3 o no G G cr G fS O) 3 es H r-' cn t t vo t (N t on on n cn trf 00 00 W -H 8 oo ip p ON ^ >y J*r wo o o 3 a 3 > O o 1S °* o 04 hO c3 cS £ o CO g "SI GO 3o 3 CNTi-OO^t^OOO(NVD^ (S (S fn n (S (S fn tfn 2 o *§ o ai 3 H o c— CN Dh a GO z vooNcNooocr^r-^r-oc ( N c N v o m c n m c n t n c o —' ~o cor / N w c snj oc oNrm c o c N C oNcconocNn cmo^XH; a o 1 00 GO *0 g 3 o •§> H VO I N oI O o c3 § , 3 g3 e § g o & H a> tin + cn I CO N CO 4 CO H-> 3 C3 oI oo ^ ' *5 £ od vn ON pQJ »-H 54 ^ 0 ro ^ t: < t:L> D ,< Cfl ,t> o Q to o o o G GO H H H GO »-a I '-^cNcoTrvnvDr^oooN g 3 § 3 3 *G Vh Uh fl cr H-* — O 2 a M II s (L> o p no o ^ ^ 0 0 1 o o n3 o 3 3 o dv N cn 00 1—1 1 0 00 T— H Vh O N 3 3 3 W-H O Jh O H H a> N ^H — 3, 0 ) »0 00 G g .2 ? ^ Vh O Vh 0 H G 3 00 Q G 00 C/0 J g OO H-H •s Oh§W S ll u 61 a ^ 3 z Fertilizer Trials and Soil Studies 1995 Kentucky Bluegrass Fertilizer Study Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Natural organic fertilizers were screened with naturally derived and other fertilizers for their effects on turf quality and growth. This trial was conducted at the Iowa State University Horticulture Research Station north of Ames, Iowa. The experimental plot was an area o f ‘Park’ Kentucky bluegrass with a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) soil with an organic m atter content o f 3.3%, a pH o f 7.0, 7 ppm P, and 86 ppm K. The experimental design was a randomized complete block. Individual experimental plots were 5 x 5 ft with 11 treatments and three replications. Three-foot barrier rows were placed between replications. Com gluten meal, Sustane (turkey m anure), Ringer's organic fertilizer, M ilorganite (activated sewage sludge), and two Toro materials were applied at a yearly rate o f 4.0 lb N/1000 ft2 in split applications. A natural soy product, Renaissance, was applied at different rates in single and in split applications (Table 1). An unfertilized control was included for comparisons. Initial treatments were made on May 15. The plot was mowed to a uniform height o f 2” before treatment. A pre-treatment survey o f the experimental area was conducted and the bluegrass was found to be uniform in color and overall quality. The materials were applied using plastic coated containers as ‘shaker dispensers’. An application of 1 lb P (Triple Super P) and K (K2S 0 4)/1000 ft2 was made on May 17. Sequential applications were m ade on August 10. Rainfall was sporadic throughout the duration o f this trial and temperatures were unusually high. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. Visual quality and fresh clipping weight data were taken weekly from M ay 24 through October 11. Visual quality was assessed using a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 2 and 3). The mowing height for collecting clippings was 2" (Tables 4 and 5). Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis o f Variance (ANOVA) procedure. Least Significant Difference (LSD) means comparisons were used to assess fertilizer effects on bluegrass quality and clipping weights. There were no symptoms o f phytotoxicity on Kentucky bluegrass treated w ith the fertilizer products. On each data collection date, there were significant differences in bluegrass quality among the fertilizer products (Tables 2 and 3). Bluegrass quality responses to some o f the fertilizers were evident on May 24 (nine days after treatment), but quality improvement was slow er in response to other materials. The sequential applications o f Renaissance (Treatment 7), the Ringers fertilizer and the Toro products resulted in a rapid improvement in turf quality. The m ean visual quality was better than the untreated control in all fertilized plots except those receiving Renaissance at 1 lb N/1000 ft2. The best mean quality was achieved by bluegrass treated with com gluten meal, Renaissance, at 4.0 lbs N/1000 ft2 in split applications, R inger’s fertilizer, and the Toro products. Differences also were recorded on each data collection date for clipping weights among the fertilized plots. All o f the fertilizers significantly increased mean clipping weights when compared with the untreated control. Initial and sequential treatment with some o f the products resulted in rapid increases in clipping weights, while the response to other products was slower (Tables 4 and 5). The highest mean weights were for bluegrass treated with the Toro products, but grass treated with 62 Fertilizer Trials and Soil Studies Renaissance at 3.0 lb N/1000 ft2, Renaissance at 4.0 lb N/1000 ft2 in split applications, and the Ringer product had similar clipping weights. T able 1. The rates and application tim es1 o f the fertilizer products used in the 1995 Kentucky bluegrass fertilizer study. Yearly am ount (lbs N/1000 ft2) Initial A pplication (lbs N/1000 ft2) Sequential A pplication (lbs N/1000 ft2) 1 U ntreated control NA NA NA 2 Com gluten meal (10% N) 4.0 2 2 3 Sustane (5-2-4) 4.0 2 2 4 Renaissance (6-0-6)2 1.0 1 none 5 Renaissance (6-0-6)2 2.0 2 none 6 Renaissance (6-0-6)2 3.0 3 none 7 Renaissance (6-0-6)2 4.0 2 2 8 Ringers fertilize^ 10-2-6)3 4.0 2 2 9 M ilorganite (6-2-0) 4.0 2 2 10 Toro Product (12-3-9)4 4.0 2 2 11 Toro Product (22-2-3)4 4.0 2 2 Fertilizer 'initial applications were m ade on May 15 and sequential applications on August 10. 2Fairway Green's product. 3Ringer's fertilizer. 4Toro's fertilizer products. 63 July 27 7 6 6 3 *3 e3 a ¿ a vo oo r- vo ^ i s 2 > & r- ^ 8 7 3 * § VO o a 4.0 4.0 cr a , NA N/foOO^ s -a i>r-oot>r-r^^ Untreated control Com gluten meal (10% N) Sustane (5-2-4) 1 2 3 O a> o © o § CO w g CO CO § CO CO g CO _eo a a> 04 a S rr *o o pc a a S C4 VO r- V cs S3 Q > VO S» O >1 © u. » 3 ti p 1 <+-. »TN * co so % -M C/2 ^ S 3 *a IIII 0) 42 On 3 J£* I E o II cc O 0 *3 3 w ^ § VO g a o ^ -3 £ 33 0©, *0-• oO cn ♦00 Cfl ¿j on <+H tO 3 & 3 .S' S p p p o p o p 00 < ce §• j© 3 3 H, o 0T^ oO +-» CO 3 7 May 24 May 31 June 6 ■a Fertilizer Table 2. The visual quality1of Kentucky bluegrass (from May 24 to July 27) treated with natural organic and other fertilizers2._______________________________________ Fertilizer Trials and Soil Studies S 6« > is ¿3 I 1 a U co Oin CiO /— © VOv 9 vo' G" O p p p O <3 VO .§ © © o© o© t: O © a 3a a3 o 3a 3C vCO s vO s vvss •2C2O ^2© *3 *3 a© a© *3 a© *3 a© a00 PC PC PC P4 2 s o3 3o .3« *3 'O vs o § o o 2^ 3 3> j-T W -ti o O *§ *5 ra O O Q CO 3 & 2 H H J ^ 3 TT to VO r- On 00 9 CN vi CO i > 64 Fertilizer Trials and Soil Studies tO co 1*1,11) o ».S' H ^ g o > vmor o- rr -- uv n o rr -o omc cr N - r©- vo in Os Os CN O o 00 CN co ro CN rm CN CN VO i— i co , 00 Os CN i— i 1-H co CO vo rVO CN m 00 00 m rTf Os O m CO vo vo 00 vo o- co r—H CO 1-H CO CO in vo CN CO m CN Sf) OT S.Ei © U r- cn r-osC'-r'-oovor-cN co r- C"* g. 60 S a O — m o r-H vo Os CO VO ovO in in —' O in rc 'o-ooosioOoT©j -ocsO oT o rt > « oi ns ro-o~ovsoiin— o cc v^ © < co © tt cn ^ co ■n- —• o cNmcocNCNco'ifTi- tj- r-* CO o o G cc o *c CQ oc in 1 0 1 eg Os in — CO 1—1 CN CN — T—1 CN r* CO CN CN r— CN Os ’—1 vo — in oo — ^r o Os VO vo m CO in o o r - t ^ m r - e N m o c ^ T r o ' ^ J ' vo r—l vo VO & Tj - T j - Os v o mc ' - c Ni n Os c NCNc o co •—i in co Os VO in oo r00 m o vo 00 CN 00 Os m A u g 23 CN m n 1-H m CN CO CO r- rr- vo o m r- ■rr VO co co o o CN 00 Os CN CO m CN CN to o vo *“ 1 & CN in CN CN CN < vo CN G o a jg 0O8 Os 00 CN r00 CN ri—i CO in »— CO , 1—H CO CO 1—1 CO m CN co Os CN co in o CO Os OO CO ro rr vo ■rr - £ G § s §• tfa • H-h a g c8 c8 feb»n CO 1 « Po o i W) s 3 a* VO CN vo vo vo o o o VO vo^ VO o a> o o o o G G aG Qj O. 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Bingaman, Nick E. Christians, and David S. Gardner Primo IE was screened in single and sequential applications with and without urea to determine the circumstances that m ight produce a flush o f turf growth following the growth regulation period provided by this product. This study was conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. The experimental plot was a 10-year old stand o f'P ark' Kentucky bluegrass with a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) soil with an organic m atter content o f 3.5%, a pH o f 6.70, 6 ppm P, and 110 ppm K. This site was well-fertilized this spring with 0.5 lb N/1000 ft2 from sulfur coated urea (37-0-0) plus 0.5 lb N/1000 ft2 from urea (460 - 0 ). The experimental design was a randomized complete block with three replications and 3 ft barrier rows between replications. Individual plots were 5 x 5 ft. There were six treatments including an untreated control, a fertilized control that received Urea, and four combinations o f Primo IE with and without sequential applications and fertilizer (Table 1). For all applications, Primo IE was used at the label rate for Kentucky bluegrass o f 0.26 lb a.i./Acre (0.75 fl oz/1000 fit2). Urea (46-0-0) was used for all fertilizer treatments at 1 lb N/1000 ft2. Sequential applications o f Primo IE and applications o f urea were m ade four weeks after initial applications (4 WAT). Primo IE was applied using a carbon dioxide backpack sprayer equipped with #8006 nozzles and a spray pressure o f 20-25 psi. Urea was applied using plastic coated containers as ‘shaker dispensers’. In those plots receiving urea and Primo IE, the Primo was sprayed after the urea had been applied. Initial applications were made on June 7. Prior to application, the plot was mowed to a uniform 2” height and the turf was checked for overall uniformity. It was partly cloudy, 84° F with a slight breeze and the turf was dry. Sequential applications were made on July 7. Clipping weight data were taken on July 6 so the plot had a uniform height o f approximately 2” . It was 75° F and partly sunny with a slight breeze. Rainfall was sporadic for the duration o f this study and temperatures were unusually high. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing conditions. Visual quality rating and fresh clipping weight data were taken weekly from June 15 through August 16. Adjustments to the data collection schedule were necessary because o f rain events. Visual quality was assessed by using a scale o f 9 to 1: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality. Factors considered in the ratings were color, density, and uniformity (Table 1). The mowing height for collecting clippings was 2" (Table 2). Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) and the Analysis o f Variance (ANOVA) procedure to test the significance o f the treatment effects on the visual quality and clippings weights. Least significant difference (LSD) was used to compare means among the treatm ents. There were no visual quality differences among the treated and untreated plots until after the sequential applications on July 7. After this date, bluegrass treated with fertilizer at 4 WAT (Treatments 2, 4, and 6) exhibited better color and thickness than bluegrass not receiving urea (Table 1). 