2003 Iowa Turfgrass Research Report University Extension Ames, Iowa Department of Horticulture Department of Plant Pathology Department of Entomology Cooperative Extension IOWA STATE UNIVERSITY FG-467/July 2003 In Cooperation with the Iowa Turfgrass Institute Io w a S t a t e U n iv e r s it y ' >\ ' WZy' ' ^ ■ ; ' *>.*: . ' ' Pond , ./'■ • -!?l V " . - fj- o " -"h ■ - ... :rn y’ .' *<* -■/êM h %; >■ , /J ! s¿:¿& , .. Á / * :i i ' / / . ”*«• . •:■. * ì- .1 < . ■<= ! , £ *, ’ ; " "■■., '. : ;: A B C D E F G H I J Preemergent Herbicide Trials Cool season grass variety trials; KBG, PR, TF Bentgrass Variety Trials Turfgrass Breeding Mowing Quality and Turf Performance Weed control and turf establishment with soil solarization The effect of simulated traffic on seedling turf species Superior Crabapple Selections for Iowa New Plant Cultivars for Iowa Landscapes and Gardens The Pest and Disease Detectives: A Systematic Approach to Diagnosing Landscaping Pest Problems - Luke Dant Nick Christians Nick Christians Shui-Zhang Fei Mark Howieson Federico Valverde Dave Minner James Römer Cindy Haynes Terry Finnerty and James Römer PESTICIDE CERTIFICATION TOPICS K Chuck Eckermann L Mark Hanna M Dr. Donald Lewis Pesticide Laws & Regulations Equipment calibration and safe application techniques Non-target injury and community problems iii Introduction Nick E. Christians, David D. Minner, and Shui-Zhang Fei The following research report is the 24th yearly publication o f the results o f turfgrass research projects performed at Iowa State University. This is the sixth year that the entire report is available on the Internet. This report and the previous years' reports can be accessed at: http://turfgrass.hort.iastate.edu/ In 2002-2003, a new genotype screening trial o f Roundup Ready® creeping bentgrass has been initiated. A trial on fairway and green conversion with Roundup Ready® creeping bentgrass has also been established at Veenker Memorial Golf Course to study the timing and frequency o f Roundup application to ensure a smooth transition with minimal disturbance. Morphological and genetic characterization o f a number o f turfgrass species including Poa trivialis, colonial and velvet bentgrass, and Kentucky bluegrass are being conducted to study the range and the pattern o f the variation and reproductive mode for breeding purposes. Another major project is the study o f winter hardiness of perennial ryegrass using both conventional and molecular marker tools with a long-term goal of breeding winter hardy perennial ryegrass. We experienced a dry fall in 2002 and this was followed by a cold but sunny winter with virtually no snow cover. These conditions were very conducive to winter injury by desiccation. Many o f the autumn seeded grasses, especially those that were established in the later part o f the fall, did not survive. Sod farms and other seedings that were exposed and open were damaged to the point that they required reestablishment in the spring o f 2003. Established turf on putting greens was also damaged during the winter. Both o f the creeping bentgrass and Poa annua greens were severely damaged by winter desiccation. A report with pictures is available at http://www.iowaturfgrass.org/wiletter.htm We would like to acknowledge Will Emley, superintendent of the ISU Horticulture Research Station; Rod St. John, manager o f the turf research area; Luke Dant, undergraduate Research Associate; Federico Valverde, research associate; Dr. Young Joo, visiting scientist; Deying Li, Postdoctoral researcher; Mark Howieson, Robert Wieners, Yanwen Xiong, S.K. Lee, and Jason Kruse, graduate students; and all others employed at the field research area in the past year for their efforts in building the turf program. Special thanks to Mark Hoffmann, and Sherry St. John for helping to prepare this publication. Edited by Nick Christians, David Minner and Shui-Zhang Fei, Iowa State University, Department o f Horticulture, Ames, IA 50011-1100. Dr. Nick Christians Phone: 515/294-0036 Fax: 515/294-0730 E-mail: nchris@iastate.edu Dr. David Minner Phone: 515/294-5726 Fax: 515/294-0730 E-mail: dminner@iastate.edu Dr. Shui-Zhang Fei Phone: 515/294-5119 Fax: 515/294-0730 E-mail: sfei@iastate.edu 2003 Iowa State Turfgrass Research Report Introduction...............................................................................................................................................................................iv Environmental Data 2002 Weather Data for the Turf Research Farm at Gilbert, IA.......................................................................................... 1 Species and Cultivar Trials 2000 High-Maintenance Kentucky Bluegrass Cultivar Trial.............................................................................................. 4 1999 Perennial Ryegrass Cultivar Trial................................................................................................................................. 7 2001 Tall Fescue Cultivar Trial............................................................................................................................................ 10 1998 Fine Fescue Cultivar Trial............................................................................................................................................ 13 1998 Fairway Height Bentgrass Cultivar Trial...................................................................................................................15 1998 Green Height Bentgrass Cultivar Trial.......................................................................................................................16 1999 Fairway Height Bluegrass Trial.................................................................................................................................... 17 Shade Adaptation Study..........................................................................................................................................................18 Ornamental Grasses Project 2000-2002................................................................................................................................ 19 Herbicide Studies Preemergence Crabgrass Control Trial 2002....................................................................... .............................................. 21 Postemergence Annual Grass Control Trial 2002...............................................................................................................23 Fairway Height Preemergence Herbicide Trial 2002..........................................................................................................25 The Effects of Preemergence Herbicides on Sod Tensile Strength 2002.......................................................................... 26 Postemergence Broadleaf Control Trial 1 2002....................................................................................................................27 Postemergence Broadleaf Control Trial H 2002..................................................................................................................29 Postemergence Broadleaf Control Trial HI 2002................................................................................................................ 31 Non-selective Herbicide Study 1 2002...................................................................................................................................34 Non-selective Herbicide Study H 2002.................................................................................................................................35 Broadleaf Herbicide Study 2002............................................................................................................................................ 36 Postemergence Annual Bluegrass Control Trial 2002....................................................................................................... 39 Genetics and Plant Physiology Research Analysis of Genetic and Morphological Variation of Colonial and Velvet Bentgrass.....................................................40 Analysis of Genetic Factors Associated with Winter Hardiness in Perennial Ryegrass..................................................41 Determination of Reproductive Mode of a USDA Core Collection of Kentucky Bluegrass...........................................42 Perennial Ryegrass Breeding Research 2001-2002..............................................................................................................44 Changes in Carbohydrate Metabolism in Response to Mowing....................................................................................... 45 Timing of Roundup® Application Critical when Converting Golf Course Greens and Fairways to Roundup® Ready Creeping Bentgrass..................................................................................................................................................................48 Plant Nutrition Research Cation Ratios and Soil Testing Methods for Sand-Based Golf Course Greens................................................................50 Development of Remote Sensing Techniques to Determine Moisture and Nutrition Stress...........................................51 Evaluation of Methylene urea Rate and Mixing Depth for Growth and Establishment of Poa pratensis L. on Sandbased Systems...........................................................................................................................................................................53 Turfgrass Disease Research Evaluation of Fungicides for Control of Dollar Spot and Brown Patch in Creeping Bentgrass................................... 56 Environmental Research 1991 Corn Gluten Meal Crabgrass Control Study - Year 12 - 2002................................................................................. 57 1995 Corn Gluten Meal Rate Weed Control Study - Year 8 - 2002.................................................................................. 59 1999 Corn Gluten Meal/Urea Crabgrass Control Study - Year 4 - 2002.......................................................................... 61 Soil Modification and Sand-Based Systems Research Wetting Agents and Hydrophobicity of Golf Course Fairways......................................................................................... 63 Introducing Iowa State University Personnel Affiliated with the Turfgrass Research Program........................................................66 Companies and Organizations That Made Donations or Supplied Products to the Iowa State University Turfgrass Research Program...................................................................................................................................................................67 V _H r_ © O © © O g in in F F F F "t co F F F co co co co co co CN CN CN _ _ _ F F F" F F F F F F m F n F •n F in m in m in F in F m F m F in F in F in in n vo t-* 00 Ov o * VO VO r-~ Ov F m Ov o fN ca ea ca ea ea ea ea $e3a ca ca ea ea ca ea ea ca ea (N Ov 00 O v OO O o Ov OO in 00 a tí tí f t tí tí t í tí tí tí tí tí tí tí tí tí m (N m F m CO vo F >n VO VO F F na na na na na na na na na na 2002 Weather Data for the Turf Research Farm at Gilbert, IA. 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Midnight (KGB) Ram I (KGB) Nassau (KGB) Coventry (KGB) Chateau (KGB) Sabre (Poa trivialis) Bristol (KGB) Glade (KGB) LSD o.os 7.0 6.3 7.0 6.7 6.3 6.3 5.3 6.0 5.7 6.0 6.0 6.0 6.0 6.0 5.3 5.0 4.7 4.3 4.3 4.7 4.3 4.0 5.0 4.3 3.3 3.7 2.7 1.3 1.7 2.3 2.0 1.7 1.3 1.7 1.7 1.66 7.3 6.7 7.0 7.0 6.3 6.7 6.3 6.7 6.3 6.7 6.3 6.3 6.0 6.3 5.0 4.7 5.7 4.7 5.0 5.3 5.0 4.7 4.7 3.3 3.7 2.7 2.7 2.0 2.3 1.7 2.0 1.7 2.7 2.0 1.3 1.87 6.3 6.7 6.0 6.0 6.7 6.0 7.0 6.0 6.0 6.0 5.7 6.0 6.0 5.3 5.3 5.3 5.0 4.7 5.0 5.0 5.3 4.7 4.3 4.0 4.0 4.0 3.3 3.0 2.7 2.0 2.0 2.3 2.3 1.7 1.3 1.43 6.7 7.0 6.3 6.7 6.7 6.3 6.3 6.0 6.3 5.7 6.3 5.7 6.0 5.0 6.3 5.0 5.0 5.3 5.3 5.0 5.0 3.7 4.0 4.7 4.3 4.0 3.7 3.0 2.7 4.0 2.7 2.0 1.7 2.0 2.0 1.80 7.0 6.7 6.7 6.0 6.3 6.3 6.7 6.3 6.0 6.3 6.3 6.3 6.3 6.0 5.7 6.0 5.3 6.0 5.0 5.3 5.3 5.0 4.3 4.7 4.7 5.3 4.7 3.0 2.7 2.3 2.3 3.0 2.0 2.3 2.0 1.54 7.7 7.7 7.0 7.3 7.0 7.3 7.3 6.7 7.3 6.7 6.7 7.0 6.7 6.3 7.3 6.0 6.0 6.0 6.0 5.3 5.3 5.7 4.7 5.0 5.0 5.0 4.7 3.3 2.7 2.3 2.0 2.3 2.0 2.0 3.3 1.90 Mean 7.0 6.9 6.7 6.6 6.6 6.5 6.5 6.3 6.3 6.2 6.2 6.2 6.2 5.8 5.8 5.3 5.3 5.2 5.1 5.1 5.0 4.6 4.5 4.3 4.2 4.1 3.6 2.6 2.5 2.4 2.2 2.2 2.0 2.0 1.9 1C.F. = chewings fescue, C.R.F. = creeping red fescue, H.F. = hard fescue, KGB = Kentucky blue grass, T.F. = tall fescue. 18 Ornamental Grasses Project 2000-2002 N ick C hristians Purpose: The purpose of the ornamental grass project is to evaluate 34 ornamental grasses for their adaptation to Iowa conditions. The study is located south of the turfgrass research building. Grasses 1 and 2 were established in 1989. Grasses 3-5, 11-15, 17-18, 20-21, and 33 were established in 2000. The remaining grasses were established in June of 2001. Each plot on this site has a 4 x 5 ft spacing. The grasses descend in height from number one in the center, to 34 on each of the ends. The 34 grasses are replicated twice on the two sides of the arc. Choosing the species: Ornamental grasses have numerous characteristics, each that could make a difference in which species is chosen for a particular landscape. For the plots at the Horticulture Research Station, the new species have general characteristics of being bunch type, non-aggressive, varying in color, form and shape, in addition to being able to grow in the zones 4 and/or 5. The grasses will remain in this location for several years. They will be evaluated on their winter survival and overall adaptation to local conditions. 1 VO OO Óo ^ »O" in i i V © tji- oo Tti vo m ïn ■r- vo C/5 C/3 CC c/5 'i' *H S-H Hi H .2 1/3 co 2 8 -S-S o o Ch o Q> O o Hh CS CS .S .s 00 CD -C T3 J H H CD < H « CO „ 3 -I &> I a g -á l s £ :s £ > jo g S ^ en en ; ” s s w I -b •§ -S a a g s s 2 -3 -P —ä ) ^ ’S I I hOOO\ OH 20 _ h T5 *—h CS (N M fN i Tl gI f N m ^ i n o h ú o o v O ' - ' M m ^ t i n o h x o v o ^ f S m ' í HF-HHH^Hr-Hr-H^H(s| o U co co ei U bl) X ei b U m m n O n 'O n, »O (N 00 m -H t-H ^ un (N (N (N N© 0s g s *E X) n i - m oc * NO X Pu Ci O'* ON ^ ^ 0\ vo C O 00 £ CO S ÿU (N O O (N O S H CJ O'* On on on O'n 1 < o o o £ 7 o o o a H O» 03 £ $fl O ■2 d 5 o bH £O „ N N N _ (N (N CO o C/5 co a bb •«H s O tí bß ö '+-* co O Ph ON 't Tt oo (N h ^ o h h ^ O O O o O U, (D a < ^ ^ ei •c d S fl in o » ^ ta T5 W N W Q » d » u fl X! d H a a 13 » if l __Ë h JS ’S « "w w (N en Tt un 24 o o O 03 J Fairway Height Preemergence Herbicide Trial 2002 Nick Christians and Luke Dant The 2002 fairway height preemergence trial was conducted at the Iowa State University Turfgrass Research Facility on an area of ‘Quantum Leap’ Kentucky bluegrass maintained as a golf course fairway at 0.5 in. mowing height. The area for the trial was limited and the study was conducted with two replications instead of the standard three replications. The herbicides were applied on May 14 with a C 02 backpack sprayer with #8002 flat fan TeeJet nozzles at 30-40 psi and diluted to a total spray volume of 3 gal per 1000 sq. ft. The second application of treatment 1 was made on July 1 using die same procedure as described above. The soil on the area is a Nicollett (fine-loamy, mixed, mesic Aquic Hapludoll) with 3.3 % organic matter, 7 ppm P, 50 ppm K, and a pH of 6.65. Data were analyzed using Statistical Analysis System (SAS) software and the Analysis of Variance procedure. Treatment effects were tested using Least Significant Difference (LSD) test. Crabgrass populations were variable on the site. Treatment 1 (low rate of Dimension Ultra) had higher crabgrass populations than that of the control plots. This is most likely due to great variability of crabgrass populations at the site. However, it was clear that the 0.25 lb ai/A rate of Dimension was not sufficient to control crabgrass on this site, whereas the 0.5 rate was effective. The Barricade at 0.5 lbs ai/A was also effective in this test. No damage from the treatments was observed on the Quantum Leap bluegrass at anytime during the study. Table 1. Fairway height bluegrass preemergence trial 2002. Material Rate lb a.i./A % Crabgrass Cover 7/23 8/19 9/23 1 Dimension Ultra 40 WP2 (Split Applications) 0.25 6 28 20 2 Dimension Ultra 40 WP2 0.5 1 1 0 3 Barricade 65 WG2 0.5 0 1 1 4 Untreated Control NA 6 14 11 NS 17 NS LSD 0.05 25 The Effects of Preemergence Herbicides on Sod Tensile Strength 2002 Nick E. Christians and Luke Dant The objective of this study was to evaluate sod tensile strength and quality of turf treated with preemergence herbicides. The study was conducted at the Iowa State University Turf Research Facility on ‘Glade’ Kentucky bluegrass. Treatments included Barricade (Prodiamine) 4FL at 0.5, 0.75, and 1 lb a.i./acre and Barricade 65 WG at 1.0 lb a.i./acre. The study was conducted as a randomized complete block. Each treatment was replicated four times with plots being 5 ft by 15 ft. All treatments were applied on April 26 using a carbon dioxide backpack sprayer with #8002 flat fan Tee Jet nozzles at 30-40 psi and diluted to a total spray volume of 3 gal per 1000 sq. ft. The soil on the area is a Nicollett (fine-loamy, mixed, mesic Aquic Hapludoll) with 4.0 % organic matter, 11 ppm P, 90 ppm K, and a pH of 6.75. Sod harvest dates were approximately 30, 60, 90 and 120 days after application of the herbicides. Sod was harvested from a subsection of each plot using an 18” sod cutter set at a cutting depth of 1/2-inch. The sod was then placed in a clamp that was attached to a hydraulic jack. A gauge placed in the hydraulic system recorded the pressure in pounds per square inch (psi) needed to break each piece of sod. Sod harvested from each plot was broken 4 times. One outlying data point was dropped and the remaining three were averaged. The mean of the three numbers were recorded as a single data point for that date and treatment. An analysis of variance was performed on the data using SAS (Statistical Analysis System). The herbicide treatments had no effect on turf quality at any time during the study. There were no significant differences in sod tensile strength on any of the four testing dates (Table 1). Table 1. Sod tensile strength study 2002. Data are lbs/in2 required to break 18 inch sod pieces. Material 1 2 3 4 5 Untreated Control Barricade 4 FL Barricade 4 FL Barricade 4 FL Barricade 65 WG Rate lb a.i./A Sod Tensile Strength psi NA 0.5 0.75 1.0 1.0 LSD 0.05 26 5/28 6/26 7/25 8/31 430 408 413 348 404 400 411 433 416 464 330 318 300 306 284 279 234 216 216 214 NS NS NS NS Postemergence Broadleaf Control Trial I 2002 Nick E. Christians and Luke Dant The purpose of this study was to evaluate weed control and turf phytotoxicity of Scotts Weed-B-Gone and other competitive broadleaf herbicide formulations. The research was conducted at the Iowa State University Turfgrass Research Facility on ‘Parade’ Kentucky bluegrass. The trial was arranged as a randomized complete block. Each treatment was replicated three times with plots being 5 ft x 5 ft. All products were supplied by Scotts Company. Non-Scotts products were applied at label rates. All treatments were applied using a carbon dioxide backpack sprayer with #8002 flat fan nozzles at 30-40 psi and diluted to a total spray volume of 3 gal per 1000 sq. ft. The herbicide application was made on May 14, 2002. The soil on the area is a Nicollett (fine-loamy, mixed, mesic Aquic Hapludoll) with 4.9 % organic matter, 6 ppm P, 171 ppm K, and a pH of 7.05. Ratings of damage to dandelions were made at 1 and 3 days after application and at 1 and 3 weeks after application with a percentage scale ranging from 0 to 100. On June 4, five weeks after application, a percentage of dandelion coverage was taken. Turfgrass phytotoxicity was monitored at one and three weeks after application on a scale ranging from 9-1, with 9 being no damage and 1 being complete turf death. Data were analyzed using Statistical Analysis System (SAS) and the Analysis of Variance procedure. Treatment effects were tested using Least Significant Difference (LSD) test. No damage was observed on the Kentucky bluegrass turf at any time during the study (Table 1). Ail materials caused significant damage to weeds at 1 day after treatment. By the second day, the Trimec + Sulfentrazone was showing the most damage on weeds, followed by the Spectracide Weed Stop. All materials provided significant reduction in dandelion cover compared to the control. However, none of the treatments provided 100% control. There were no significant differences among the herbicide treatments in dandelion control, although WBG S-10304 provided the greatest numerical reduction. 27 28 Postemergence Broadleaf Control Trial II 2002 NickE. Christians and Luke Dant The purpose of this study was to evaluate weed control and turf phytotoxicity of Scotts Turf Builder with Plus 2 Weed Control to other competitive granular broadleaf herbicides. The research was conducted at the Iowa State University Turfgrass Research Facility on ‘Park’ Kentucky bluegrass. The trial design was a randomized complete block. The plots were 10 ft x 5 ft and each treatment was replicated 3 times. The Scotts Company provided all products and each product was applied per the instructions on the label. The application was made when dandelions were flowering but before they had produced “puff-balls”. All treatments were applied on May 14 while there was still dew on the weed foliage. All products were applied using ‘shaker dispensers’. The soil on the area is a Nicollett (fineloamy, mixed, mesic Aquic Hapludoll) with 4.6 % organic matter, 6 ppm P, 169 ppm K, and a pH of 7.05. Weed phytotoxicity was reported two weeks after application on June 28. This was reported on a percent scale, 0% being no damage and 100% being dead. Dandelion and clover cover was recorded 4 and 8 weeks after application on June 11 and July 9. These data were reported on a percentage basis with 0% meaning there were no weeds present and 100% meaning the entire plot was covered by weeds. Turf Quality was taken 2,4 and 8 weeks after application on a scale of 9-1 (9 = Excellent, 6 = Acceptable, 1 = Worst). Data were analyzed using Statistical Analysis System and the Analysis of Variance procedure. Treatments effects were tested using the Least Significant Difference (LSD) test. Weeds treated by all materials showed some damage two weeks after the application. However, none of the damage was statistically significant between the treatments. All of the herbicides used in the study reduced dandelion populations in comparison with the control. No particular product appeared to have greater activity on dandelions than any other product. As with dandelions, all the treatments reduced clover populations significantly. Preen’n Green Lawns provided the best clover control on June 11,4 weeks after application By July 9, both Preen’n Green Lawns and S-10218 exhibited the best numerical control of clover but there were no statistically significant differences among herbicide treatments. There was not a large differences in turf quality among the treated plots at any time during the study. Table 1. 