69 Fertilizer Trials and Soil Studies Clipping weights o f bluegrass treated with Primo IE were lower from June 15 through June 29. After the sequential applications o f Primo IE and urea, bluegrass in the fertilized control plots and in plots receiving only urea at 4 WAT (Treatment 4) showed a significant increase in clipping weights when compared with grass in the untreated control and in those plots treated with Primo IE at 4 W AT (Treatments 5 and 6). After July 21, there was a post inhibition stimulation o f growth in bluegrass treated with Primo IE and urea at 4 WAT. The clipping weights were similar to those from bluegrass treated w ith Primo IE initially and fertilized with urea at 4 W AT and the fertilized control plots (Table 2). Bluegrass in the fertilized control and in the plots treated with Primo IE initially and fertilized at 4 WAT (Treatment 4) produced the highest total clipping weights. Bluegrass in the untreated control plots, in plots receiving only an initial Primo IE application (Treatm ent 3), and in plots receiving Primo IE initially, and in combination with urea at 4 W AT (Treatment 6), had sim ilar total clipping weights. The lowest total clipping weights were recorded for bluegrass receiving Primo IE initially and sequentially at 4 W AT (Treatm ent 5). 70 Fertilizer Trials and Soil Studies p cd *Sh3 vo § CD S oc ^ • a 00 vo z §• > ^ o H 60 60 p ON 04 ON On O' »— ( 04 O' OC vn in t-H r~n O 00 vo tT vo ON O' f< oc vn ON CO O' 0- O' IO CO r—H vo tt cn O' O' P- Tf ON 0 < O60 60 P < p < Ü P o CJD OC VO Tf o ON 3 es p o o Oh 04 00 P + O VO ON 04 o ON O' 00 z 3 vn m vo 00 ON ON VO O' «— 1 vn On VO 3 II vo >v u T3 VO 00 z VO 3 P z 04 CD a* a CO _N 3£ w o £ t; < £ £ O' OC 04 04 in oc o 3 04 p 0 6Í CD S 3 w w w CD o s o s £ £ rr vn o s £ Ti­ n­ 04 ON CD H in oc OO O CO O CO ON O in 04 04 t—H C/5 00 t—H 00 3 h & H *n c CD in CO 04 0 CO 04 in 00 r-H OC 00 r—H CO oc in O' r—H 04 TT TT *P P »tí ^ V 0h N P & ^ 1 § I £* o J a] p •§ 3 3cd Ph’5605 cd r- 3o 1 S B c/5 c313 60 cd cS > vn *P. .3* 3 £ ’P CD z 0 CD 43 <« *§ g Tf p 00 > —> O < ON Vh O ^ > no 3 3 § in 0 II < O' >% E Cd .s 3 CO P P O T3 p 3 3 «n vo ON ^ c/5 _g 3o 00 00 ►—> c/2 •*2 VO VO VO vo vo ON 3 cd «-* o P 04 3►—» g£ oa ¿i 2 3 a> ON 04 cd 1> vo 04 CD vo vo TT . S'- CD S c (D O' vn 3 I 3 ON 3 cd 3 3 o "a cd P cr 04 co Ah 1 tn 04 3 0 p CN 3 Ah HÍ 1—4 P r- ON 3 a OC < o cd ON ON VO ON 60 P a* cd 5 T3 vo U o o p ’p o Uh Ah o £ P oo T3 0> 3o ¿2 P P g -e if 00 Z L —>«N ^ 71 1 3 3fo w w 3 o o 3 p E a p- <« ^ 3 3 - b 3 3 > 3 3 f< VL h w w •« ^ o !ss & __________________________________ 1 1 Plots were evaluated on a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality. ** Values are means of scores of 3 replicates compared with the untreated control. * 82 Environmental Research Table 3. The effect o f com gluten meal (CGM) and/or com gluten hydrolysate (CGH) on crabgrass __________ control in Kentucky bluegrass field plots.___________________________________________ Treatment Percent Crabgrass Reduction (%)* No. Rate o f CGM + CGH (lb/1000 ft2) Julv 14 July 21 August 18 Untreated control No CGM + 5 lb/ioOO ft1 CGH No CGM + 10 lb/1000 ft2 CGH No CGM + 15 lb/1000 ft2 CGH No CGM + 20 lb/1000 ft2 CGH 0 44 50 69 38 0 19 42 61 38 0 22 38 68 38 6 7 8 9 10 5 lb/1000 5 lb/1000 5 lb/1000 5 lb/1000 5 lb/1000 5 lb/1000 ft2 CGH 10 lb/1000 ft2 CGH 15 lb/1000 ft2 CGH 20 lb/1000 ft2CGH 44 25 49 38 44 48 19 23 42 47 44 24 4 36 31 11 12 13 14 15 10 lb/1000 10 lb/1000 10 lb/1000 10 lb/1000 10 lb/1000 ft2 CGM ft2 CGM ft2 CGM ft2 CGM ft2 CGM + 5 lb/1000 ft2 CGH + 10 lb/1000 ft2 CGH + 15 lb/1000 ft2 CGH + 20 lb/1000 ft2 CGH 25 69 69 50 44 38 62 57 48 33 19 53 59 40 50 16 17 18 19 20 15 lb/1000 15 lb/1000 15 lb/1000 15 lb/1000 15 lb/1000 ft2 CGM ft2 CGM + 5 lb/1000 ft2 CGH ft2 CGM + 10 lb/1000 ft2 CGH ft2 CGM + 15 lb/1000 ft2 CGH ft2 CGM + 20 lb/1000 ft2 CGH 19 50 44 6 69 24 43 52 19 67 10 40 59 26 74 21 22 23 24 25 20 20 20 20 20 ft2 CGM ft2 CGM + ft2 CGM + ft2 CGM + ft2 CGM + 56 19 44 50 25 52 19 43 57 24 48 23 41 54 53 26 Gardens Alive! CGM @ 20 lb/1000 ft2 44 34 28 1 2 3 4 5 ft2 CGM ft2 CGM ft2 CGM ft2 CGM ft2 CGM lb/1000 lb/1000 lb/1000 lb/1000 lb/1000 + + + + 5 lb/1000 ft2 CGH 10 lb/1000 ft2 CGH 15 lb/1000 ft2 CGH 20 lb/1000 ft2 CGH LSD(0.05)** NS NS NS * Values are means o f 3 replicates as compared with the untreated control. The untreated control had an average o f 27, 35, and 67 crabgrass plants in each plot on July 14, July 21, and August 18, respectively. ** Least significant difference was used to compare the statistical difference between means at 5% level. NS indicates that the difference between two means is not statistically significant. 83 Environmental Research 1995 Field Study Comparing the Efficacy of Five Different Corn Gluten Meal and Corn Gluten Hydrolysate Products for Crabgrass Control Dianna L. Liu and Nick E. Christians Three different com gluten meal (CGM) and two com gluten hydrolysate (CGH) products were evaluated for their efficacy as natural crabgrass control products in turf. This trial was located in an area of'Park' Kentucky bluegrass at the Iowa State University Horticulture Research Station. The soil in this experimental area is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content o f 3.1% a pH o f 7.2, 6 ppm P, and 110 ppm K. Three different CGM products and two CGH products were tested at 10, 15, 20, and 30 lb/1000 ft2 (Table 1). An untreated control was included as a comparison. A total of 21 treatments were randomly arranged and replicated three times. Individual experimental plots were 5 x 5 ft with 3 ft barrier rows between replications. All the treatments were applied on April 25, 1995. The CGM samples were applied with a hand-held shaker while the CGH samples were dissolved in an adequate volume o f water (Table 1) and sprayed by using a backpack carbon dioxide sprayer equipped with 3-XR TeeJet 8005 VS nozzles at a pressure of 25-30 psi. To evaluate the effect o f application timing on efficacy, four additional treatments of the CGH (sample #4) at 15 lb/1000 ft2 were added to each replicate for four consecutive weeks, i.e. sprayed on May 2, May 10, May 16, and May 23,1995. The treatments were watered-in with the irrigation system. Rainfall was sporadic throughout the duration of this trial and temperatures were unusually high in mid- to late summer. Supplemental irrigation was used to provide adequate moisture to maintain the grass in a good growing condition. Visual quality data were taken on June 8, June 13, June 20, and July 11. Visual quality was measured using a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1= poorest quality (Table 2). Crabgrass control was assessed by making visual estimations o f the percentage of crabgrass cover per individual plot. Percent crabgrass cover data were taken on July 14, July 21, and August 18,1995 and expressed as percentage o f crabgrass reduction (Table 3). Data were analyzed with the Statistical Analysis System (SAS) version 6.09 using the General Linear Model (GLM) procedure. Least Significant Difference (LSD) means comparisons were used to assess treatment effects on bluegrass quality and crabgrass control. Turf quality was significantly improved from the untreated control at the rates o f 10 lb/1000 ft2 or higher. The higher the application rates the better the turf quality. The gluten hydrolysate residue (sample #5) had the least effect on turf quality in all of the samples. The unusual results on crabgrass control for samples #1, #2, #3, and #4 were likely due to the wet, cool spring followed by hot, dry weather in mid- to late summer (July and August). These conditions favor crabgrass infestation. Based on the statistical analysis, there was a significant difference in the percentage of crabgrass reduction due to the treatments and replicates. Treatments 15, 22, 23, 24, and 25, which were 15 lb/1000 ft2 o f the whole gluten hydrolysate applied five consecutive weeks, displayed more crabgrass reduction than the untreated control. W hen compared with the untreated control, treatments 15, 22, 23, 24, and 25 had reductions o f 40%, 47%, 44%, 76%, and 81% respectively. In general, the treatments applied in May (Treatments 22, 23, 24, and 25) had better crabgrass control than the early application on April 25,1995. Treatment #25, which was applied on May 23, 1995, had the greatest crabgrass reduction o f all the treatments. Sample #5, which is the residue o f CGH, was seen to have very little effect on crabgrass control. From this study, we have learned that the timing o f application is crucial to have effective crabgrass control especially for water soluble CGH samples. 84 Environmental Research Table 1. Com gluten meal (CGM) and com gluten hydrolysate (CGH) samples and their rates used in _______ this study. Water Used Treatment* Material (ml) Sample** No. (grams/25 ft2) Rate (lb/1000 fit2) Untreated Control N/A 0 1 0 N/A 10 114 2 #i N/A 170 3 15 #i N/A 4 20 227 #i 341 N/A 5 30 #i 10 114 N/A 6 #2 N/A 15 170 #2 7 N/A 20 8 #2 227 N/A 30 341 9 #2 N/A #3 10 114 10 170 N/A 11 #3 15 N/A 12 #3 20 227 N/A 30 341 13 #3 114 1300 14 #4 10 1900 #4 15 170 15 2600 #4 20 16 227 3800 #4 341 30 17 1300 10 114 18 #5 1900 15 170 #5 19 2600 #5 20 20 227 3800 #5 30 341 21 1900 #4 15 170 22-25*** * All the treatments were applied on April 25, 1995, unless stated otherwise. All CGMs were applied in dry form by using ice cream containers as shakers. CGH was dissolved in H20 and applied using a backpack sprayer equipped with 3-XR TeeJet 8005VS nozzles at pressure 25-30 psi. ** #1 Granular com gluten meal from Grain Processing Corporation (GPC, Muscatine, 1A) #2 Powdered com gluten meal (GPC, Muscatine, IA) #3 Powdered com gluten (Gardens Alive!, Lawrenceburg, IN) #4 Whole gluten hydrolysate Code# 1616-62-5 (GPC, Muscatine, IA) #5 Gluten hydrolysate residue Code# 1616-62-9 (GPC, Muscatine, IA) *** Treatments #22-25 were the same as treatment #15, and were sprayed for four consecutive weeks to compare the timing effect. 85 Environmental Research Table 2. The effect o f com gluten meal (CGM) or com gluten hydrolysate (CGH) on Kentucky bluegrass visual quality*. Treatment Turf Quality ** Sample# Untreated Control No. 1 2 Rate (lb/10002) June 6 June 13 June 20 July 11 0 10 7 7 7 7 8 8 8 8 8 8 8 6 6 8 6 6 8 9 9 9 8 8 8 7 7 7 #1 #1 #1 #1 #2 #2 #2 #2 3 4 5 6 7 8 15 20 30 8 8 10 7 15 8 20 7 8 30 8 9 9 7 7 #3 10 7 #3 15 7 8 8 20 7 #3 8 8 13 #3 30 7 8 9 14 #4 7 10 7 7 #4 15 7 15 7 7 #4 7 16 20 8 8 #4 17 30 8 8 8 10 7 18 #5 7 6 7 #5 15 7 6 19 7 20 #5 20 7 7 #5 30 7 21 8 8 #4 22 15 8 8 8 #4 8 23 15 8 9 24 #4 15 9 9 9 #4 25 15 9 9 9 LSD (0.05) 1 1 1 Plots were evaluated on a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1= poorest quality. Values are means o f scores of 3 replicates compared against untreated control. 9 8 8 8 8 8 10 11 12 ** Table 3. 1 2 3 4 5 6 7 8 9 Sample# Untreated Control #1 #1 #1 #1 #2 #2 #2 #2 Rate (lb/10002) 0 10 15 20 July 14 8 8 8 8 8 1 July 21 August 10 0 0 0 39 5 27 38 27 23 35 39 11 29 32 16 34 10 0 0 15 14 50 20 0 0 0 8 19 5 24 30 30 10 11 12 ** 8 7 7 7 The effect of com gluten meal (CGM) or com gluten hydrolysate (CGH) on crabgrass control in Kentucky blegrass field plots. Treatment ...................................Percent^Crabgras s Reductmn(%)* No. * 7 7 7 0 10 #3 5 8 #3 15 0 9 12 20 #3 9 32 19 13 #3 30 37 36 42 14 #4 10 0 35 18 15 #4 54 15 50 69 16 #4 20 0 15 26 #4 17 30 14 8 26 18 #5 27 10 8 32 #5 15 16 19 0 0 20 #5 20 0 0 21 21 #5 30 4 5 0 47 22** #4 15 32 50 41 23** #4 23 15 50 24** #4 15 76 76 88 #4 80 15 87 81 25** LSD (0.05) 56 47 36 Values are means of 3 replicates as compared to the untreated control. The untreated control had an average percent crabgrass cover of 37,43, and 63% on July 14, July 21, and August 10, respectively. Treatments 22- 25 were applied 4 consecutive weeks after the initial application on April 24, 1995. 