2002 Postemergence broadleaf control trial II treatments. Total Active Ingredients Material Active Ingredients 1 Untreated control NA NA 2 Scotts Turf Builder with Plus 2 Weed Control S-10219 1.81% 2,4-D (1.21%) MCPP-p (0.6%) 3 S-10218 1.89% 2,4-D (1.21%) MCPP-p (0.6%) Dicamba (0.08%) 4 Vigoro Weed & Feed 0.85% 2,4-D (1.21%) MCPP (0.27%) Dicamba (0.03%) 5 Sta-green 200 + Weed & Feed 0.98% 2,4-D (0.64%) MCPP (0.31%) Dicamba (0.03%) 6 Sam’s Choice Weed & Feed 1.14% 2.4D (0.56%) MCPP (0.29%) 2.4DP (0.29%) 7 Preen’n Green Lawns 1.93% Benefin (0.82%) Trifluralin (0.43%) Triclopyr (0.5%) Clopyralid (0.18%) 8 Lesco Weed & Feed 1.14% 2.4-D (0.56%) MCPP (0.29%) 2.4DP (0.29%) 29 On O «O VO NO NO Tt N O V N N O r ^ t ^ N O 'O rf NO NO no fH no NO NO NO O) Z g fl0 a «U W 0 H N© 00 rj Í5 h(U , NO NO NO NO «O Tj1 no ^ oo ^ ^ (N ON #0o O 3 0 g PS â *n (N © © O ï/5 P oo „ 2S Ä0 W © Hi P C» *H C/5 (S en V) 30 Postemergence Broadleaf Control Trial III 2002 Nick E. Christians and Luke Dant The purpose of this study was to evaluate the effectiveness of several broadleaf herbicides, specifically for control of wild violet, but also for control of other broadleaf weeds that may be present in the plot. The study was conducted at the Iowa State University arboretum. The experimental design was a split plot design with main plots being the control and 10 herbicide treatments as the sub-plots. Some treatments were applied as a single application of the materials (App 1) and other treatments had repeat applications made 21 days following the first application (App 2). The main plots were 10 ft x 5 ft and were split in half into 2 sub-plots measuring 5 ft x 5ft. Each treatment was replicated three times. All of the main plot treatments were applied on May 9 using a carbon dioxide backpack sprayer with #8002 flat fan TeeJet nozzles at 30-40 psi and diluted to a total spray volume of 3 gal 1000 sq. ft.. The first application was made to the entire 10 ft x 5 ft plot. The second application was made on May 30, 21 days after the first application, however, only one half of the plot was sprayed. Treatment numbers 2 and 3 only required one application; therefore, they were not sprayed a second time. The sub-plots were randomly assigned within the main plots. Both wild violet and ground ivy damage was reported 2, 7, 14, 21 and 28 days after the first application and again 5 and 7 days after the second application (Tables 1-4). This was reported on a percent scale of 0% being no damage and 100% being dead. The percent wild violet and ground ivy cover was estimated 14,21,28 and 35 days after the second application based on a percent scale (0% = No weeds and 100% being complete covered by weeds). On the 2nd day after application (5/11), there were only minor differences in weed damage on wild violets among the treatments (Table 1). The EH1349 had the least effect on weeds at that time. By 7 days after treatment (5/16), Speed Zone and Power Zone showed a clear advantage over the other treatments in weed damage. This is likely due to the presence of carfentrazone in these product, which is added to speed their activity on weeds. The effect of the second application can be seen on 6/6, when several of the treatments showed a distinct advantage over the single application alone. Power Zone at 6 pt/A and Millennium Ultra were showing the greatest effect on that date. The herbicides that provided the best overall control of wild violets on 7/3 were Speed Zone at 4.5 pt/A, Confront at 1 pt/A, and EH1349 at 4 pt/A. All materials tested significantly reduced wild violet numbers from the control. Weed damage on ground ivy was much better with Speed Zone and Power Zone at days 7 and 14 following application. As was the case with wild violet, repeat applications showed a distinct advantage for most treatments on 6/6. All treatments significantly reduced ground ivy cover at all observation dates during the study (Table 4). There was not as great of a difference between 1 and 2 applications on the ground ivy control as was observed on the wild violet control. Table 1. Initial damage to wild violets following herbicide application. (0 = no damage and 100=dead) Weed Phytotoxicity Material 1 2 3 4 5 6 7 8 9 10 11 Untreated Control Speed Zone* Power Zonet Speed Zone Speed Zone Power Zone Millennium Ultra Confront Trimec Classic EH1349 NB30165 LSD Rate Product (pt)/A NA 5.0 6.0 4.5 5.0 5.0 2.5 1.0 4.0 4.0 4.0* Initial Cover 38 14 13 18 34 24 23 22 8 6 34 5/11 5/16 5/23 6/4 App 1 App 1 App 1 App 2 App 1 App 2 0 10 15 15 10 15 15 10 10 5 15 0 20 32 33 30 23 7 5 8 5 5 0 32 27 40 33 17 5 5 5 8 5 0 13 20 33 37 27 37 12 30 15 18 0 10 18 7 7 5 5 5 5 10 5 0 10 40 10 25 20 40 5 30 27 30 1 1 1 10 4 4 * Single application * 4.0 qt/A 31 6/6 Table 2. Wild Violet control by postemergence herbicides. % Weed Cover Material 1 2 3 4 5 6 7 8 9 10 11 6/13 6/27 6/20 7/3 A ppi App 2 Appi App2 A ppi App 2 A ppi App 2 Untreated Control Speed Zone* Power Zone* Speed Zone Speed Zone Power Zone Millennium Ultra Confront Trimec Classic EH1349 NB30165 33 17 28 37 36 37 35 26 8 17 34 27 9 18 6 14 5 16 28 19 5 10 22 18 16 14 25 23 22 10 5 11 21 22 18 19 3 10 9 9 7 10 9 15 27 5 17 23 17 25 15 14 3 7 20 27 13 14 3 20 12 7 6 6 4 16 36 17 15 14 18 26 18 13 4 7 21 36 9 12 4 15 12 9 5 8 4 15 LSD 17 17 11 11 10 10 11 11 * Single application Table 3. Initial damage to ground ivy following herbicide application. Weed Phytotoxicity M aterial 1 2 3 4 5 6 7 8 9 10 11 Untreated Control Speed Zone* Power Zone* Speed Zone Speed Zone Power Zone Millennium Ultra Confront Trimec Classic EH1349 NB30165 LSD Rate Product (pt)/A NA 5.0 6.0 4.5 5.0 • 5.0 2.5 1.0 4.0 4.0 4.0* 5/16 5/23 6/4 A ppi App 1 App 2 A ppi App 2 0 28 35 22 27 25 3 2 3 8 10 0 27 47 25 28 32 5 3 5 8 8 0 5 5 45 50 45 43 10 28 12 23 0 10 18 7 7 5 5 5 5 10 5 0 10 40 10 25 20 40 5 30 27 30 1 1 13 3 3 t Single application * 4.0 qt/A 32 6/6 Table 4. Ground ivy control by postemergence herbicides. % Weed Cover Material 1 2 3 4 5 6 7 8 9 10 11 6/20 6/13 6/27 7/03 Appi App 2 Appi App2 Appi App 2 Appi App 2 Untreated Control Speed Zone* Power Zone* Speed Zone Speed Zone Power Zone Millennium Ultra Confront Trimec Classic EH1349 NB30165 47 3 3 6 7 4 6 7 3 7 6 47 3 3 1 3 3 2 6 2 2 2 47 6 4 4 9 3 9 8 2 6 4 47 5 4 1 2 2 1 6 2 3 2 32 4 3 2 9 3 4 3 1 2 3 32 2 3 1 2 1 1 1 1 1 2 20 1 4 3 11 2 4 2 1 2 3 23 1 4 0 2 2 0 1 1 1 2 LSD 3 3 3 3 4 4 3 3 * Single application 33 Non-selective Herbicide Study I 2002 Nick E. Christians and Luke Dant This study was conducted to evaluate the efficacy and speed of kill of several non-selective herbicides. This study was conducted at the Iowa State University Turfgrass Research Facility on ‘Ram I’ Kentucky bluegrass. The soil on the area is a Nicollett (fine-loamy, mixed, mesic Aquic Hapludoll) with 4.1 % organic matter, 11 ppm P, 96 ppm K, and a pH of 6.75. All treatments were replicated three times and the experimental design was a randomized complete block. Individual plots were 5 ft by 5 ft in size. Each treatment was diluted to a total spray volume of 3 gal per 1000 sq ft and applied using a carbon dioxide backpack sprayer with #8002 flat fan TeeJet nozzles at 30-40 psi. All treatments were applied on July 17. Turfgrass phytotoxicity was observed on 1, 2, 5, 7, 14,21, 28 and 45 days after application. Phytotoxicity was reported on a scale ranging from 9-1, with 9 being no damage and 1 being complete death of the turf. Data were analyzed using Statistical Analysis System (SAS) and the Analysis of Variance procedure. Treatment effects were tested using Least Significant Difference (LSD) test. Grass treated with Reward 2 SL was the only turf that showed significant damage on the first and second day after treatment (Table 1). By day 5, all treated turf was showing significant damage, with Reward 2 SL still showing the greatest effect. By the 7th day, Roundup RTU and A 13693 applied at the high rate had equaled the effect of the Reward 2 SL. Although Reward 2 SL had quick activity, by 8/7, 21 days after application, the turf had almost completely recovered. On 8/31, 45 days after treatment, Touchdown RTU and A 13693 applied at the high rate had completely killed all of the turf. Table 1. Comparison of the time required to kill Kentucky bluegrass among several non-selective herbicides. (9=no damage and l=dead turf) Material 1 Untreated control Turfgrass Phytotoxcity Rate qt/A 7/18 7/19 7/22 7/24 NA 9 9 9 9 9 7/31 8/7 8/14 8/31 9 9 9 3 4 2 2 1 2 2 Touchdown RTU YF11614 36 9 9 7 7 4 3 Touchdown 13.4% (152 AE) 2 9 9 8 7 4 4 Roundup RTU (AE) 48.2 9 9 7 6 4 3 3 3 9 7 5 4 3 2 7 17.8 9 9 8 6 8 9 9 7 5 Roundup Cone. 18% A1 (13.4% AE) 1.41 9 6 Reward 2 SL 0.5 7 7 A13693 6 7 8 8 9 4 3 3 3 2 1 7 4 3 6 6 4 5 4 4 3 2 8 A13693 35.6 9 A13692 0.98 9 9 2 9 9 8 8 6 8 6 9 9 8 8 6 6 5 5 9 9 8 8 5 5 3 3 0.5 0.3 0.6 1.1 0.9 0.9 0.9 1.5 10 11 12 A13692 Roundup Cone. 18%A1 (13.4% AE) & Reward 2 SL Roundup Cone. 18% A1 (13.4% AE) & Reward 2 SL LSD 0.05 0.7 0.032 0.032 0.066 34 Non-selective Herbicide Study II 2002 Nick E. Christians and Luke Dant The purpose of this study was to compare the speed of activity and length of control of Monsanto’s QuikPRO and Roundup ProDry. This study was conducted at the Iowa State University Turfgrass Research Facility on ‘Ram I’ Kentucky bluegrass. The soil on the area is a Nicollett (fine-loamy, mixed, mesic Aquic Hapludoll) with 4.1% organic matter, 11 ppm P, 96 ppm K, and a pH of 6.75. The trial design was a randomized complete block. The plots were 5 ft x 5 ft and each treatment was replicated three times. Each treatment was diluted to a total spray volume of 3 gal per 1000 sq ft and applied using a carbon dioxide backpack sprayer with #8002 flat fan TeeJet nozzles at 30-40 psi. All treatments were applied on July 17. Turfgrass phytotoxicity was monitored at approximately 1, 2, 3, 7, 28, 56, and 84 days after application on a scale ranging from 9-1, with 9 being no damage and 1 being complete death of the turf. Data were analyzed using Statistical Analysis System (SAS) and the Analysis of Variance procedure. Treatment effects were tested using Least Significant Difference (LSD) test. The QuikPRO treated plots were showing significant damage on the first day after treatment (Table 1). The Roundup ProDry treated plots did not show damage until the 5th day after treatment. QuikPRO had completely killed the grass by day 7, whereas, it was 14 days following treatment before Roundup ProDry completely killed the turf. None of the treated grass showed any sign of recovery at the end of the season. Table 1. Comparison of the time required to kill Kentucky bluegrass of QuikPro and Roundup ProDry. (9=no damage and l=dead turf) Material Turfgrass Phtyo toxicity J*" * ________________________________________________ 7/18 7/19 7/20 7/22 7/24 7/31 8/7 8/14 8/28 9/13 10/14 1 Untreated Control NA 9 9 9 9 9 8 8 9 9 9 9 2 QuikPro (66.6% glyphosate) Roundup ProDry (64.9% glyphosate) 6 6 4 4 2 1 1 1 1 1 1 1 6 9 9 9 7 4 1 1 1 1 1 1 0.8 0.8 0.8 0.8 1.2 0.8 0.8 1.0 1.0 1.0 1.0 3 LSD 0.05 35 Broadleaf Herbicide Study 2002 D.D. M im er, F. Vaiverde, and S.K. Lee Introduction Broadleaf weeds such as white clover (Trifolium repens) and dandelion (Taraxicum officinale) are a problem on many turf sites. These problem weeds are seldom controlled with a single application of currently available broadleaf herbicides. The purpose of this study was to evaluate the efficacy of several post-emergency broadleaf weed control herbicides applied in a single application. Materials And Methods This study was conducted in Ames, Iowa at the Iowa State University Horticulture Research Station from July 10 to August 29, 2002. Following the recommendations on the suitable area for the study, the trial was set on a mature stand of Kentucky bluegrass (P o a p ra ten sis) infested with a uniform population of white clover and a very low population of Dandelion. The turf was routinely irrigated and mowed at 2.5 inches. Urea-nitrogen was applied at 1.0 lb N/1000 sq.ft, two weeks prior to herbicide treatment. Treatments were arranged in a Randomized Complete Block design with 3 replications and 14 treatments (Table 1). Each replication had 14 individual 6 x 4-ft plots including a non-treated control. Treatments were applied using a C02 backpack sprayer on July 16, 2002. The delivery rate of the sprayer was 125 gallons/A. Control plots only received a water spray. Table 1. Treatment description and rate of application. 