86 Environmental Research 1995 Corn Gluten Hydrolysate Weed Control Study Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Corn gluten hydrolysate was screened for efficacy as an annual grass and broadleaf natural product herbicide in turf. This trial is a long-term study started in 1995. It is being conducted at the Iowa State University Horticulture Research Station north of Ames, Iowa. The experiment is located in an area of 'Ram 1' Kentucky bluegrass. The soil in this experimental area is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content o f 3.1%, a pH o f 6 .7 ,4 ppm P, and 109 ppm K. The experimental design is a randomized complete block. Individual experimental plots are 5 x 5 ft and three replications were conducted with 3 ft barrier rows between replications. Com gluten hydrolysate was applied at 0 ,5 , 10, 15, and 20 lbs product/1000 ft2 (Table 1). These rates translate to 0.5, 1.0,1.5, and 2.0 lbs N/1000 ft2. All treated plots received one preemergence application in early spring. An untreated control was included for comparisons. A survey o f the experimental area was made prior to treatment and the bluegrass was uniform in color and overall quality. The hydrolysate was dissolved in water and applied using a carbon dioxide backpack sprayer equipped with #8006 nozzles at 30 psi. Application o f the materials was on April 17. The materials were watered-in with the irrigation system. The first post-application rainfall occurred on April 17. Rainfall was sporadic throughout the duration of this trial and temperatures were unusually high. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. The experimental plot was checked for phytotoxicity on April 18 and periodically throughout the season. Visual quality data were taken on May 12, May 25, June 7, June 21, and July 21. Visual quality was measured using a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 1). Crabgrass control was assessed by making visual estimations of the percentage of crabgrass cover per individual plot. Crabgrass control data were taken on July 6, July 21, and August 2 (Table 2). Broadleaf weed control data will be taken in the early spring of 1996. Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis o f Variance (ANOVA) procedure. Least Significant Difference (LSD) means comparisons were used to assess CGM effects on bluegrass quality and crabgrass control. No phytotoxic symptoms were detected on any treated bluegrass. Turf quality was improved by the hydrolysate as compared with the untreated control plots. Hydrolysate at 10,15, and 20 lbs product/1000 ft2 significantly increased the visual quality on May 25, June 7, and June 21 and the mean quality when compared with the untreated control and hydrolysate at 5 lbs product/1000 ft2 (Table 1). Crabgrass cover was less in bluegrass treated with hydrolysate at 10,15, and 20 lbs product/1000 ft2 when compared with hydrolysate at 5 lbs product/1000 ft2 and the untreated controls. Crabgrass populations were reduced 45, 56, and 66% by hydrolysate at 10,15, and 20 lbs product/1000 ft2, respectively (Table 2). Environmental Research Table 1. Visual Quality1 of Kentucky Bluegrass treated with Com Gluten Hydrolysate on April 17 for the 1995 Com Gluten Hydrolysate W eed Study. Material lbs product /1000 ft2 May 12 May 25 June 7 June 21 July 21 M ean Quality NA 7 6 6 6 5 6 1. Untreated control 2. Com gluten hydrolysate (10% N) 5 7 6 6 7 6 6 3. Com gluten hydrolysate (10% N) 10 7 7 7 7 7 7 4. Com gluten hydrolysate (10% N) 15 9 9 8 8 7 8 5. Com gluten hydrolysate (10% N) 20 9 9 8 9 7 8 NS 1 1 1 NS 1 LSD(a05) NS = not significantly different at the 0.05 level. 1 Visual quality was assessed with a scale o f 9 to 1: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality. Table 2. Percentage o f Crabgrass Cover in Kentucky Bluegrass treated with Com Gluten Hydrolysate on _________April 17 for the 1995 Com Gluten Hydrolysate W eed Study._______________________________ Percent Crabgrass Cover Material 1. Untreated control lbs product /1000 ft2 July 6 July 21 August 2 Mean Crabgrass Cover % Reduction in Crabgrass Cover NA 45 53 69 56 0 2. Com gluten hydrolysate (10% N) 5 32 47 66 48 14 3. Com gluten hydrolysate (10% N) 10 20 30 43 31 45 4. Com gluten hydrolysate (10% N) 15 12 25 37 25 56 5. Com gluten hydrolysate (10% N) 20 13 20 24 19 66 21 18 21 17 31 LSD(0.o5) 88 Environmental Research Corn Gluten Meal Crabgrass Control Study - Year Five Barbara R. Bingaman, Nick E. Christians, and David S. Gardner A study screening com gluten meal (CGM) for efficacy as a natural herbicide and fertilizer in turf was begun in 1991, and has been for five consecutive seasons on the same site. It is being conducted at the Iowa State University Research Station north o f Ames, Iowa. The experiment is located in an area o f 'Parade' Kentucky bluegrass. The soil in this experimental area is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 3.2% a pH o f 6.6, 9.2 ppm P, and 87 ppm K. Individual experimental plots are 5 x 5 ft with five treatments and three replications. The experimental design is a randomized complete block. Granular com gluten meal was applied at 0 ,2 ,4 , 6, 8,10, and 12 lbs N/1000 ft2 (Table 1). Com gluten meal is 10% N and these rates translate to 0, 20,40, 60, 80,100, and 120 lbs CGM/1000 ft2. All treatments were made to the same plots as in previous years. The CGM was measured into plastic coated ice cream containers that were used as 'shaker dispensers'. The CGM was applied in a single early spring preemergence application on April 13, 1995. The materials were watered-in with the irrigation system. The first post-application rainfall occurred on April 17. Rainfall was sporadic throughout the duration o f this trial and temperatures were unusually high. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. The plot was evaluated for phytotoxicity on April 15 and periodically throughout the growing season. Visual quality data were taken on July 21. Visual quality was measured using a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 1). Crabgrass control was assessed by making visual estimations o f the percentage o f crabgrass cover per individual plot. Crabgrass control data were taken on July 21, August 2, and August 10 (Table 2). Broadleaf weed control data were taken May 9,1996 (Table 4). Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis o f Variance (ANOVA) procedure. Least Significant Difference (LSD) means comparisons were used to assess CGM effects on bluegrass quality, crabgrass control, and dandelion and clover control. There was no phytotoxicity observed in the Kentucky bluegrass treated with CGM. There were significant increases in turf quality among the CGM treatments when compared with the untreated control (Table 1). The best quality was observed in turf that received either 60, or 80, or 100, or 120 lbs CGM/1000 ft2. Crabgrass populations were extremely high in 1995 due to wet conditions early in the germination period. Outbreaks o f crabgrass were found in treated plots that had either very low numbers or no crabgrass in 1994. W hen compared with the untreated control plots, however, significant levels o f crabgrass control were achieved with CGM in 1995. Significant differences in the percentage o f crabgrass cover were found between the treated and untreated controls on all collection dates (Table 2). The lowest percent cover was in bluegrass that received 60 lbs CGM/1000 ft2, but the control level was not different from that recorded for CGM at 40, 80,100, and 120 lbs/1000 ft2. Crabgrass cover was significantly reduced by CGM treatment at all but the 20 lbs/1000 ft2 level when compared with the untreated controls. A partial explanation o f this may be that this area had only 2 lbs N/1000 ft2 for the last 5 years and the turf is beginning to thin. Reductions were 88,93, 75, 75, and 84% for 40, 60, 80,100, and 120 lbs/1000 ft2 CGM, respectively. 89 Environmental Research The number o f crabgrass plants was significantly reduced in plots treated with CGM (40, 60, 80, 100, and 120 lbs CGM/1000 ft2) when compared with the untreated control. The least crabgrass plants were found in bluegrass that received 40 and 60 lbs CGM/1000 ft2, but the level o f crabgrass control was not different from that achieved by CGM at 80, 100, and 120 lbs CGM/1000 ft2. Reductions o f crabgrass numbers were 86, 88, 71, 75, and 82% in bluegrass treated with 40, 60, 80,100, and 120 lbs CGM/1000 ft2, respectively (Table 3). Comparisons can be made among the reductions in crabgrass cover data from previous years. Percentage reductions in 1995 were less than those recorded in previous years for each CGM treatment (Table 3). Reductions in dandelion and clover in CGM treated plots were first documented in 1994. Comparisons of the 1994 and 1995 data show that reductions o f dandelion and clover were less in 1995 (Table 4). Table 1. Visual Quality1 o f Kentucky Bluegrass treated with granular com gluten meal on April 17 for the long-term crabgrass study. Material lbs N/1000 ft2 lbs CGM/1000 ft2 July 21 1. Untreated control 0 0 6 2. Com gluten meal 2 20 7 3. Com gluten meal 4 40 8 4. Com gluten meal 6 60 9 5. Com gluten meal 8 80 9 6. Com gluten meal 10 100 9 7. Com gluten meal 12 120 9 1 LSD(0.o5) 1. 1 Visual quality was assessed with a scale o f 9 to 1: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality. Table 2. Percentage o f crabgrass cover in Kentucky Bluegrass plots treated with granular com gluten meal (CGM) on April 17 for the long-term crabgrass study. Percent crabgrass cover (%) Material lbs CGM July August August Mean % % Reduction /1000 ft2 21 2 10 Cover in Cover 1. Untreated control 0 28 24 45 25 — 2. Com gluten meal 20 17 18 29 16 36 3. Com gluten meal 40 4 3 6 3 88 4. Com gluten meal 60 2 2 2 2 93 5. Com gluten meal 80 8 8 8 6 75 6. Com gluten meal 100 8 9 8 6 75 7. Com gluten meal 120 7 4 5 4 84 9 15 19 10 40 LSD(0.o5) 90 Environmental Research T able 3. Comparisons o f the percentage o f crabgrass reduction in Kentucky bluegrass plots treated with _________ granular com gluten meal (CGM) in 1991 through 1995.__________________________________ Percent crabgrass reduction (%) lbs CGM lbs N /1000 ft2 /1000 ft2 1991 1992 1993 1994 1995 0 0 0 0 0 0 0 20 2 58 85 91 70 36 40 4 86 98 98 97 88 60 6 97 98 93 98 93 80 8 87 93 93 87 75 100 10 79 94 95 86 75 120 12 97 100 100 98 84 26 44 31 39 40 l s d (0.05) T able 4. Comparisons o f the percentages o f broadleaf weed reduction in Kentucky bluegrass plots treated with granular com gluten meal (CGM) in 1994 and 1995. Percent weed reduction (%) Clover lbs CGM /1000 ft2 lb sN /1000 ft2 Dandelion 1994 1995 1994 1995 0 0 0 0 0 0 20 2 81 56 71 49 40 4 90 64 100 77 60 6 98 93 100 89 80 8 100 76 98 96 100 10 94 84 100 98 120 12 90 93 100 100 48 50 65 NS LSD(0.o5) NS = not significantly different at the 0.05 level. 91 Environmental Research 1995 Corn Gluten Meal Rate Weed Control Study - Year One Barbara R. Bingaman, Nick E. Christians, and David S. Gardner Cora gluten meal (CGM) was screened for efficacy as a natural annual grass herbicide in turf. This trial is a long-term study started in 1995 that will be continued on the same area for several years. It is being conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa. The experiment is located in an area of'R am T Kentucky bluegrass. The soil in this experimental area is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 3.0%, a pH o f 6.7, 4 ppm P, and 109 ppm K. The experimental design is a randomized complete block. Individual experimental plots are 10 x 10 ft with five treatments and three replications. Com gluten meal was applied at four different regimes of single and split applications (Table 1). The annual rate for all treated plots is 40 lbs CGM/1000 ft2, which is equivalent to 4 lbs N/1000 ft2. The CGM treatments were: four applications o f 1 lb N/1000 ft2, split applications of 2 lbs N/1000 ft2, an initial application o f 3 lbs plus a sequential o f 1 lb N/1000 ft2, and an initial application o f 4 lbs N/1000 ft2. An unfertilized control was included for comparisons. A survey of the experimental area was made prior to treatment and the bluegrass was uniform in color and overall quality. Initial applications were made April 13. Sequential applications for Treatment 2 were made on May 30, August 10, and September 21. The split application for Treatment 3 and the sequential application for Treatment 4 were made on August 10. The CGM was applied using plastic coated containers as 'shaker dispensers'. The materials were watered-in with the irrigation system. Rainfall was sporadic throughout the duration of this trial and temperatures were unusually high. Supplemental irrigation was used to provide adequate moisture to maintain the grass in good growing condition. The experimental plot was checked for phytotoxicity after the initial and all subsequent applications. Visual quality data were taken May 12, 25, June 7, 21, July 6, and 21. Visual quality was measured using a 9 to 1 scale: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality (Table 2). Crabgrass control was assessed by making visual estimations of the percentage o f crabgrass cover per individual plot. Crabgrass control data were taken on July 6, 21, and August 2 (Table 3). Broadleaf weed control data were taken on May 9, 1996. Data were analyzed with the Statistical Analysis System version 6.06 (SAS Institute, 1989) using the Analysis of Variance (ANOVA) procedure. Least Significant Difference (LSD) means comparisons were used to assess CGM effects on bluegrass quality and crabgrass control. There were no phytotoxic symptoms detected on treated bluegrass. Visual quality was better for bluegrass treated with CGM treatments than for untreated bluegrass (Table 2). Bluegrass receiving a single application at 4 lbs CGM/1000 ft2, and grass treated with an initial application o f 3 lbs CGM/1000 ft2plus a sequential o f 1 lb CGM/1000 ft2, exhibited the best quality throughout the season. The best mean visual quality for the season was in bluegrass receiving an initial treatment o f 4 lbs CGM/1000 ft2. There was less crabgrass in plots treated with com gluten meal, but the differences among the treatments were not significant due to a high degree of variability among replications. Crabgrass cover was reduced 28, 45,44, and 54% , when compared with the untreated controls by Treatments 2, 3, 4, and 5, respectively (Table 3). 92 Environmental Research Table 1. Rates and timing1of application of com gluten meal for the long-term rate crabgrass study started in 1995. lbsN lbsN lbsN Yearly Yearly lbsN Material lbsN/1000 ft2 lbs CGM/1000 ft2 /1000 ft2 /1000 ft2 /1000 ft2 /1000 ft2 1. 2. 3. 4. 5. Untreated control Com gluten meal Com gluten meal Com gluten meal Com gluten meal NA 4 4 4 4 NA 40 40 40 40 NA 1 0 0 0 NA 1 2 3 4 NA 1 0 0 0 NA 1 2 1 0 1 Initial applications were made on April 13, sequential applications o f Treatment 2 on May 30, Treatments 2, 3, and 4 on August 10, and Treatment 2 on September 21. Table 2. Visual quality1of Kentucky bluegrass treated with powdered corn gluten meal for the long-term rate ________ crabgrass study started in 19952.______________________________________________________ Mean Yearly May 12 May 25 June 7 June 21 July 6 July 21 Quality Material lbs N/1000 ft2 1. 2. 3. 4. 5. Untreated control Com gluten meal Com gluten meal Com gluten meal Com gluten meal NA 4 4 4 4 LSDq.05 5 6 8 8 8 6 7 8 9 9 6 7 8 8 8 6 8 7 8 9 6 7 7 8 9 6 7 7 8 9 6 7 7 8 9 1 1 1 1 1 1 1 1Visual quality was assessed with a scale o f 9 to 1: 9 = best quality, 6 = lowest acceptable quality, and 1 = poorest quality. 2 Initial applications were made on April 13, sequential applications o f Treatment 2 on May 30, Treatments 2, 3, and 4 on August 10, and Treatment 2 on September 21. Table 3. Percentage of crabgrass cover in Kentucky bluegrass treated with com gluten meal for the long-term rate ________ crabgrass study started in 19951._______________________________________________________ __ Percent crabgrass cover 1. 2. 3. 4. 5. Material Yearly lbs N/1000 ft2 July 6 July 21 August 2 Mean Crabgrass Cover % Reduction in Crabgrass Cover Untreated control Com gluten meal Com gluten meal Com gluten meal Com gluten meal 0 4 4 4 4 17 10 4 8 5 28 28 20 22 18 39 22 22 17 16 28 20 15 16 13 0 28 45 44 54 NS NS NS NS NS LSDq.05 NS = not significantly different at the 0.05 level. 1Initial applications were made on April 13, sequential applications o f Treatment 2 on May 30, Treatments 2, 3, and 4 on August 10, and Treatment 2 on September 21. 93 Environmental Research Corn Gluten Meal/Pendimethalin Interaction Study - 1995 David S. Gardner, Nick E. Christians, and Barbara R. Bingaman Studies conducted at Iowa State University since 1985 have shown that com gluten meal applied to the soil has an inhibitory effect on the germination and establishment o f a variety o f weed species. These findings led to the issuance o f three U.S. patents and the release of the product called A-MAIZING LAWN for the pre-emergent control o f crabgrass in turf. An area o f current interest in developing CGM as a herbicide, is whether application, in combination with a sub-lethal rate of a synthetic herbicide, can result in either increased control o f crabgrass at the current recommended rate, or a reduction from the recommended rate. The purpose o f this study was to investigate the weed control o f com gluten meal combined with sub-lethal rates o f the dinitroanaline herbicide, pendimethalin. Three greenhouse studies and a field study were conducted during 1995. Greenhouse Studies The studies were conducted in the Iowa State University Horticulture Greenhouses. There were twenty treatments, including the control, that were applied to 4-inch black plastic pots arranged as a randomized complete block design with three rows o f pots per block. There were three replications per treatment. The pots were filled with a Nicollet field soil (fine-loamy, mixed, mesic Aquic Hapludoll). The soil surface area within the pots was 10.56 in2. Each pot was seeded by hand with large crabgrass (1994 ISU Horticulture Farm) at a rate of 0.3 grams per pot. A light coating of topsoil was applied after seeding. Granular com gluten meal (Grain Processing, Inc., Muscatine, Iowa) was applied by hand and Pendimethalin (LESCO Pre-M, LESCO, Inc.) dissolved in 2 ml o f water was applied using a m ist atomizer (DeVilbiss Co., Somerset, PA). There were four rates of com gluten meal that were combined with five rates of LESCO Pre-M (Table 1). The label rate o f LESCO Pre-M is 0.9 to 1.4 oz / 1000 ft2 (1.5 to 2.25 lbs a.i./1000 ft2). Data were collected as counts of living crabgrass plants 28 days after treatment. The data collected from the three experiments were pooled for the analysis . The data were analyzed using the General Linear Models procedure o f SAS (version 6.07). The least significant difference (LSD) test was used to compare the treatment means. In the greenhouse, the sub-lethal rate of pendimethalin was more effective in reducing crabgrass germination than the com gluten meal. Conditions in the greenhouse mimic those in the field, but there are two important differences between the two that effect the outcome o f this study. One, the pendimethalin was applied to bare soil. Since there was no interference due to a thatch layer, much less material was required. Second, is that com gluten meal was applied at the same time as the crabgrass seed and thus may not have had adequate time to disperse before germination. Field Study The field study was conducted at the Iowa State University Horticulture Research Station north o f Ames, Iowa on common Kentucky bluegrass turf. The soil was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with a pH of 5.95, an organic matter content of 2.2%, 9.7 ppm P, and 86 ppm K. There were twenty treatments, including the control, that were applied to 5 x 5 ft plots arranged as a randomized complete block design with two rows of ten plots per block and 2 ft barrier rows between blocks. There were three replications per treatment. Powdered com gluten meal (Grain Processing, Inc.) was applied on April 13. Pendimethalin (LESCO Pre-M) was applied on April 25 using a carbon dioxide backpack sprayer equipped with #8006 nozzles at 30 psi. There were four rates of com gluten meal that were combined with five rates o f LESCO Pre-M (Table 2). 94 Environmental Research Data were collected as estimates o f percent crabgrass cover on August 10. The data were analyzed using the General Linear Models procedure o f SAS (version 6.07). The least significant difference test (LSD) was used to compare the treatment means. In the field, increasing the rate o f com gluten meal reduced crabgrass cover as much as increasing the rate o f Pre-M, suggesting an additive effect when the products are applied in combination. The results suggest that application o f 30 lbs of CGM and 0.15 oz Pre-M/1000 ft2 provides the same control o f crabgrass as would either 20 lbs of CGM with 0.31 oz Pre-M/1000 ft2, or 10 lbs of CGM with 0.46 oz of Pre-M/1000 ft2. Control using higher rate combinations than these did not differ significantly from that of the three combinations stated above. Previous studies suggest that com gluten meal applied alone at 20 lbs/1000 ft2 provides 40 - 60% control of crabgrass during the first year; that control increases to > 85% in subsequent years. The results of these studies suggest that the applicator can improve control of crabgrass by applying pendimethalin at a sublethal rate in addition to com gluten meal. This may be advantageous to those who wish to use some organic products, but still desire nearly complete control of crabgrass during the first season of com gluten meal use. In subsequent years, com gluten meal alone might provide adequate control of crabgrass, or the combination with pendimethalin could be used to provide more effective control. This was the first year for the field study. Weather conditions during the 1995 growing season were ideal for crabgrass growth which resulted in higher than normal weed pressure. The field study will be repeated in the same location in 1996. A greenhouse study investigating the effects of combining com gluten meal with sub-lethal rates of other synthetic herbicides used in turf will be conducted in 1996. Results of these studies will be published in the 1997 Iowa Turfgrass Research Report. Table 1. Percent reduction in crabgrass survival by using different combinations of com gluten meal and LESCO _________ Pre-M tested in the greenhouse.