1-RTV 01-02 2-RTV 02-02 3-RTV 03-02 4-RTV 04-02 1.6 oz./M 1.3 oz./M 1.1 oz./M(not applied) 1.1 oz./M 8-RIV 10-02 1.1 oz./M 9-RTV 11-02 1.1 oz./M . . 10-RTV 12-02 1 1 oz./M 6-RTV 06-02 .9 oz./M 11-RTV 13-02 1 1 oz./M 12-RTV 20-02 .9 oz./M 13-RTV 21-02 1 1 oz./M 7-RJV 07-02 1.1 oz./M 14-Control 5-RIV 05-02 .9 oz./M . Treatment three was listed on protocol, but was not received in shipment. However, it was treated (just water) and evaluated as any other treatment. Data collection involved a visual estimation of the percent of the plot area covered by white clover at 9 and 29 days after treatment (DAT). When rating at 9 DAT some plants of white clover did not die completely; therefore weed color was used to further evaluate herbicidal activity on a scale of 1 to 9, where 9 is a healthy green weed and 1 was a necrotic brown weed. Turf phytotoxicity was visually assessed on a color scale; data for this variable were collected prior to treatment and at 29 DAT. A similar scale was used for this purpose, where 9 is a healthy green grass plant and 1 is completely brown. Even though no initial data was collected on dandelions due to its scarce presence, the population of this weed increased abruptly in several plots after treatment. A visual estimation of the percent ground coverage of this species was done at 44 DAT. Data were analyzed with Statistical Analysis System (SAS, Version 8.0) and Analysis of Variance procedure (ANOVA). Treatment effects were tested using Fisher’s Least Significant Difference (LSD) mean separation test. Results The study area had a uniform stand of white clover as evident from non-significant differences between plots prior to treatment. Statistically significant differences in coverage and color of white clover occurred on July 25 and August 14, 2002, respectively (Table 2). Table 2. Analysis of variance for turf broadleaf herbicide study. Before treatment (July 10) Coverage of NS White Clover Color of n/a White Clover ** Significant at the a = 0.01 probability level, NS = not significant. 36 9 DAT (July 25) ** 29 DAT (August 14) ** Compared to the control, all broadleaf herbicides significantly reduced the amount of white clover (Table 3). There were few differences among herbicides and rates with the exception of RTV03-02 (as expected), which resulted in less control of white clover. Treatments RIV4-02, RIV7-02 and RIV20-02 showed the minimum coverage of white clover by the end of the study. However, those that showed a greater reduction (based on initial and final population) were RIV04-02 and RIV07-02. Table 3. Percentage of White Clover ( Trifolium repen s ) coverage on 2 different dates after herbicide application. Coverage of White Clover (%) Change of % cover Before Treatments 29 DAT 9 DAT treatment Julyl6-July25 Julyl6-Aug.l4 (August 14) (July 25) (July 10) 23.330 10.67cd 16.667b -12.67 -6.67b RIV 01-02 1.6 oz./M 33.330 16.00cd 20.00b -17.33 -13.33b RIV 02-02 1.3 oz./M 23.330 26.67b 73.33a RIV 03-02 1.1 oz./M* 50.00a 3.33 36.670 10.67cd 11.67b -26.00 -25.00b RIV 04-02 1.1 oz./M 40.000 12.33cd 18.33b -21.67b RIV 05-02 0.9 oz./M -27.67 30.000 10.67cd -16.67b 13.33b -19.33 RIV 06-02 0.9 oz./M 40.000 RIV 07-02 1.1 OZ./M 15.67cd 11.67b -24.33 -28.33b 18.33bc 20.00b RIV 10-02 1.1 OZ./M 36.670 -18.33 -18.67b 26.670 8.67d 20.00b -18.00 -6.67b RIV 11-02 1.1 oz./M 30.000 11.33cd 16.67b -18.67 -13.33b RIV 12-02 1.1 oz./M 33.330 13.33cd 16.67b -16.67b RIV 13-02 1.1 OZ./M -20.00 26.670 11.67cd 11.67b -15.00 -15.00b RIV 20-02 0.9 oz./M 30.000 14.33cd 15.00b -15.67 -15.00b RIV 21-02 1.1 oz./M 26.670 36.67a 86.67a 10.00 60.00a Control ** 22.66 NS 8.45 ** 14.88 ** NS LSD(a = 0.05) ** Significant at the a = 0.01 probability level, NS = not significant. z Treatment not applied When evaluating the weed plants that survived treatments (Table 4), it is observed that RIV13-02 caused greater damage to white clover although not statistically different than 4 other treatments. Table 4. Color of White Clover (Trifolium repen s) on 2 different dates after herbicide application. 9 DAT 29 DAT Treatment (July 25) (August 14) 7.33b RIV 01-02 1.6 oz./M 7.67a 7.00bc RIV 02-02 13 oz./M 7.67a 9.00a 7.67a RIV 03-02 1.1 oz./M* RIV 04-02 1.1 oz./M 5.67cde 6.67bc 5.00de 6.33cd RIV 05-02 0.9 OZ./M RIV 06-02 0.9 oz./M 5.00de 6.33cd 6.00bcde RIV 07-02 1.1 oz./M 6.67bc 7.33b 7.00abc RIV 10-02 1.1 oz./M RIV 11-02 1.1 oz./M 6.33bcd 7.00abc 7.00bc 7.00abc RIV 12-02 1.1 oz./M 4.67 e 5.67d RIV 13-02 1.1 oz./M 7.00bc 7.33ab RIV 20-02 0.9 oz./M RIV 21-02 1.1 oz./M 6.33bcd 6.67bc 9.00a 7.67a Control 149 ** 0.88 ** LSD(a = 0.05) ** Significant at the a = 0.01 probability level, NS = not significant. z Treatment not applied None of the herbicide treatments resulted in visible phytotoxicity that caused turfgrass browning or necrosis; however, there were slight differences in turf color (Table 5). Although the differences were slight, RIV20-02 had a significantly lower turf color than the control. The Kentucky bluegrass turf remained actively growing during the entire study with no evidence of grass injury by treatments or environmental conditions. 37 Table 5. Color of Kentucky bluegrass (P oa p ra te n sis ) on 2 different dates. Before treatment (July 10) RIV 01-02 1.6 oz./M 6.67 RIV 02-02 1.3 oz./M 6.00 7.00 RIV 03-02 1.1 0Z./M2 6.33 RIV 04-02 1.1 oz./M 6.67 RTV 05-02 0.9 oz./M RIV 06-02 0.9 oz./M 6.33 RIV 07-02 1.1 oz./M 6.67 6.33 RIV 10-02 1.1 oz./M 6.33 RIV 11-02 1.1 oz./M 6.00 RIV 12-02 1.1 oz./M RIV 13-02 1.1 oz./M 6.00 RIV 20-02 0.9 oz./M 6.33 6.00 RTV 21-02 1.1 oz./M 6.33 Control LSD(q = 0.05) ________1.44 NS NS = not significant. 2 Treatment not applied 29 DAT (August 14) 8.00a 8.00a 8.00a 8.00a 7.67ab 7.67ab 8.00a 8.00a 7.67ab 8.00a 7.67ab 7.33b 8.00a 8.00a 0.5879 The dandelion population was not prevalent in the study area during treatment; however, treatment differences were noticeable after completion of the study. Therefore, a final rating of dandelion was conducted 44 DAT. Table 6. Percent ground coverage of Dandelion observed 44 DAT. Percent coverage Treatment 44 DAT________ 5.67d RIV 01-02 1.6 oz./M RIV 02-02 1.3 oz./M 13.33bcd 22.67ab RIV 03-02 1.1 0Z./M2 7.33d RIV 04-02 1.1 oz./M 7.33d RIV 05-02 0.9 oz./M 14.00bcd RIV 06-02 0.9 oz./M 14.00bcd RIV 07-02 1.1 oz./M 20.67abc RIV 10-02 1.1 oz./M 5.00d RIV 11-02 1.1 oz./M 13.33bcd RIV 12-02 1.1 oz./M 21.33abc RIV 13-02 1.1 oz./M 9.67cd RIV 20-02 0.9 oz./M 10.67bcd RIV 21-02 1.1 oz./M 29.33a Control LSD(a = 0.05)___________ 12.07 2 Treatment not applied 38 Postemergence Annual Bluegrass Control Trial 2002 Nick Christians and Luke Dant The purpose of this study is to evaluate the effectiveness of varying rates of Velocity (bispyrobac-sodium) herbicide. The study is being conducted at Veenker Memorial Golf Course on ‘Cato’creeping bentgrass maintained at fairway height. All plots in the trial were 5 ft by 5 ft and organized in a randomized complete block design. The initial treatments of Velocity herbicide were made on August 1, 2002. They were applied using a carbon dioxide backpack sprayer with #8002 flat fan TeeJet nozzles at 30-40 psi and diluted to a total spray volume of 3 gal per 1000 sq. ft. For the treatments of Velocity herbicide requiring split applications, the second treatment was made on August 14. Prograss was applied per label instructions at a rate of 0.75 lb per acre. Prograss was applied on October 8 and again on October 30. The phytotoxic effects of Velocity were recorded two weeks after each herbicide application. A scale from 1 to 9 with 1 being complete turfgrass death and 9 being no damage was used. Beginning September 5, turfgrass quality was observed to track the recovery of damaged turf. Turfgrass quality was rated on a scale of 9-1 with 9 being excellent, 6 being acceptable and , 1 being the worst. On May 20,2003 when P o a annua was most visible, the percentage of P o a annua covering each plot was recorded. Data were analyzed using Statistical Analysis System and the Analysis of Variance procedure. Treatments effects were tested using Fisher’s Significant Difference (LSD) test. Table 1. Rate Trt Material Turfgrass Phyto toxicity Turf Quality % Poa Annua Coverage 8/6/02 8/14/02 8/22/02 8/29/02 9/5/02 9/20/02 10/4/02 10/25/02 5/20/03 Rate g a.i./A lb a/i. A N/A N/A 9 9 8 9 9 9 9 9 23 30 0.066 6 8 7 7 9 9 9 9 20 30 0.066 6 7 8 7 8 8 9 9 15 45 0.099 6 7 9 9 9 9 9 9 17 45 0.099 6 6 6 5 5 6 7 9 17 60 0.132 6 6 8 8 9 9 9 9 15 60 0.132 6 6 4 3 4 5 7 8 20 8 Velocity 80WP 90 0.198 6 4 8 9 9 9 17 N/A 0.75 9 9 9 8 8 8 9 Prograss 1.5EC 9 9 9 9 1 0 1.2 2.0 2.5 0.83 0.57 0.63 NS 9.25 1 Untreated Control 2 Velocity 80WP 3 Velocity 80WP (Split Application) 4 Velocity 80WP 5 Velocity 80WP (Split Application) 6 Velocity 80WP 7 Velocity 80WP (Split Application) LSD 39 Analysis of Genetic and Morphological Variation of Colonial and Velvet Bentgrass Shui-ZhangFei Shanmugam Rajasekar, Colonial bentgrass is a cool-season, sod-forming perennial primarily grown in northeastern and northwestern regions of the United States. This fine textured grass spreads by short rhizomes and stolons to form close tight turf. Colonial bentgrass is better adapted to mowing height of 0.5 inch and is best suited to golf course fairways and tees rather than greens. It requires low maintenance and low fertility, and it is also more cold tolerant than Kentucky bluegrass. Velvet bentgrass, the finest textured of all bentgrasses, is adapted to cool, moist areas of coastal regions of the United States. It is primarily used on putting greens, where it forms an attractive, low-growing, compact turf with a high-quality putting surface. It is also the most shade-tolerant of all the bentgrasses and is used on fairways where nitrogen levels are kept low. Despite the advantages of these two bentgrasses, they are not well utilized by the turf industry because of their unknown genetic diversity. This creates a great obstacle in the improvement of these species. Since these species are not exploited to the level of creeping bentgrass, there is little information available on their genetic diversity. Therefore, this needs to be explored to exploit their potential. The objectives of this research are to: 1. Use AFLP (Amplified Fragment Length Polymorphism) markers to evaluate the genetic diversity of (USDA) accessions and estimate the genetic distance of the different accessions and varieties for improving the germplasm potential, and 2. evaluate the morphological variations under greenhouse and field conditions. AFLP markers are a powerful, consistent tool for evaluating genetic diversity and for DNA fingerprinting. The results are highly repeatable and contain a very low error rate of less than two percent. This research involves 34 accessions, including 27 accessions of colonial bentgrass and 7 accessions of velvet bentgrass that were obtained from the Western Regional Plant Introduction Station (USDA) at Pullman, WA. All of the seeds are sown in cell packs and DNA will be extracted from young leaves after one month in the greenhouse or until it reaches a desirable height. After the seedlings reach a desirable height, they will be transplanted to the Iowa State Horticulture Research Farm for further studies on morphological characteristics under field conditions. All accessions will be planted in a randomized complete block design with a maximum of eighteen replications for each accession. We expect to obtain reliable information on the extent of genetic variation and genetic distances among different accessions from molecular analysis. We also expect to obtain information on morphological variations among different accessions from our field studies. Based on the data that we expect to obtain on the range of morphological variations and genetic diversity among all accessions, we will be able to select plants with desirable traits for our breeding programs. Data on morphological and genetic variations is not available at present. 