___________________________________ ______________________ CGM Applied LESCO Pre-M Applied (oz/1000 ft") (lbs/1000 ft2) ............ 0 ........................0,15.....................0 3 1 ..................... 0.46..................... 0.61........... Reduction (%) 0 76.0 87.9 76.5 81.5 18.7 34.9 72.3 91.6 52.0 74.2 93.2 |LSD o.o5, 8 df. = 10.5% for differences among all of the treatments Values given are based on counts of living plants 28 days after treatment. 0 10 20 30 80.2 86.5 96.5 96.5 93.7 92.4 92.8 98.4 Table 2. Percent reduction in crabgrass cover from the control by using different combinations of com gluten meal _______ and LESCO Pre-M tested in the field during 1995.______________________ _____________________ CGM Applied LESCO Pre-M Applied (oz/1000 ft2) (lbs/1000 ft2) .............0 ....................... 0.15.....................0.31...................... ¿"46..................... 0.61.......... 0 10 20 30 |LSD o.o5,2 d.f. ■Reduction (%) 0 5.3 37.7 41.6 14.3 49.4 32.5 49.4 74.8 27.3 80.5 72.7 = 28.0% for differences among all of the treatments 95 45.4 68.8 84.4 75.9 42.8 62.3 77.4 94.1 Environmental Research Broadleaf and Grass Weeds Control with Corn Gluten Hydrolysate (Greenhouse Study) Dianna L. Liu and Nick E. Christians The objective of this study was to evaluate the effects o f com gluten hydrolysate (CGH) on plant survival of 19 monocotyledonous and dicotyledonous plants. The growth medium was prepared by placing soil in three-inch square plastic pots (Belten Plastics, St. Paul, MN) to a surface area o f 42.25 cm2 and a depth o f 4 cm. The soil was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 6.2%, a pH o f 7.73, 62 ppm P, and 229 ppm K. The eleven mononcotyledonous species were annual bluegrass (Poa annua L.), annual ryegrass ( multiflorum Lam.), bamyardgrass ( Echinochloacrusgali (L.) Beauv.), creeping bentgrass palustris Huds.), giant foxtail ( Setariafaberi Herrm.), green foxtail viridis (L.) Beauv.) crabgrass ( Digitariasanguinalis (L.) Scop.), orchardgrass ( glomerata L.), perennial ryegrass ( L o l i u m p e r e n n e L.), quackgrass (Agropyron repens (L.) Beauv.), Yellow foxtail ( lutescens (Weigel) Hubb.). The eight dicotyledonous species used in this study were black medic ( lupulina L.), buckhom plaintain ( Plantagolanceolata L.), common lambsquarters ( alb L.), curly dock ( Rumexcrispus L.), dandelion ( Taraxacumoffi oleracea L.), redroot pigweed ( Amaranthusretroflexus L.), velvetleaf (Abutilon theophrasti Medi The seeding rates used varied from 86 to 130 seeds per pot depending on species. All seeds were planted on the soil surface before powdered CGH was applied. Five rates o f CGH at 0, 1, 2 ,4 , and 8 g/dm2, ie 0, 20, 40, 80, and 160 lb/1000 ft2 were applied for each weed species. All 95 pots were placed on a mist bench for three to seven days depending on the germination rate o f a particular species. Once seeds in the untreated control pot reached a stable plant coverage, all pots were moved to a greenhouse bench. Temperature in the greenhouse was maintained in the range o f 65 to 90' F. The plants were subjected to drought stress for a period of five days. Plant susceptibility to CGH was assessed by the number of live plants in each pot (Table 1). The study was replicated three times between February 28 and April 2, 1996. The statistical design was a complete randomized block. Data were analyzed using the Statistical Analysis System (SAS) version 6.09 analysis of variance (ANOVA) procedure to estimate the significance o f CGH effects on plant survival. Least significant difference (LSD) tests were used to compare significanly different means. The CGH reduced the survival of all 19 species at all four application rates compared to the untreated controls. The higher the application rate, the greater the reduction. Buckhom plaintain, common lambsquarters, creeping bentgrass, and yellow foxtail were the m ost susceptible species exhibiting > 74% reduction at the lowest tested rate o f CGH (20 lb/1000 ft2). There was no difference in these four application rates for plant survival of buckhom plaintain, creeping bentgrass, and yellow foxtail. Bamyardgrass, black medic, curly dock, dandelion, giant foxtail, large crabgrass, purslane, and redroot pigweed were the second most susceptible plant species having > 50% reduction in plant survival at 20 lb/1000 ft2. Annual ryegrass, green foxtail, perennial ryegrass, and quackgrass were the least susceptible species with < 32% reductions at 20 lb/1000 ft2. At the application rate o f 40 lb/1000 ft2, all 19 species had > 50% reduction in plant survival. Black medic and buckhom plaintain had 100% reduction in plant survival, and common lambsquarters, creeping bentgrass, curly dock, giant foxtail, orchardgrass, purslane, redroot pigweed, and yellow foxtail had > 84% reduction compared to the untreated control. All species, except annual ryegrass, had 100% control at the highest application rate o f 160 lb/1000 ft2. 96 Environmental Research T able 1. The effect of com gluten hydrolysate on the survival o f 19 plant species. Plant species % Reduction in Plant Survival* 4 g/dm2 2 g/dm2 1 g/dmi 8 g/dm2 Annual bluegrass 45 72 91 100 Annual ryegrass 20 63 79 90 Bamyardgrass 51 75 100 100 Black medic 63 100 100 100 Buckhom plaintain 95 100 100 100 Common lambsquarters 75 85 100 100 Creeping bentgrass 82 97 100 100 Curly dock 61 89 100 100 Dandelion 48 58 95 100 Giant foxtail 56 86 96 100 Green foxtail 31 53 78 100 Large crabgrass 59 69 94 100 Orchardgrass 44 81 92 100 Perennial ryegrass 31 76 80 100 Purslane 61 92 100 100 Quackgrass 42 81 87 100 Redroot pigweed 69 88 99 100 Velvetleaf 49 77 95 100 Yellow foxtail 100 82 90 97 * The percentage is the degree o f reduction in plant survival compared to the untreated control. All the values are the average o f 3 replicates. LSD(0.05) = 22%. Data are expressed as percent reduction in plant survival from the control. 97 Turf Management The Effects of Common De-icing Chemicals on Turfgrass David D. Minner and Barbara R. Bingaman Runoff from de-icing products applied to walkways, driveways, etc. results in damaged and dead turfgrass borders. The purpose o f this study is to assess the level o f damage caused by several common de-icer products. Our approach was to simulate a brine runoff by spraying salt solution directly on turf plots throughout the winter and evaluating injuiy during the growing season. In addition, we applied the de-icers in granular form to turf plots. The first year of this study was conducted in the winter and early spring o f 1996 at the Iowa State University Research Station north o f Ames, Iowa The experimental plots were in an area of established common Kentucky bluegrass. Brine solution de-icer study: Individual experimental plots were 2 x 4 ft with three replications. Because of possible de-icer runoff, each individual plot was completely surrounded by a 1 ft border. Treatments containing Potassium chloride, 30% Urea + 70% CaCl2, 50% Urea + 50% CaCl2, 67% Urea + 33% CaCl2, Urea, Rock Salt, Safe Step (50% salt + 50% Potassium Chloride), M agnesium Chloride, and CaCl2 pellets were evaluated. A control was treated with only w ater for comparison. Treatment rates o f 2, 4, and 8 oz/yd2 were applied nine times during the winter to simulate typical amounts of product used in the ice melt industry (Table 1). This resulted in 18, 36, or 72 oz/yd2 o f total material applied for each treatment. M agnesium chloride is a hydrated salt and was applied at a higher rate (153 oz/yd2) to account for the extra water. Treatments were random ly placed within each replication. The de-icers were dissolved in water and applied using a carbon dioxide backpack sprayer. TeeJet flat fan EVS #8008, white nozzles were used at 45 psi. W indbreak ‘cages’ were employed to prevent drift o f the materials. No runoff or drift was observed after treatm ent differences became apparent. Nine applications were made beginning February 22 and ending M arch 19, 1996. A deer ‘cannon’ was placed to minimize browsing damage. Turfgrass plugs were taken from each plot in replication 2 after the 5th application of materials. Two plugs were taken for each treatment. The plugs were placed into pots and maintained on a m ist bench in the greenhouse until the grass began to green up. Granular de-icer study: Individual experimental plots were 2 x 2 ft with three replications. Because of possible de-icer runoff, each individual plot was completely surrounded by a 1 ft border. Treatments containing Potassium chloride, 30% Urea + 70% CaCl2, Urea, Rock Salt, Safe Step (50% salt + 50% Potassium Chloride), M agnesium Chloride, and CaCl2 pellets were evaluated. An untreated control was included for comparisons. Treatment rates of 1, 6, and 12 oz/yd2 were used to simulate typical amounts o f product used in the ice m elt industry (Table 2). Treatments were randomly placed within each replication. The amount of de-icer products equivalent to 10 individual applications was applied (Table 2). The materials were spread evenly over the plots. The products were applied March 15, 1996. A deer ‘cannon’ was placed to minimize browsing damage. Phytotoxicity and percent living plant material data were taken for the both the brine and granular studies on April 10 and May 9 (Tables 1 and 2). Phytotoxicity was assessed using a scale from 10 to 1: 10 = no injury and 1 = foliage completely brown. Percent living material was estimated as the percentage o f green plant material per plot. Some o f the plots, especially those treated with rock salt, were damaged by deer browsing. In these plots, the remaining plant material was considered to represent the entire plot in the data collection. On April 15, Kentucky bluegrass percent recovery data were taken on the plugs from the brine study that were maintained in the greenhouse. Recovery was assessed using a scale from 10 to 1: 10 = best recovery and 1 = no living plants (Table 1). Data were analyzed using the Statistical Analysis System (SAS) and the Analysis o f Variance procedure. Fisher’s least significant difference (LSD) tests were used to compare the effects o f the de-icers on turfgrass phytotoxicity and percent living material. 98 Turf Management "G en « tí .y o oí G E, 2 'S « T3 § *G O m r O ’—i i—i h r-i- Hoo\ OHf T) f nHi oFHr - 1 ^ > O o Oh C U V G o O e £ V-h C /3 O OC M (N vo vo m en ’S. es 2 > O O 3 N® o\ > o o (D Uh G ’-HroO'»-HcnO'’-HfnO' ’- Hmr^»~i mO' mo>»n’—«roo- tí 00 Ov 00 2 •S (L> 0> T5 Pi N 2 04 Tr ooo4Tj - ooo4^x( NTf cocNTr ooo4Tr oor 4Tf ooTr ai Lo4^oo c tí < ^2 tí O. ^ U o *T 2 ^ Oh £ OC ; E ë ,1 O 2 2 J? « (U> ^ vo On s ^ 8 S * S s S ü C /3 en e n e n v i v i u i ' 0 ' 0 ' o a i ¿ 2 D D D 2 2 2 < H 0 4 m T i - t n v o o o o o \ 0 ^ o 4 m ^ , ' n v o o o o a \ 0 ’H04mTr .2 > 1O (C L> B» O CG %C 2D O G „ X! 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WWWq q q ^jn .......... 66.60.m Ss Si $ £ a 3 3 3 <2&&£ £ £ S' S' S' ö ö o —< c N r o T r w o v o r ^ o o o N © —» c N r o T j - w o v o r ^ - o c o N © » —< cn I t— I t— I » — ( » - H r —( ^ —» r N C N C N 100 qq 5___________________________________________________________________________ CN CN r - L SD © 0000»—li—I L 2 __________________ ( X 9 ________________ 0 . 8 r o t ^ C N —< r ' - C N O O © © C N O O l ^ O O O O O < N O © ^ ro (N ^ (N CN -H cN Phytotoxicity was assessed using a scale from 10 to 1 with 10 = no injury and 1 = foliage completely brown. ^Percent living plant material was assessed as percentage of green plant material per plot. ........................... Phytotoxicity............................................... Total De-Icer product Rate applied April 10 May 9 Mean April 10 May 9 Mean _______________________________ oz/yd2_____ oz/yd2_______________________________________________________________________________ T ab le 2. Phytotoxicity and percent living green plant material data for field plots treated with de-icing products for the 1996 Granular De-Icer Study. Turf Management Turf Management Rubber Tire Particles as a Topdressing Amendment for High Traffic Grass David D. Minner The rubber tire recycling industry produces several grades, sizes, and shapes o f processed rubber. All recycled rubber is not the same. Suitable materials for athletic field use must be free o f all metal fibers and slivers, and must be of a size that is compatible with hollow coring and can easily filter into the turf canopy. Some rubber particles may contain nylon strands from “cord reinforced tires”. It is doubtful that the nylon will lim it plant growth, however, the effect of the nylon on water retention and plant growth is not known. To ensure a consistent rubber product only a trace o f nylon should be present. There are two distinct sources for rubber at this time. One is crumb rubber that comes from chipping whole tires, and the other is rubber buffings that comes from the retread industry when tire treads are ground before recapping. Processing and distribution o f crumb rubber is more advanced at this time and commercial rubber materials are available in the 1/4 inch and 2 mm (.08 in) size. The “coarse crumb” and “m edium crumb” materials used in this study are from the tire chipping and screening process (Table 1.). There has been very little effort in commercially producing screened rubber buffings for turf use. Consequently, this product is usually given away for the price o f shipping. “Buffings” are shreds of rubber that are ground directly from the intact tire before it is recapped with a new tread. Buffings have no metal or nylon cord since only the rubber tread is recycled. The particles range in size from 2 inches to 0.25 m m (about the size o f medium sand). Smaller particles are rounded but many are shreds that have a length to width aspect ratio o f approximately 5:1. Two buffing products have been screened for use in this study (Table 1.) A study was initiated in May, 1995 at the Iowa State University Horticulture Research Station, north of Ames, Iowa to evaluate various sizes o f “crumb” and “buffing” rubber for use as a topdressing material on high traffic grass areas. The purpose o f this study was to determine the maximum amount o f rubber that can be applied without causing reduced grass performance. On 6 May 1995 a mature stand o f ‘M idnight’ Kentucky bluegrass was mowed at a 1/2-inch height to remove most of the grass blades and then solid tine cored on 3-inch centers with 1/2-inch tines. All topdressing materials were then hand spread and raked into the plots that consisted of grass stubble and core holes. The sand topdressing and the non-treated control plots also received the same preparation of mowing and coring. Our interest is the longer term effect on grass performance as rubber accumulates in the surface mat and top two inches o f soil. Our proposed application rate o f 1.5 inches could not be accomplished in the first year. The maximum amount o f material that we felt could be applied was 0.75 inches. We plan on using a larger (3/4-inch) hollow tine to incorporate more rubber in 1996. Traffic treatments will also begin in the spring o f 1996. One o f the m ore interesting effects from rubber was noted on frozen ground. On 9 March 1996 sand topdressing and the no rubber control treatment produced a significantly harder surface (Gmax o f 349 and 241, respectively, with the 2.25 kg hammer) compared with the high rate of rubber topdressing (Gmax o f 107 to 116 for the 0.75-inch rubber topdressing treatments). 101 Turf Management Particle size analysis for sand, crumb ------- -rubber, and ----- buffings rubber used as topdressing. T able 1. Sieve M esh Size D iam eter mm Sand Coarse Crumb Medium Crumb Medium Buffing Course Buffing 1/4 in 6.3 0.0 0.0 0.0 0.0 0.0 Fine Gravel 10 2.0 0.4 85.0 23.7 4.5 13.9 Very Coarse 18 1.0 1.5 13.4 56.6 50.6 79.9 Coarse 35 0.5 17.2 0.5 9.1 35.1 6.1 Medium 60 0.25 55.7 0.4 7.1 7.7 0.1 100 0.15 19.1 0.1 2.4 1.6 0.0 <100 <0.15 4.2 0.1 1.0 0.3 0.1 Gravel Fine Very Fine T able 2. Treatment schedule for various “crumb” and “buffing” rubber materials applied as __________ topdressing to a mature stand of ‘M idnight’ Kentucky bluegrass.________________ (in.) Amount Applied May 6, 1995 (in.) Am ount Applied Sept. 11, 1995 (in.) Total As O f May 1, 1996 (in.) 0.75 .38 -- .38 1.50 .38 .37 .75 0.75 .38 — .38 1.50 .38 .37 .75 0.75 .38 — .38 1.50 .38 .37 .75 0.75 .38 — .38 1.50 .38 .37 .75 1.50 .38 .37 .75 — — — — Proposed Rate T re atm e n t 1. Coarse crumb 2. 3. Medium crumb 4. 5. Medium buffing 6. 7. Coarse buffing 8. 9. 10. Sand C ontrol 102 Turf Management Table 3. Surface hardness data from 0.05 and 2.25 kg hammers for various rubber particle __________ topdressing treatm ents.____________________________________________________ 2.25 kg Hammer 0.05 kg Hammer T re atm e n t Source Rate (in) 9/22/95 3/9/96* 3/12/96 4/17/96 3/9/96* 3/12/96 4/17/96 1. Coarse crumb 0.38 66 148 101 67 185 86 54 2. Coarse crumb 0.75 55 109 78 63 110 75 47 3. Medium crumb 0.38 68 165 110 67 200 89 54 4. Medium crumb 0.75 60 126 83 60 116 80 50 5. Medium buffing 0.38 64 129 100 60 192 100 53 6. Medium buffing 0.75 56 121 80 57 107 86 50 7. Coarse buffing 0.38 69 113 107 66 185 94 54 8. Coarse buffing 0.75 61 104 84 60 112 85 55 9. Sand 0.75 74 370 102 77 349 65 59 — 74 162 115 63 241 110 55 5 56 12 8 65 NS 4 10. C ontrol LSD(o.os) *Frozen ground conditions. Table 4. T urf color, grass quality, cushion, percentage sand topdress or rubber showing, and grass density for Kentucky bluegrass topdressed with various rubber materials on 22 September 1995. T reatm entSource Rate (in) Grass c o lo r1 Grass quality2 Cushion3 % Topdress or rubber showing4 Grass densitys 1. Coarse crumb .38 8.0 8.7 5.7 0.0 8.0 2. Coarse crumb .75 8.3 9.0 9.3 5.0 8.3 3. Medium crumb .38 6.7 7.7 5.0 0.0 8.3 4. Medium crumb .75 8.7 8.7 9.7 3.3 8.3 5. Medium buffing .38 8.7 9.3 7.3 0.0 8.7 6. Medium buffing .75 8.3 8.7 9.3 8.3 8.3 7. Coarse buffing .38 8.7 9.7 6.7 0.0 8.7 8. Coarse buffing .75 6.7 7.3 10.0 23.3 7.3 9. Sand .75 9.0 8.0 4.0 15.0 8.0 8.7 9.3 5.3 0.0 9.3 NS NS LSD(0o5) "H; ~ color was rated using a 10 to 1 scale: 10 = darkest green. ‘Grass 0.7 10.5 NS 10. C ontrol — 2Grass quality was rated using a 10 to 1 scale: 10 = best quality. 3Cushion was rated on a 10 to 1 scale: 10 = most cushion. 4Percent topdress or rubber showing was recorded as % of plot. 5Grass density was rated using a 10 to 1 scale: 10 = highest density. NS = not significantly different at the 0.05 level. 103 Ornamental Studies Growth and Development of Three Container-grown Deciduous Shrubs Started from Bare-root and Potted Liner Stock Jeffery K. lies Background and Justification Rewholesalers, garden centers, and other sellers of woody ornamental plants routinely receive bareroot nursery stock in late winter or early spring that is potted and sold later in the season. But bareroot plants are sometimes slow to establish in containers which makes transplanting difficult, particularly when sold during the busy spring and early summer months. Potted liners that come with well-developed root systems show potential for shortening the production cycle, perm itting the development of higher quality plants with better developed root systems sooner in the season. Anecdotal reports describing superior growth and improved visual quality o f containerized potted liners abound, however, no scientific studies comparing potted liners potted into containers vs. conventional bare-root/container-grown stock have been conducted. O b jective (1) Monitor shoot and root growth of three woody shrub species as influenced by nursery stock type and size, and container size, throughout two growing seasons. M aterials and M ethods The study was designed as a randomized complete block with three replications. In April, 1996, bareroot and potted liner plants of Cornus sericea 'C ardinal', Spiraea x bumalda 'G oldflam e', and Syringa x prestoniae 'Jam es M acFarlane' were obtained from Sherman Nursery Co., Charles City, Iowa, and potted as described below: Cornus sericea 'Cardinar Spiraea x bumalda 'Goldflam e' Syringa x prestoniae 'James MacFarlane' 3 1/2” potted liner (12 into 2 gal. containers) (12 into 3 gal. containers) 3 1/2” potted liner (12 into 2 gal. containers) (12 into 3 gal. containers) 3 1/2” potted liner (12 into 2 gal. containers) (12 into 3 gal. containers) 4-6" bare-root (12 into 1 gal. containers) (12 into 2 gal. containers) 6-9" bare-root (12 into 1 gal. containers) (12 into 2 gal. containers) 4-6" bare-root (12 into 1 gal. containers) (12 into 2 gal. containers) 6-12" bare-root (12 into 2 gal. containers) (12 into 3 gal. containers) 9-12" bare-root (12 into 2 gal. containers) (12 into 3 gal. containers) 6-12" bare-root (12 into 2 gal. containers) (12 into 3 gal. containers) Plant height and width, and shoot and root dry weights will be taken from representative samples on 1 June and September, 1996, and 1 June and September, 1997. 