40 Nick Ch Analysis of Genetic Factors Associated with Winter Hardiness in Perennial Ryegrass Shui-zhangFei and Reed Bar Yanwen Xiong, In recent decades, the use of perennial ryegrass has seen significant increases, largely due to its improved genetic color, texture, density, and environmental stress tolerance. The fast establishment rate, excellent seedling vigor, and good wear tolerance make it a good choice for use on golf course fairways and athletic fields. One disadvantage of using perennial ryegrass, however, is that it does not have adequate cold hardiness to survive severe winters in the northern part of USA including Iowa. Therefore, development of improved cultivars or germplasm of perennial ryegrass with enhanced winter hardiness would greatly benefit the turfgrass industry in Iowa as well as in northern USA. Winter hardiness of perennial ryegrass is a complex trait that is controlled by multiple quantitative genes with each gene having minor phenotypic effects. Because of the environmental effect and the interaction between genes controlling winter hardiness and the environment, it would be difficult to identify these quantitative genes through conventional genetic methods. DNA molecular markers, however, offer a great promise to identifying genes responsible for winter hardiness. There are abundant DNA marker variations that exist in natural plant populations; some of these markers are in the same chromosome as the genes that are responsible for winter hardiness. Often these markers transmit together with the winter hardiness genes into their progenies. Unlike the winter hardiness genes that may be difficult to identify due to the environmental influence, DNA molecular markers are stable and relatively easy to identify. The long-term goal of this project is to efficiently select winter hardy perennial ryegrass germplasm with marker-assisted selection (MAS). The objective of this research is to use molecular biology tools to identify molecular markers that are closely associated with winter hardiness in perennial ryegrass. In addition, molecular markers that are closely associated with other important agronomic traits including rooting, growth habit, etc., will also be investigated. Research methods P la n t m aterials A segregating population of 174 genotypes was created by crossing a perennial ryegrass cultivar ‘Manhattan’ with an annual ryegrass cultivar ‘Floregon’. While ‘Manhattan’ has good winter hardiness, ‘Floregon’ is very sensitive to winter killing. This population was maintained in our research greenhouse at 20-21°C and fertilized with Miracle Gro to prevent nutrient deficiency. Irrigation was provided as needed. Four clones of each genotype were planted within each replication in an a lattice design with three replications. The distance between individual clones of a genotype is 30cm, and the distance between each genotype is 60 cm. The distance between rows is 90 cm. Component traits of winter hardiness will be measured. These will include traits such as fall growth after the last cutting, LT50 (the temperature at which half of the plants die), visual scores for winter injuries, tiller angles, root morphology including depth, root dry weight, the ratio of root dry weight / shoot dry weight and other chemical components. DNA marker profiles for each genotype have been obtained at Oregon State University. M ea su rem en ts This project was started in the spring of 2003. Single factor analysis of variance will be computed for each marker and trait combination once data for each measurement becomes available. The trait values of all individuals having a marker will be compared with those without this marker by using an F-test. Multiple regression analysis will be performed with data for all markers to identify the best polygenic models for each trait. D a ta an alysis *Reed Barker, Research Geneticist, USDA-ARS, Oregon State University, Corvallis, OR 41 Determination of Reproductive Mode of a USDA Core Collection of Kentucky Bluegrass Robert Wieners and Shui-zhang Fei Introduction Kentucky bluegrass ( P oa p ra ten sis) is an important turf species with a rather unique reproductive process. The ability of certain plants of Kentucky bluegrass to reproduce via seed asexually is called apomixes. Highly apomictic cultivars are very desirable to reduce plant-to-plant variation within a turf stand. Therefore, the ability to identify apomictic plants for breeding purposes is important. In this study, we chose a USDA core collection, which contains germplasm from many locations that have been shown to be genetically diverse. These collections could prove to be a useful source of genetic diversity for desired traits in breeding programs. Materials and Methods A USDA core collection with 38 accessions from 14 different countries was selected for analysis. The procedure for analysis comes from Matzk et.al. (2000.) A flow cytometer was used to determine DNA content in picograms for somatic tissue (leaf tissue). Reproductive mode was determined by analysis of mature seed. By comparing the relative positions and amplitude of the means of the nuclei peaks from the flow cytometry data, a model can be constructed based on known reproductive processes within Kentucky bluegrass. These models appear in Table 1. The data from the flow cytometry measurements appear in Table 2. After analysis, plants were planted during October 2002 at the ISU Horticulture Research Farm for further evaluation of breeding potential. Table 1. Pathways of recombination that could be constructed from the C values of embryo and endosperm nuclei of Kentucky bluegrass. Female gametes C values in histogram 1 2C + (3C) Reduced Unreduced Zygotic X Endosperm X Male gametes Parthenogenic Fertilized Autonomous Reduced X X 2C + (5C) 1C + (3C) Embryo Unreduced Seed formation X X Sexual, reduced sperms X X X Pseudogamous, reduced sperms X X X Reduced, Parthenogenic 1Endosperm values in parentheses. From Matzk et. al. (2000)_______ Results Several reproductive modes are present within the 38 accessions tested. The majority of accessions possess both sexual and apomictic seed. Sexual reproduction and Pseudogamous seed formation were the most prevalent, however, some accessions did exhibit parthenogenic seed formation. The mean DNA content of the accessions also confirms that the collection is relatively genetically diverse. Works cited Matzk, F. Meister, A. Schubert, I. An efficient screen f o r reprodu ctive p ath w ays using mature seed s o f m onocots and dicots. The Plant Journal, 2000. 21 (1), 97-108. 42 Table 2. DNA content and reproductive model of the accessions of the core collection. Mean DNA content1 Reproductive Model Accession Origin (c values) (Pg) 2.74 2c (3c) Switzerland 1 2 Turkey 6.02 2c (3c) (5c) 3 Iran 7.25 2c (3c) (5c) 4 Iran 10.97 (16.56) 2c (3c) (5c) 5 Spain 7.30(11.82) 2c (3c) (5c) 6 Canada 11.40 (9.20) 2c (3c) (5c) 7 Iran 7.37 (10.97) 2c (3c) (5c) 8 Czech Republic 6.92(10.26) 2c (3c) (5c) 9 Hungary 4.85 (6.29) 2c (3c) 10 11 Spain 7.30 (9.76) 2c (3c) (5c) Sweden 10.79 (5.34) 2c (3c) (5c) 12 Norway 9.33 2c (3c) (5c) 13 USA (Alaska) 10.73 le 2c (3c) 14 USA (Alaska) 9.18(11.59) 2c (3c) (5c) 15 USA (Alaska) 8.07 (12.49) 2c (3c) (5c) 16 USA (Alaska) 10.18 2c (3c) (5c) 17 USA (Alaska) 9.41 2c (3c) (5c) 18 USA (Alaska) 8.89(14.57) 2c (3c) (5c) 2c (3c) (5c) 19 USA (Alaska) 7.22 20 USA (Alaska) 8.39 le 2c (3c) 21 USA (Alaska) 8.32 2c (3c) (5c) 22 USA (Alaska) 8.42(15.16) 2c (3c) (5c) 23 India 9.28 (14.54) le 2c (3c) 24 USA (Alaska) 7.37 2c (3c) (5c) 25 Netherlands 9.32 (13.07) le 2c (3c) (5c) 26 USA (Alaska) 10.79 (15.70) 2c (3c) (5c) 27 USA (Alaska) 9.75 2c (3c) (5c) 28 USA (Alaska) 8.09(11.75) 2c (3c) (5c) 29 USA (Alaska) 9.73 2c (3c) (5c) 30 Spain 10.11 2c (3c) 31 Kazakhstan 9.27 2c (5c) 32 Russia 6.60 (9.92) 2c (3c) (5c) 33 Russia 7.19 2c(3c)(5c) 34 Russia 6.74 2c (3c) (5c) 35 USA 6.24 2c (3c) (5c) 36 USA 6.36(11.12) 2c (3c) (5c) 37 USA 9.73 2c (3c) (5c) 7.8 2c (3c) (5c) 38 USA 1 DNA content of majority (minority) of plants sampled. 2 Observed peaks from flow cytometry histogram embryo (endosperm). 43 Perennial Ryegrass Breeding Research 2001-2002 Robert Wieners and Shui-zhang Fei Objective The use of perennial ryegrass has seen significant increases in recent decades, largely due to its improved genetic color, texture, density and environmental stress tolerance. The fast establishment rate, excellent seedling vigor, good wear tolerance and the ability of perennial ryegrass to compete with P oa annua makes it a good choice for use on golf course fairways and athletic fields in Iowa. However, most of the elite perennial ryegrass cultivars do not have adequate winter hardiness to survive severe winters in the northern USA, including Iowa. The goal of this research was to develop new perennial ryegrass germplasm with improved cold tolerance for better persistence in northern climates. The specific objectives of this project were to: 1. screen a USDA perennial ryegrass collection for stress tolerance, and 2. make crosses between improved varieties and wild materials possessing desirable traits and select superior individual plants within the progeny. By utilizing the diversity present in USDA collections, unique germplasm may be created for utilization in turfgrass breeding programs. Research progress F ie ld resea rch One hundred and five accessions of perennial ryegrass collected primarily from temperate regions worldwide and two improved cultivars of “Accent” and “Caddieshack’ were planted at the ISU Horticulture Research Farm in 2001. Each accession was sown in a 4ft by 4ft plot with three replicated blocks. In the following spring (2002), cold hardiness was assessed by visually evaluating the stand persistence. Although the 2001 winter was considered mild in Ames, some accessions were winter-killed. Sixty-seven out of 105 wild accessions survived and appeared to possess adequate cold tolerance for further investigation. The 67 accessions were scored based on color, texture, and density and then compared to die cultivars Caddieshack and Accent. As a result, plants from 14 accessions with superior traits were selected and taken to the greenhouse for crossing. Meanwhile, the 67 accessions in the field were allowed to grow to maturity in order to evaluate seed production potential. The plots were then gradually mowed down to a normal turf height of 2.75 inches. After a month of regrowth, opportunistic traits were scored which included rust and leaf spot infestation. Each trait was scored once at the height of infestation and compared to the improved cultivars of Accent and Caddieshack. In addition to disease screening, mowing quality data was obtained. Plots were allowed to