104 Ornamental Studies Effect of Several Organic and Inorganic Mulches on Tree Growth and Soil Properties Jeffery K. lies Background and Justification Mulching ornamental plants in the landscape with organic materials is enthusiastically endorsed and practiced by many green industry professionals. Yet several actual or perceived problems associated with the use o f mulch (unacceptable appearance, lack o f stability, potential fire hazard, rapid decomposition, etc.) have prompted m any to use inorganic or synthetic mulches. But fears that materials like rock, gravel, and crushed brick may cause potentially injurious high temperatures both above and below inorganic mulches, alkalinization o f the soil, and mechanical injury to the stems of plants have caused m any landscape and tree-care professionals to question the use of these and other inorganic materials. To date, there have been no studies that have directly compared the effects of inorganic and organic mulches on tree growth and associated soil properties. O b jective (1) To evaluate and compare the effects o f inorganic and organic mulches on several soil properties and growth of two tree species. M aterials and M ethods Bare-root, 4 to 6-foot branched Acer rubrum 'Fairview Flam e' and Tilia cordata 'O lym pic' were planted at the Iowa State University Horticulture Research Station in April, 1996. The experimental design was a completely randomized block with five replications. Mulch treatments (wood chips, shredded bark, pea gravel, crushed brick, and 1 1/2 inch river rock) 3 inches deep and in 5-foot squares around each tree, and an unmulched weed-free control, were randomly assigned to each tree species in each block. Organic mulches were placed directly on bare ground while inorganic mulches were underlaid with spunbonded polypropylene fabric. Tree growth measurements (shoot growth and caliper) will be taken in September 1996 and 1997. Soil moisture, pH, and temperature will be monitored weekly (during the growing season) in 1996 and 1997. This study was funded in part by a grant from the International Society o f Arboriculture. 105 Ornamental Studies Effect of Post-frost Pruning on Winter Hardiness of Selected Garden Chrysanthemums Jeffery K. lies Background and Justification Pruning aboveground tissues back to the plant crown in preparation for winter is a common cultural practice for garden chrysanthemums (Dendranthemax grandiflorum). Bu suggest pruning immediately before the onset o f low temperatures may be responsible for predisposing plants to winter injury. In fact, researchers in Germany found several species o f garden chrysanthemums suffered considerable winter injury i f they were "cut back" in late fall. Unfortunately, additional data, either concurring or disagreeing with the study in Germany, are not available. Therefore, this research sought to ameliorate the information deficit by testing the cultural practice o f pruning back garden chrysanthemums to the ground before the onset o f low winter temperatures. O b jective (1) To evaluate the effect of pruning nineteen species o f garden chrysanthemums in Novem ber and December on winter survival. M aterials and M ethods Rooted cuttings o f nineteen chrysanthemum cultivars were obtained from Yoder Brothers, Inc., and field-planted in a randomized complete block design with five replications on 1 June, 1995. Pruning treatments were: (1) plants pruned to 1" above the crown on 1 November, 1995; (2) plants pruned to 1" above the crown on 1 December, 1995; and (3) plants not pruned. Survival percentages and regrowth dry weights will be taken 1 June, 1996. Chrysanthem um Cultivars Used in the Study 'B aby Tears' 'B arbara' 'B ra v o ' 'C h ristin e' 'D ark Trium ph' 'D ebonair' 'D o n n a ' 'G renadine' 'G oldm ine' 'Jennifer 'Jessica' 'L in d a ' 'L y n n ' 'M eg an ' 'R aquel' 'S h elly ' 'T a rg e t' 'T r a c y ' 'T riu m p h ' 106 Ornamental Studies Does Premature Branch Removal and Improper Pruning Predispose Trees to Sunscald Injury? Jeffery K. lies Background and Justification Sunscald, occurring in both summer and winter, has been reported as a major problem for shade trees in northern locations. Thin- and/or smooth-barked deciduous tree species such as birch, maple, linden, ash, and crabapple seem to be m ost susceptible, however, sunscald has even been reported on some evergreen species. Numerous materials have been tested and used to prevent sunscald injury in the Midwest. But lately, researchers in the Eastern United States have recommended the practice of trunk wrapping be discontinued. Their reasons for this decision are: (1) wraps prevent photosynthetic tissues in the bark of young trees from trapping the sun's energy, thereby reducing the trees ability to manufacture sugars and other important compounds; (2) wraps placed over wounds and improperly pruned branches create unnaturally m oist conditions that encourage fungal and bacterial growth on these wounds; (3) if left in place too long, they may girdle and injure the trunk; (4) the cozy environment created by wraps, may actually encourage insect activity; and (5) they are unsightly if installed and then forgotten. In addition, there is very little scientific evidence showing trunk wraps prevent sunscald injury. However, climatic conditions during winter in the Eastern U.S. are dramatically different than conditions in the Midwest where higher light intensities, and rapidly changing temperatures seem to favor the incidence o f sunscald. Therefore M idwesterners have been reluctant to abandon the practice o f trunk wrapping. Some theorize that regardless o f whether a tree is wrapped or not, careless acts or ill-advised tree care practices like wounding, flush-cut pruning, and/or removing too m any branches, particularly those lower branches along the trunk, at time of planting can predispose trees to sunscald injury. Unfortunately, studies have not been conducted that would help the landscape manager make informed decisions about how to prevent sunscald injury. O b jective (1) To evaluate the effects of premature branch removal and flush-cutting on incidence of sunscald injury on two tree species. M aterials and M ethods Bare-root, 4 to 5 foot branched Acerxfreemanii 'A rm strong' and cordata 'June B ride' were planted at the Iowa State University Horticulture Research Station in April, 1996. The experimental design was a completely randomized block with five replications. Treatments were randomly assigned to each tree species in each block and were: (1) lowest pair o f branches removed at planting using recommended pruning practices; (2) lowest and next lowest pair o f branches removed at planting using recommended pruning practices; (3) lowest pair o f branches removed at planting using flush-cut technique; (4) lowest and next lowest pair o f branches removed at planting using flush-cut technique; and (5) no pruning done at planting. Tree height, trunk diameter, and shoot growth measurements will be taken on 1 September 1996 and 1997, and trees will be continuously monitored for evidence o f sunscald injury. 107 Ornamental Studies Elms on the Comeback Trail Jeffery K. lies Introduction Dutch elm disease (DED) caused by the fungus Ophiostoma ulmi, is one o f the m ost destructive plant diseases of the 20th century, and it rem ains a threat to American elms ( americana) even today. From the initial stand o f infected trees in the Ohio River Valley in 1932, the disease spread outward at a rate o f about 50 miles per year. And by the mid-1980's, the disease that became known as "the cancer o f the tree world" had left its devastating calling card in practically all o f the United States and southern Canada. Countless hours and dollars have been spent protecting existing American elms and developing effective strategies and techniques to control DED in North America and Europe. Proven or potentially useful DED control measures include: (1) eliminating breeding sites for the predom inant vector of DED, the European elm bark beetle ( Scolytus), (2) reduc with well-timed insecticide applications or by attracting beetles to "trap trees" treated with herbicide, and (3) preventing infection through the use o f injected fungicides, or injecting the natural bacterium Pseudomonas syringae which is antagonistic to the fungus causing DED. But because o f growing anti-pesticide (synthetic or naturally-occurring) sentiment, and/or the prohibitive cost o f implementing many o f the aforementioned control strategies, researchers have redirected their efforts to developing disease tolerant or resistant elms. European and Asiatic elms have played a significant role in the breeding, selection, and cultivar release efforts, but recently greater emphasis has been given to breeding and selecting American elms. The goal of finding or creating a disease tolerant American elm seemed improbable 20 years ago, but hopes have been revived with the release by the USDA o f two cultivars showing high levels o f DED tolerance. New Am erican Elm Cultivars The new American elm cultivars, 'V alley Forge' and 'N ew H arm ony', are products o f the U.S. National Arboretum tree genetics program and have demonstrated high levels o f tolerance to both aggressive and non-aggressive strains o f the fungus causing Dutch elm disease. Tolerance to DED is characterized by reduced wilting and crown dieback after fungal inoculation. In fact, according to Dr. Denny Townsend, these trees have the ability to recover from DED infection even after symptom expression. But it is important to remember that neither tree is completely immune to DED. O f the thousands of American elms screened, 'V alley Forge' has shown the best tolerance to DED. The tree has an upright, arching, broadly vase-shaped branching structure with a full, dense canopy o f leaves. Asexually produced progeny from the original parent tree are 26 feet tall with an average crown spread o f 30 feet after 12 growing seasons. Sum m er leaves are green, turning yellow in autumn. The bark is typical of the species, with grayish, flat-topped ridges separated by diamond­ shaped fissures. 'V alley Forge' is considered hardy in USDA zones 5 through 7. W hile not as disease tolerant as 'V alley Forge', 'N ew H arm ony' still ranks in the top three among the thousands o f American elms subjected to intensive inoculation with the DED fungus. The parent tree o f 'N ew Harm ony' displays a broad, vase-shaped crown and has grown approximately 68 feet tall and 72 feet wide. Leaf and bark characteristics are similar to those o f 'V alley Forge', but because of its acceptable performance in Minnesota, 'N ew H arm ony' is considered hardy in USDA zones 4 through 7. 108 Ornamental Studies The combination o f environmental adaptability, Dutch elm disease tolerance, and highly-prized vase­ shaped crown will make these selections extremely popular, however, it will probably take a number of years before these trees become commonplace in nurseries and retail garden centers. In the meantime, tree managers should consider the many commercially available hybrid elms for augmenting and diversifying the municipal tree population. Some o f the more important introductions are described in the following paragraphs. H ybrid Elm Selections 'A ccolade' ( usjapónica x Ulmus lm U )w ilsona- Also known as was released by the M orton Arboretum, Lisle, Illinois. The tree displays a handsome vase-shaped canopy, deep green glossy leaves, has shown resistance to DED, elm leaf beetle, and leaf miner, but only moderate tolerance o f urban soil conditions such as clayiness and seasonal wetness. 'C athedral' ( Ulmuspumila x Ulmus japónica) - One o f several excellent cultivars developed by Smalley and Lester at the University o f Wisconsin. 'C athedral' has demonstrated good tolerance to DED, experiencing only branch tip injury when infected with the fungus. The tree has a broad vase shape, m edium to light green leaves in summer and yellow fall foliage. In addition, 'C athedral' is highly tolerant to Verticillium wilt and is resistant to attack by the elm leaf miner. 