grow per typical turf conditions and mowed to approximately 2.75 inches. The amount of leaf tearing was scored and compared to Accent and Caddieshack. From this data, more selections were made. Five additional accessions that exhibited good mowing quality were selected and taken to the greenhouse. G reen h ou se research Four individual seeds from each accession were also grown in the ISU horticulture greenhouse to screen for seed germination time, shoot development, density and regrowth potential in 2001. In 2002, individual plants were cut several times to score regrowth again. Plants were also screened during the summer of 2002 for heat tolerance. The data obtained from greenhouse experiments resulted in the selection of seven additional accessions for further research. Each of the original 14 selected accessions were crossed with either Accent or Caddieshack in controlled-pollination. Seeds were then harvested and three progeny of each cross were grown in the greenhouse and transferred to the field for evaluation on cold hardiness, persistence, color, texture, and density. Conclusions As a result of the data obtained to present, 26 of the original 105 accessions were chosen for further research. Plants are chosen based upon cold tolerance first, then by three additional criteria. The first group consists of 14 accessions selected based upon color, texture, and density. The second group consists of 5 additional accessions selected based upon mowing quality. The third group consists of another set of accessions selected based upon heat tolerance and regrowth potential. Although most of the accessions that were chosen appeared to have lower quality than Caddieshack and Accent, some accessions had a trait that was comparable. This, however, is not surprising, because most of the accessions, if not all, had never been subjected to human selection, but these accessions may have better cold tolerance that can be incorporated into existing elite perennial ryegrass germplasm. 44 Changes in Carbohydrate Metabolism in Response to Mowing Mark Howiesonand Nick Christians Mowing is a common cultural practice essential to maintain dense, uniform, and appealing turfgrass. Mowing is defoliation, and therefore, removes leaf tissue that plants use to capture light energy from the sun. Captured light provides energy for the production of organic molecules, such as proteins and carbohydrates. Regrowth and initiation of new leaf tissue after defoliation is important to develop a new photosynthetic surface required for the production of carbohydrates. Carbohydrate and nitrogen reserves provide energy and raw materials for shoot and leaf regeneration. The most abundant carbohydrates in creeping bentgrass are fructose, glucose, sucrose, and ffuctan. Fructose and glucose can be consumed to provide energy or incorporated into reserve carbohydrates when energy is abundant. Sucrose is transported via the phloem from source to sink tissues and it is broken down into one fructose and one glucose. Fructan is a reserve carbohydrate found in creeping bentgrass and is composed primarily of fructose molecules. The objective of this study was to determine how fructose, glucose, sucrose, and fructan concentrations change over time in response to defoliation. Creeping bentgrass seeds were planted in 14 x 20 inch flats filled with sand and grown in a greenhouse. High-pressure sodium lamps provided a 16-hour photoperiod. The sand was fertilized weekly with a modified Hoagland’s solution that supplied 0.75 lbs of nitrogen per 1000 ft2 per month. Grass was clipped three times a week at a height of 0.5 inch with an electric reel mower prior to the initiation of the study. There were four mowing height treatments. Grasses were clipped at 0.50, 0.35,0.20 inches and not mown. Following mowing treatments, approximately 1.5 grams of stubble tissue were collected every 24 hours for 72 hours. A subsample was dried at 68°C for three days for dry weight analysis, the remaining tissue was frozen and ground in liquid nitrogen. Ground samples were stored at -20°C until further analysis. Carbohydrates were extracted by placing the frozen tissue into 8 mL of boiling 80% ethanol for one hour. The supernatant was poured off and 5 mL of boiling water was added to the grass tissue. The tissue was extracted in the water for 1 hour and the aqueous supernatant was poured off and pooled with the ethanolic supernatant. The pooled supernatants were evaporated to dryness using a rotary evaporator and the insoluble residue was dissolved in 5 mL of water. Carbohydrate concentration was determined by high performance liquid chromatography (HPLC) using a Sugar Pak I column and a refractive index detector. The mobile phase was 0.1 mM CaEDTA in water. The flow rate was 0.5 mL/minute and the column was heated to 90°C. Inulin, sucrose, fructose, and glucose were used as standards. The study was in a completely randomized design with three replications per treatment. Fisher’s LSD (p=0.05) was used to separate means. Fructan concentration declined in grass clipped at 0.35 and 0.50 inches for 48 hours after mowing (Figure 1). Fructan concentrations 72 hours after mowing were similar to those observed at the start of the study. Grasses clipped at 0.20 inch had the lowest fructan concentration at all sampling times and fructans did not accumulate 48 hours after mowing as they did in grasses mown at 0.50 and 0.35 inches (Figure 1). No differences were observed in sucrose concentration among the four mowing treatments (Figure 2). Grasses mown at 0.20 inches consistently had the lowest glucose and fructose concentrations over the 72-hour study (Figure 2 and 3). These results emphasize the importance of not removing more than 1/3 of shoot tissue in a single mowing. Grasses mown at 0.20 had approximately 60% of above ground tissue removed and remained chlorotic for several weeks after mowing. These plants consumed large quantities of carbohydrates to recover from mowing stress. Grasses mown at 0.35 inches had 30% of above ground tissue removed by mowing. These plants were able to recover rapidly from the mowing stress by consuming stored carbohydrates to provide energy for regrowth. Future research will examine the quantities and activities of enzymes responsible for synthesis and catabolism of fructan, sucrose, glucose, and fructose. This research will further our understanding of how mowing affects carbohydrate metabolism. 45 Figure 1. Fructan concentration over time o f creeping bentgrass after defoliation Figure 2. Sucrose concentration over time o f creeping bentgrass after defoliation 46 Time (hours) Figure 4. Fructose concentration over time o f creeping bentgrass after defoliation 47 Timing of Roundup® Application Critical when Converting Golf Course Greens and Fairways to Roundup® Ready Creeping Bentgrass Luke Dant, Nick E. Christians and Shui-zhang Fei Introduction Roundup® Ready creeping bentgrass (RRCB) could be the golf course superintendent’s key to eliminating the invasion of seemingly uncontrollable weed species, particularly P o a annua , in golf course greens and fairways. Roundup® is considered to be a relatively safe herbicide to both the handler and the environment while at the same time providing superior weed control. Additionally, an integrated weed management program based on the use of Roundup® herbicide could be a cost effective alternative to conventional weed control methods. Unfortunately, the complete renovation to RRCB would be costly and would render a golf course unplayable for a significant period of time. If it was possible to incorporate the overseeding of RRCB into regular maintenance processes, such as verticutting and aerification, existing greens and fairways could slowly be converted to RRCB. This would therefore eliminate costly renovation and the interruption of play. The overall goal of this project is to determine at what time, in relation to the overseeding of RRCB, that the Roundup® susceptible turf should be removed with Roundup®, so that a successful conversion to RRCB can be achieved. This ideal time would minimize disturbance to the playing surface while still maintaining a satisfactory appearance of the golf course green or fairway. Site The study is being conducted at Veenker Memorial Golf Course in Ames, Iowa on one green and three fairways built on native soil. This area was built with the intent to conduct research, therefore, the research plots are not in play. The green is maintained at a height of 0.145 inches and the fairways are mown at 0.60 inches. The research area contains these existing turfgrass species: > > Green > ‘Penncross’ creeping bentgrass Fairway > ‘Trueline’ creeping bentgrass > Scotts 100-81600 perennial ryegrass mix > 35.77% ‘Divine’ > 32.63% ‘Majesty’ > 29.86% ‘Enchanted’ Double Eagle Kentucky bluegrass > 29.51% ‘Apollo’ > 24.72% ‘Serene’ > 14.94% ‘Coventry’ > 14.88% ‘Envicta’ > 14.79% ‘Blackstone’ Methods The following treatments where selected in order to accomplish the goal of this study. All treatments were replicated three times on the putting green and three times on each fairway. It should be noted that during the breeding process, a yield of only 50% RRCB is achieved, whereas the other 50% is conventional bentgrass. The Scotts Company recommends that a Roundup® application be made 4 weeks after seeding to eliminate competition from conventional bentgrass plants that are Roundup® susceptible. C om plete R en ovation Treatment 1 acted as a control in which a bare soil seedbed was prepared. As with the other treatments, RRCB seed was applied at a rate of 1.75 lb per 1000 sq. ft. 1. Apply Roundup® two weeks before seeding, remove sod and prepare seedbed, apply Roundup® again four weeks after seeding to remove Roundup® susceptible seedlings 48 C on version U sing A erifica ito n a n d V erticu ttin g Green Treatments 2-11 of the green study were core aerified in two directions using 5/8-inch tines and the aerification cores were harvested. The area was then verticut and topdressed to fill all aerification holes. RRCB seed was applied at a rate of 1.75 lb per 1000 sq. ft. To obtain good soil-to-seed contact the plot was lightly verticut and spiked. Fairways Core aerification with 5/8 tines took place on treatments 2-11 in two directions and the cores were broken up using a verticuter. The area was then dragged and seeded at a rate of 1.75 lbs RRCB seed per 1000 sq. ft. As with the green, the plot was lightly verticut and spiked. 2. No Roundup® application treatment during current growing season 3. Apply Roundup® one week prior to seeding and apply Roundup® again four weeks after seeding 4. Apply Roundup® at time of seeding and apply Roundup® again four weeks after seeding 5. Apply Roundup® one week after seeding with no additional Roundup® applications during the same growing season 6. Apply Roundup® one week after seeding with an additional Roundup® application four weeks after seeding 7. Apply Roundup® two weeks after seeding with no additional Roundup® applications during the same growing season 8. Apply Roundup® one week after seeding with an additional Roundup® application four weeks after seeding 9. Apply Roundup® four weeks after seeding with an additional Roundup® application four weeks after seeding 10. Apply Roundup® at the end of the growing season 11. Apply at one fourth of the recommended rate of Roundup® at seedling emergence; apply three repeated applications of Roundup® at one fourth of the recommended rate at a two week intervals (to suppress and gradually remove the existing grass). Current Status of the Study The study was started on August 17,2002 and was seeded on September 3,2002. On May 7,2003 all of the plots were sprayed with Roundup® to determine the actual population of RRCB plants in each plot. Subsequent Roundup® applications will be made to the entire study during the current growing season to remove any unwanted plant species. This research project will conclude at the end of the 2003 growing season and the results will be placed in the 2004 Iowa State University Research Report. 49 Cation Ratios and Soil Testing Methods for Sand-Based Golf Course Greens St.John, Nick Christians, Henry Taber Rodney This research is being supported by a grant from the USGA. Introduction: The current recommendation for golf course greens construction is to utilize a sand root-zone mix. These sands have low cation exchange capacities (CEC), ranging from less than 1 to 6 cmolc'kg"1. With so few cation exchange sites available, applying the correct amount of fertilizer to provide adequate plant nutrition without causing nutrient leaching can be difficult. To further complicate the problem, the sand used for greens and athletic field construction is often derived from limestone and is termed calcareous. Calcareous sands are found throughout the United States. Calcareous soils have been extensively studied on agronomic crops established on soils with large proportions of clay, silt and organic matter and relatively high cation exchange capacities. Very little work has been done to relate turfgrass growth and development with the low CEC-sands used for golf course greens. Goal: To develop a set of standard methods and models to be used in analyzing turfgrass soil samples, especially for calcareous sand samples. To gain better understanding of cation ratios used for making fertilizer recommendations. Accurate recommendations will help develop best management practices that increase overall turfgrass health and protect the environment. Objectives: 1. To evaluate and correlate several existing soil extraction methods with tissue analysis to determine which type of extractant is best for sand based turfgrass systems. 2. To modify, if necessary, existing extraction methods to better suit turfgrass soil types. 3. To better understand how the BCSR theory and Ca/Mg/K ratios apply to turfgrass systems. 4. Improve current recommendations for Ca/Mg/K fertilization of turfgrass. Research Methodology: S o il T estin g M e th o d s : A greenhouse experiment will be started to evaluate different extraction methods and gain further knowledge about different Ca/Mg/K ratios. Four different levels of each Ca, Mg, and K will be applied to creeping bentgrass established on calcareous or silica sand. Soil and tissue samples will be taken and analyzed for nutrient content using an Inductive Coupled Argon Plasma (ICAP) machine, which can analyze 12 different nutrient concentrations. The different extraction methods will be correlated with tissue analysis and applied fertilizers. Moreover, tissue and soil samples will be collected from several golf courses and other turf areas with varying soil type, and the soil testing methods will be correlated with tissue tests. C a /M g /K R atios: The same greenhouse experiment listed above will try to establish different basic cation ratios. Some preliminary work will be done to determine the best methodology for establishing and maintaining the different cation ratios. As of now, we are planning to use 4 different levels of each Ca, Mg, and K to make 12 different cation ratios. Creeping bentgrass will be established on either calcareous or silica sand. Clippings and soil samples will be collected and analyzed monthly. Tissue, soil test results, and quality ratings will be correlated to evaluate the differing cation ratios. Treatm ents • One Grass: creeping bentgrass • Two Sand Types: calcareous and silica sand • Three different nutrients: calcium, magnesium and potassium • Four different levels of each nutrient: low, medium low, medium high and high Expected Results: Initiate or develop use of better analysis techniques for soil nutrient testing of sand-based turfgrass systems. Improved understanding of Basic Cation Saturation Ratio Theory and Ca/Mg/K ratios used for fertilizer recommendations. 50 Development of Remote Sensing Techniques to Determine Moisture and Nutrition Stress J. K. Kruse, N. E. Christians and M. H. Chaplin Turfgrass managers must continually monitor their fertilization and irrigation programs to ensure optimal appearance while minimizing losses to the environment and maximizing profit. Characterizing the spatial variability of nutrient and moisture status across a golf course or large sports facility requires careful observation and collection of many soil and tissue samples. Optical remote sensing techniques have been shown to be valuable tools in quickly and reliably identifying stressed plants through the use of various vegetative indices derived from reflectance data collected from the crop canopy. Extensive research has been conducted investigating vegetative indices as they relate to the nutritional and moisture status of various agricultural crops with intriguing results. Handheld remote sensing systems are already being used in evaluating the chlorophyll content of turfgrass stands, which in turn is related to the quality of the turfgrass being grown. The use of remotely sensed data may prove to be a valuable tool in the modification of traditional irrigation and fertility programs to reduce inputs and improve environmental quality. The potential exists for the use of an optical remote sensing system to provide maps indicating the moisture and nutritional status of large turfgrass areas, thus enabling the use of site-specific management techniques which will reduce the application of fertilizers and irrigation. The objectives of this research are to: 1) Evaluate various indices reported in the literature as tools for identifying moisture and nutrient stressed turf, 2) Develop new indices to be used in detection of moisture and nutrient deficiencies, and 3) Determine differences in spectral response of Creeping Bentgrass, Kentucky Bluegrass, and Perennial Ryegrass. This interim report will focus on some of the studies conducted to date involving remote sensing of turfgrass nitrogen and potassium status. The nitrogen and potassium studies were organized in a randomized complete block design with four replications each. Each replication in the nitrogen study consisted of three treatments: 0.0, 0.5 and 1.0 lbs N/1000ft2/30d applied as urea with all plots receiving 0.1 lbs P/1000ft2/30d and 0.5 lbs K/1000ft2/30d applied as phosphoric acid and potassium chloride respectively. Each replication in the potassium study consisted of three treatments: 0.0,0.5 and 1.0 K/1000ft2/30d applied as potassium chloride with each plot receiving 0.1 lbs P/1000ft2/30d applied as phosphoric acid and 1.0 lbs N/1000ft2/30d applied as urea. Treatments were split into two applications once every two weeks, and applied in solution using a C 0 2backpack sprayer calibrated to apply 3.0 gallons of water/1000ft2. Irrigation was applied immediately following treatments to reduce the risk of fertilizer bum. The study area consisted of ‘Penncross’ creeping bentgrass (A grostis p a lu stris Huds.) established on a USGA sand-based green. Evaluation of turf quality was made twice a month, coinciding with the collection of remotely sensed data. Quality was ranked on a scale of 9 to 1; with 9=best, 5=lowest acceptable and l=worst. Optical remote sensing data was collected twice monthly using an OceanOptics SD1000 spectrometer mounted on a self contained cart equipped with a hood to block out ambient sunlight and halogen bulbs to provide a consistent source of illumination on the turf. This system was designed to eliminate the problems typically associated with differences due to shade, which is a common occurrence on many turfgrass areas. The spectrometer was calibrated to measure reflectance from 3501150 nm with a resolution 1.0 nm. The following growth and stress indices were also evaluated: 1. 2. 3. 4. 5. 6. 7. 8. NDVT growth indice computed as R850 - R680/R850 + R 680 SRI stress indice computed as R950/R899 SR2 stress indice computed as R695/R419 SR3 stress indice computed as R695/R759 SR4 stress indice computed as R550 - R600/R800 - R899 SR5 stress indice computed as R630/R489 SR6 stress indice computed as R370/R489 SR7 stress indice computed as R370 + R630/R490 + R799 Tissue was harvested once monthly following collection of remotely sensed optical data and analyzed for plant nutrient content using standard Total Kejhdahl Nitrogen and Inductively Coupled Argon Plasma Spectroscopy plant analysis procedures. Nitrogen Content vs. Reflectance The growth and stress indices were correlated with turf quality, percent nitrogen in the tissue, and chlorophyll content to determine if there was any relationship between them. There was a strong correlation between percent nitrogen in the tissue and the Normalized Difference Vegetation Index (NDVI), SRI and SR3 indices (r = 0.76, -0.68 and -0.79 respectively). The other indices investigated did not correlate well with percent nitrogen, though SR5, SR6 and SR7 correlated with chlorophyll content in the tissue (r = 0.67, -0.75 and 0.74 respectively). NDVI and SR3 also showed a strong correlation with quality (r = 0.80 and -0.83 respectively) (Table 1). 51 Table 1. Correlation coefficients for reflectance vs. quality, percent nitrogen and chlorophyll content for the nitrogen study. Chlorophyll Content Percent Nitrogen Quality Wavelength t NDVI 0.76 -0.10 0.80 -0.68 -0.40 -0.58 SRI 0.03 SR2 -0.55 0.16 0.22 -0.79 -0.83 SR3 -0.07 -0.60 SR4 -0.57 -0.24 -0.36 0.67 SR5 -0.75 -0.40 -0.12 SR6 -0.04 -0.74 -0.36 SR7 t Percentage of reflectance at selected wavelength ratios. Potassium Content vs. Reflectance There was little correlation between potassium content of the tissue and the growth and stress indices investigated in this study (Table 2). However, SRI, SR2, SR5, SR6 and SR7 showed high correlation with chlorophyll content of the tissue (r = -0.61, -0.78, 0.74, -0.78 and ■ 0.79 respectively) (Table 2). Table 2. Correlation coefficients for reflectance vs. quality, percent potassium and chlorophyll content for the potassium study. Chlorophyll Content Percent Potassium Quality Wavelengthf 0.20 0.17 0.18 NDVI -0.28 -0.61 -0.20 SRI -0.78 -0.03 SR2 0.26 -0.54 -0.34 -0.37 SR3 -0.32 -0.14 SR4 -0.11 0.74 -0.12 -0.17 SR5 -0.02 -0.28 SR6 -0.23 -0.79 -0.01 SR7 -0.31 f Percentage of reflectance at selected wavelength ratios. Discussion Spectral data appears to be able to discriminate between plots of various qualities when the visual symptoms are obvious, such as those resulting from various nitrogen treatments. It was not surprising to find little correlation between quality and the various indices due to the visual similarities between all the potassium treatments. Several indices showed a correlation with chlorophyll content in both studies, which may prove to be valuable in accessing overall turf quality due to the fact that increasing concentrations of chlorophyll result in a greener turfgrass, which is often associated with higher quality. The strong correlations between the reflectance ratios and nitrogen content indicate the possibility that this technology might be successfully utilized in managing turfgrass nitrogen programs on a site-specific basis. In addition to the two studies whose preliminary results are discussed here, several moisture studies have been conducted investigating the use of the remote sensing equipment to evaluate the moisture status of turfgrass plants growing under fairway conditions on a golf course. Work is also being done to evaluate the influence of soil amendments on spring green-up and heat stress on the reflectance qualities of a turfgrass stand. 