'Frontier' ( Ulmuscarpinifolia x Ulmus parvifolia) -Rele has demonstrated a high degree o f resistance to DED, moderate resistance to elm leaf beetle, and high tolerance to the phytoplasma-caused elm yellows. Emerging leaves in spring are red, gradually changing to yellow-green in summer, finally turning red-purple in autumn. 'Frontier' becomes pyramdial instead of vase-shaped as it matures, however, it still should make a desirable street, park, landscape, or highway tree. Because it has sustained severe low temperature injury in Minnesota, 'F rontier' is considered reliably hardy only through USDA hardiness zone 5. 'H om estead' ( Ulmuspumila x complex hybrid from the Netherlands elm breeding program Another USDA release, 'H om estead' has a symmetrical, somewhat pyramidal crown that becomes arching as the tree ages. Its dark green summer leaves turn golden-yellow in fall and the growth rate is reportedly rapid. 'H om estead', best used in USDA hardiness zones 5 through 8, is considered highly resistant to DED, but is susceptible to elm leaf beetle. 'In d ep en d en ce' ( Ulmusamericana 'M oline' x Ulums americana W 185-21) - 'Indepen is one o f six clones that comprise the much heralded American Liberty multiclone variety. Patented by Smalley and Lester (Univ. o f W isconsin, Madison), 'Independence' develops an upright, vase-shaped crown typical of the species and has demonstrated tolerance to DED, but may be quite susceptible to elm yellows. 'P atriot' ( Ulmus'U rban' x Ulmus wilsoniana 'Prospector') - Developed by A.M. Townsend at the U.S. National Arboretum and released by the USDA, 'P atriot' has a moderately vase-shaped crown, resem bling a more upright American elm. It has shown a high level of resistance to DED, high tolerance to elm yellows, and reduced susceptibility to the elm leaf beetle. 'P atriot' is adapted to a wide variety o f soil conditions, grows best in full sun, and is considered cold hardy through USDA hardiness zone 4. 'Pioneer' ( Ulmusglabra x Ulmus carpinifolia) - 'P ioneer' is a vigorous, fast-growing USDA selection with large, dark green leaves and a globe-shaped crown. Hardy in USDA zones 5 through 8, it has proven resistant to DED and elm yellows, but elm leaf beetle feeding may be problematic. Because o f its broad, spreading habit, 'P ioneer' is best suited to spacious grounds like those found in parks, g o lf courses, and large commercial properties. 109 Ornamental Studies 'P r o s p e c to r' ( Ulmus ilsona) - This seedling selection was released in 1990 by the USDA w 'Prospector' elm has an American elm-like vase-shaped crown but its branches become pendulous at a much lower height. Newly expanding leaves are orange-red, but gradually darken to green, finally turning yellow in autumn. 'Prospector' is resistant to DED, tolerant to elm yellows, resistant to elm leaf beetle, and is considered adaptable in USDA hardiness zones 4 through 7. 'R e g a l' ( usC' om m elin' x Ulmus 'H oersholm iensis') - Selected at the University o f lm U W isconsin, 'R eg al' develops a strong central leader with an upright or colum nar growth habit when young, becoming more ovate with age. Leaves are dark green in summer, show no appreciable fall coloration, and because they are rather sparsely borne, cast a honeylocust-like light shade that makes possible the successful culture o f turfgrass in the vicinity o f the tree. 'R egal' is considered highly resistant to DED and Verticillium wilt, and is hardy in USDA zones 4 through 7. 'S a p p o ro A u tu m n G o ld ' ( Ulmuspumila x Ulmus japonica) - Released by the Un W isconsin in 1973, this elm has demonstrated high resistance to DED and tolerance to Verticillium wilt. 'Sapporo Autumn G old' displays vigorous growth, is quite tolerant o f urban stresses, and can be utilized in USDA hardiness zones 4 through 8. The tree is upright and irregular when young, becoming somewhat vase-shaped with age. And as the cultivar name suggests, autumn leaves are handsome golden-yellow. Over the past 30 to 40 years, plant breeders have spent considerable time, effort, and resources searching for elms having resistance to DED and other pests, and possessing the graceful crown architecture of the revered American elm. The recent release o f Ulmus americana "Valley Forge' and 'N ew Harm ony', and the improved availability o f many excellent hybrid elms is certain to spark renewed interest for elms of all kinds. But those responsible for making tree selection decisions must temper their understandable enthusiasm for these and future elm introductions. Establishing largescale monocultures or overusing any tree species would be a tragic and ill-advised repeat o f history. 110 Introducing Iowa State University Personnel Affilliated with the Turfgrass Research Program Barbara Bingam an, Ph.D. Postdoctoral Research Associate, Horticulture Department D oug C am pbell Research Associate, Horticulture Department Nick C hristians, Ph.D. Professor, Turfgrass Science Research and Teaching Horticulture Departm ent Jim Dickson Field Manager, Horticulture Department David Gardner Graduate Student and Research Associate Horticulture Department M.S. (Christians) Jason G ates Undergraduate Honors Student, Horticulture Department M ark G leason, Ph.D. Associate Professor, Extension Plant Pathologist Plant Pathology Departm ent Clinton H odges, Ph.D. Professor, Turfgrass Science Research and Teaching Horticulture Departm ent Jeff lies, Ph.D. Assistant Professor, Extension, Nursery Crops/Omamentals Horticulture Departm ent John Jordan Field Technician, Horticulture Department M ike K askey Field Technician, Horticulture Department Dianna Liu, Ph.D. Postdoctoral Research Associate, Horticulture Department David M inner, Ph.D. Associate Professor, Turfgrass Science Research and Extension Horticulture Departm ent Jason M anfull Field Technician, Horticulture Departm ent Scott M iller Field Technician, Horticulture Department Richard M oore Superintendent, Horticulture Research Station Steve Nelson Field Technician, Horticulture Departm ent Gary Peterson Commercial Horticulture Specialist J e ff Salm ond Graduate Student and Research Associate Horticulture Department M.S. (Minner) Loren Stephens, Ph.D. Associate Professor, Genetics, Tissue Culture, Ornamental Horticulture Departm ent 111 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 T urf Equipment Company and Cushman T urf for providing a Cushman Turfgrass Truckster and Ryan GA30 aerifier; to Tri-State T urf and Irrigation for providing a Greensmaster 3000 Triplex Greensmower and a Groundsmaster 325D rotary mower; and, to Great American Outdoor for providing a John Deere 2243 Triplex Greensmower for use at the research area. Agr-Evo USA Company 5967 N. Winwood Drive Johnston, IA 50131 Enviro-Gro Technologies PO Box 5036 Lancaster, PA 17601-0036 Heatway 3131 W. Chestnut Expressway Springfield, MO 65802 AIMCOR-Profile One Parkway North Deerfield, IL 60015 Fairway Green 5275 Edina Industrial Blvd. Edina, MN 55435 Hunter Industries, Inc. 1940 Diamond St. San Marcos, CA 92069 American Hoechst Corporation Agricultural Chemicals Department Route 1 - Box 7 Brownsdale, MN 55918 Ferris Industries, Inc. PO Box 910 Vernon, NY 13476 Iowa Golf Course Superintendents Association Big Bear Turf Equipment Company 10405 T Street Omaha, NE 68127 Gardens Alive! 5100 Schenley Place Lawrenceburg, IN 47025 Iowa Turfgrass Institute Glen Oaks Country Club 1401 Glen Oaks Drive West Des Moines, LA 50266 Kempkers Greens Mix RR 339 Eugene, MO 65032 Golf Course Superintendents Association of America 1421 Research Park Drive Lawrence, KS 66049-3859 LESCO Incorporated PO Box 10915 Rocky River, OH 44116-0915 Ciba Corporation Agriculture Division Greensboro, NC 27049 Coron Corporation PO Box 198 Souderton, PA 18964 Cushman Turf 5232 Cushman Lincoln, NE 68501 Frost-B-Gone Pelham, NH 03076 Gowan Inc. Lititz, PA 17543 Iowa Professional Lawn Care Association Iowa Sports Turf Managers Association Lyman-Ritchie Sand & Gravel 4315 Cuming Street Omaha, NE 68131 Grain Processing Corporation PO Box 349 Muscatine, IA 52761 McAninch Corporation West Des Moines, IA Grace Sierra PO Box 4003 Milpitas, CA 95035-2003 Milorganite 735 North Water Street Milwaukee, WI 53200 DowElanco Midland, MI 48674 Great American Outdoor 10100 Dennis Drive Urbandale, IA 50322 Monsanto Company Agricultural Products Division 800 North Lindbergh Boulevard St. Louis, MO 63167 Earthgro PO Box 143 Lebanon, CT 06249 Hallet Materials South Dayton Road Ames, IA 50010 D & K Turf Products 5191 NE 17th Street Des Moines, IA 50313 Dakota Peat PO Box 14088 Grand Forks, ND 58208 112 Ossian Inc. 635 S. Elmwood Avenue Davenport, LA 52808 PBI/Gordon Corporation 1217 West 12th Street PO Box 4090 Kansas City, MO 64101-9984 Pepsi-Cola General Bottlers, Inc. 3825 106th St. Des Moines, IA 50322 Pickseed West Incorporated PO Box 888 Tangent, OR 97389 Pursell 201 W. Fourth St. PO Box 450 Sylacauga, AL 35150 R.G.B. Laboratories Incorporated 1531 Charlotte Street Kansas City, MO 64108 Racing Association of Central Iowa 1 Prairie Meadows Drive PO Box 1000 Altoona, IA 50009-0901 Ringer Corporation Eden Prairie, MN 55344 Rohm and Haas Co. 7808 Highland Farms Road Houston, TX 77095 Sandoz AGRO, Inc. Raleigh, NC 27615 The Scotts Company 14111 Scottslawn Road Marysville, Ohio 43041 SportGrass, Inc. 6849 Old Dominion Drive, Suite 219 McLean, VA 22101 Spraying Systems Company N Avenue at Schmale Road Wheaton, IL 60187 Standard Golf Company PO Box 68 Cedar Falls, IA 50613 Sustane Corporation PO Box 19 Cannon Falls, MN 55009 Tri State Turf & Irrigation Co. 6125 Valley Drive Bettendorf, LA 52722 True Pitch, Inc. 803 8th Street SW Altoona, IA 50009 Turf-Seed, Inc. PO Box 250 Hubbard, OR 97032 United Horticultural Supply 14075 NE Arndt Road Aurora, OR 97002 Viridian Inc. (Formerly Sherritt Inc.) 3500 Manulife Place 10181 101st Street Edmonton, Alberta Canada TJ5 354 Weathermatic Corporation Telsco Industries PO Box 180205 Dallas, TX 75218-2005 TeeJet Spray Products 2400 NW 86th St. Urbandale, IA 50322 Williams Lawn Seed Company 224 South Hills Drive PO Box 112 Maryville, MO 64468 Terra Chemical Corporation Box 218 Quimby, IA 51049 Zeneca Professional Products 4300 Comhusker Hwy #B6 Lincoln, NE 68504 Rainbird Irrigation Company Reams Sprinkler Supply 13410 C Street Omaha, NE 68144 Rhone-Poulenc Chemical Company Black Horse Lane PO Box 125 Monmouth Junction, NJ 08852 The Toro Company Irrigation Division Riverside, CA 92500 113 ... and justice for all The Iowa Cooperative E xtension Service’s program s and policies are consistent w ith p ertin en t federal and state laws and regulations o n nondiscrim ination. M any m aterials can be m ade available in alternative form ats for ADA clients. Issued in furtherance of Cooperative E xtension w ork, Acts of May 8 and Ju n e 3 0 ,1 9 1 4 , in cooperation w ith the U.S. D epartm ent of Agriculture. N olan R. Hartwig, interim director, C ooperative E xtension Service, Iowa State University of Science and Technology, Ames, Iowa.