52 Evaluation of Methylene urea Rate and Mixing Depth for Growth and Establishment of pratensis L. on Sand-based Systems S.K. Lee, D. D. Minner, N. E. Christians and H. G. Taber Introduction The fundamental concept o f a slow-release fertilizer is that it releases its nutrients at a more gradual rate that allows maximum uptake and use o f nutrients by plants while minimizing the losses due to leaching, volatilization, or unnecessary turf growth (Sartain, 2002). This may reduce the number o f fertilizer applications required to maintain plant growth at desired levels and allow greater rates o f fertilizer to be applied in a single application. Slow- and controlled-release N sources reduce leaching potential under adverse climatic and edaphic conditions as well as provide other benefits such as reduced bum potential, extended release over time, and lower labor costs (Fry et al., 1993). Methylene ureas are a class o f slow-release N that were promoted during the 1960’s and 1970’s (Sartain, 2002). These products predominantly contain intermediate-chain-length polymers. The total N content o f a methylene urea polymer is 39 to 40%, with between 25 and 60% o f the N present being cold-water insoluble N (CWIN) (Christians, 1998). Unreacted urea N content generally is in the range o f 15 to 30%. The objective o f this study was to compare urea and methylene urea (Nutralene®) by measuring clipping dry weight, root dry weight, root organic matter, and amount o f N 0 3-N leached from a soil column at 146 and 293 kg*ha_1 and four mixing depths (0, 7.6, 15.2, and 22.9 cm) on a sand-based system. Materials and Methods This study was conducted for 12-weeks in a greenhouse at Iowa State University. Ames, Iowa. The experimental design was a randomized complete block with 16 treatments and four replicates. Methylene urea (Nutralene®), a slow-release N source, and urea (46-0-0), a fast-release N source, were the N sources. Both materials were evaluated with four mixing depths o f 0, 7.6, 15.2, and 22.9 cm and evaluated with two application rates (146 and 293 kg*ha_1). Urea for surface application was applied weekly at 12.17 and 24.42 kg*ha_1, giving a total o f 146 and 293 kg «ha1during the 12-week study period, respectively. Local mason’s sand that met the United States G olf Association (USGA) specification was used as the growing medium (USGA Green Section Staff, 1993). The sand was packed into a 7.62 cm diameter polyvinyl chloride (PVC) pipe lined with a clear plastic sleeve. The PVC pipe was capped at the bottom, and the plastic sleeve tied o ff at the bottom with fine holes punched into it facilitate drainage while keeping the sand in place. The plastic sleeve had a length o f 38.1 cm, and the root zone depth was 30.5 cm. The columns were sodded with mature sod o f Poa pratensis L. harvested and watered 300 ml each week. Greenhouse temperature during the night and day was 19.4-22.2 °C, respectively. Modified Hoagland solution was used that enabled proper levels o f nutrients to be maintained in the root zone (Pellett and Roberts, 1963). The N fertilizers were applied on 4 Nov. 2002. Grass clippings were taken from each tube at two-week intervals. At the end o f the study, root dry weight and organic matter weight for roots were measured. All leachate was collected from the cup under the PVC pipe for final nutrient analysis. Nitrate-N o f the leachate was analyzed by using the cadmium-reduction method (Bremner, 1965). Data were subjected to analysis o f variance by using the Analysis o f Variance (ANOVA) procedure, and mean separation was performed by the least significant difference (LSD) method wit the Statistical Analysis System (SAS, 1987). Results Significant effects on clipping dry weight were found in all treatments and interactions with exception o f N rate X mixing depth and N source X N rate X mixing depth (Table 1). For this reason, each factor was reported independently at each mixing depth o f the other factors (Table 2). In 0 cm mixing depth, both o f urea and Nutralene® had no difference within same rate. However, Nutralene® o f 293 kg-ha'1 rate produced 96-437 % more clipping dry weight than urea o f 293 kg*ha_1 rates in 7.6, 15.2, and 22.9 cm mixing depth. Nutralene® o f 146 kg*ha_1 rate had 142 % clipping dry weight than urea o f 146 kg »ha1 rate in 7.6 cm mixing depth. There were significant main effects and interaction effects o f N source X mixing depth observed on root dry weight and root organic matter (Table 1). Urea at a rate o f 293 kg*ha_1 rate resulted in more root dry weight and root organic matter than Nutralene® at the 293 kg-ha"1 rate applied at the 0 cm mixing depth. Conversely, Nutralene® at a rate o f 293 kg*ha_1 rate produced more root dry weight and root organic matter than urea o f 293 kg*ha1 rate applied at the 7.6 cm mixing 53 depth. Nutralene® at a rate o f 146 kg »ha-1 rate had 72 and 63 % more root dry weight and root organic matter, respectively than urea at a rate o f 146 kg»ha1 rate applied at the 15.2 cm mixing depth. No N source and rate effects for N 0 3-N release was found in 0 cm mixing depth. Interestingly, the 146 kg*ha-1 Nutralene® rate provided less leached N 0 3-N with more clipping dry weight, root dry weight, and root organic matter than plants that received urea at 146 kg#h a 1 applied at the 7.6 cm mixing depth. Nutralene® at a rate o f 293 kg-ha'1 rate at the 22.9 cm mixing depth also produced 18 ppm leached N 0 3-N with more clipping dry weight, root dry weight, and root organic matter compared to urea at a rate o f 146 kg »ha1 rate in 22.9 cm mixing depth that produced 174 ppm leached N 0 3-N. Literature Cited Bremner, J.M. 1965. Inorganic forms o f nitrogen. 1179-1237. In C.A. Black et al. (ed.) Method o f soil analysis. Part 2, Argon. Monogr. 9. ASA, Madison, WI. Christians, N.E. 1998. Fundamentals o f turfgrass management. Ann Arbor, MI. Fry, J.D., D.O. Fuller, and F.P. Maier. 1993. Nitrogen release from coated ureas applied to turf. International Turfgrass Society. 7:533-539. Pellett, H.M. and E.C. Roberts. 1963. Effects of mineral nutrition on high temperature induced growth retardation of Kentucky bluegrass. Agron. J. 55:473-476. Sartain, J.B. 2002. Foot for turf: slow-release nitrogen. Ground Maintenance. SAS. 1987. SAS/STAT User’s Guide. Version 6. Statistical Analysis System Institute, Inc., Cary, NC. United States Golf Association Green Section Staff. 1993. USGA recommendations for a method of putting green construction. USGA Green Section Record. 1-3. Table 1. Summary o f analysis o f variance indicating significant source effects on total clipping dry weight, root dry - ~ * --------------- * ' Source N-source (NSO) N-rate (NRT) Mixing depth (MD) NSO x NRT NSO x MD NRT x MD NSO x NRT x MD j ’• Total clipping dry weight Root dry weight Root organic matter Amount of leached N 0 3-N ** * * ** ** ** ** NS 3 ** ** ** ** 1 * NS NS NS 3 ** ** ** NS 3 NS NS NS ** 3 NS NS NS * df 1 1 Significant at the 0.05 and 0.01 probability level, respectively. NS = not significant. 54 Table 2. Response o f Poa pratensis ‘Unique’ fertilized with Nutralene@or urea at two rates and four depths o f fertilizer incorporation. Values are means o f four measurements.______________________________________________________ Total clipping dry weight (g/m2) Nitrogen source Rate (kg'ha1) Nutralene® Nutralene® Urea Urea 146 293 146 293 200 331 265 385 cde2 ab be a Nutralene® Nutralene® Urea Urea 146 293 146 293 191 322 79 60 cde ab fg g Nutralene® Nutralene® Urea Urea 146 293 146 293 161 208 67 106 def cd fg efg Root dry weight (g/m2) —n 157 236 194 305 ef b bede a Root organic matter (g/m2) Leached NOj-N (PPm) 140 defgh 209 b 169 bede 265 a 17 13 9 13 d d d d 121 193 112 96 efgh bed fgh h 25 13 92 33 d d be cd 156 196 96 152 bedef be gh edefg 45 115 40 167 cd ab cd a 138 212 135 165 defgh ab efgh bedef 64 18 27 174 bed d d a -.npnfli f \ vili pm 1/vpiU —7/ •U 135 219 136 103 ef bed ef f _Dpnth L/CJJlll —tJlÇ J m? jJ pm L111 175 228 102 168 cde bed f de —J-rV npnth pm _ ^Jlll —?? QVili Nutralene® Nutralene® Urea Urea LSD (0.05) 146 293 146 293 117 324 64 123 defg ab fg defg 150 232 148 182 99 61 ef be ef bede 56 64 z Values in a column followed by the same letter are not significantly different based on LSD at 0.05 probability. 55 Evaluation of Fungicides for Control of Dollar Spot and Brown Patch in Creeping Bentgrass M.L. Gleason, S.J. Helland, and J.P Newton Department o f Plant Pathology and Veenker Memorial G olf Course Iowa State University Trials were conducted at Veenker Memorial Golf Course in Ames, Iowa in 2002. Creeping bentgrass was maintained at 0.16-inch cutting height. Fungicides, selected for activity against brown patch, were applied using a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal per 1,000 sq ft. The experimental design was a randomized complete block with four replications. All plots measured 4 ft x 5 ft. Because several treatments were added to the trial after it began, spray applications were initiated on 20 Jun, 28 Jun, and 21 Aug. These were followed by re-applications at recommended intervals until 11 Sep. Data were analyzed using the GLM procedure in SAS, and mean separations were determined using Fisher’s protected LSD at P<0.05. Disease pressure was moderate to severe for Dollar Spot and Brown Patch. Most of the tested products suppressed both diseases significantly (P<0.05) in comparison to the unsprayed check. No phytotoxicity symptoms were observed during the trial. Interval (days) 26 Jun______________10 Jul_____________ 2 Aug_____________ 1 Sep Brown Dollar Brown Dollar Brown Dollar Brown Dollar Patch2 Patch Patch Spot Patch Spot Spoty Spot LO ab 29.0 a 3.4 a 5.5 ab 3.5 a 16.7 a 5.0 a 34.2 a 0.2 be 0.4 f 3.2 ab 0.7 de 11.7 ab 0.0 d 15.7 ab 21.4 a 0.0 b 2.5 a-c 0.3 c 0.0 d 0.0 c 0.0 c 0.0 b 1.0 c-f 0.1 f 0.5 c 0.0 d 0.0 c 0.0 c 0.0 b 0.5 b 0.5 de 9.0 a-c 3.2 a 4.5 ab 3.2 a 5.0 a 8.5 b 1.5 a 2.0 b 1.0 c-e 4.7 a 1.7 b-e 0.0 b 0.8 c 0.2 c 0.0 c 0.7 b Product and rate per 1,000 sq ft — Unsprayed check..................................... 14 Endorse WP 4 oz.................................... 14 Spectro 90WDG 4 oz............................. 3336 WP 4 oz......................................... 14 14 Spotrete F 4 oz........................................ 7 3336 WP 4 oz alt. wl Spotrete F 4 oz..... Chipco Signature 80WDG 1.5 fl oz, 14 0.0 e 0.0 d 0.0 c 0.0 c 0.0 b 0.0 f etc.x......................................................... 0.5 c Magellan SC 4.1 fl oz + Daconil Ultrex 14 1.6 b-e 2.0 be 2.5 b 4.0 b 0.5 be 3.7 b 82.5WDG 2.1 oz..................................... 1.5 b-e Magellan SC 4.1 fl oz + Chipco 26GT 0. 1 b 1.0 c-f 14 2.0 a-d 3.4 be 1.2 c 0.4 c 0.0 c 1.5 fl oz.................................................... Magellan SC 4.1 fl oz + 3336 4 oz......... 14 2.7 ab 2.7 be 0.2 d 0.0 c 0.0 c 0.0 b 0.8 ef Magellan SC 4.1 fl oz + Mancozeb 2. 1 b 14 2.2 be 5.0 a 6.5 b 0.5 be 6.2 b 75DG 4 oz............................................... 1.5 b-e X 14 Xw 4.3 a 23.0 ab 0.0 c 7.0 b 1.9 b-d Eagle DG 8 lb......................................... 14 X X 5.0 b 2.0 be 5.0 a 11.3 b 0.0 c DGPRO FVB 5.3 lb............................... X X X 14 X 0.3 be X 0.3 f AG-400 8% v/v + Latron 0.2% v/v........ X X X 14 X X 0.3 be 0.3 f AG-400 4% v/v + Latron 0.2% v/v........ X X 14 X X 0.7 a-c X 0.7 ef AG-500 8% v/v + Latron 0.2% v/v........ X 14 X X X 0.3 be X 0.3 f AG-500 4% v/v + Latron 0.2% v/v........ 2 Disease severity ratings on the following qualitative scale: 0 = no disease; 1 = 1-5%; 2 = 6-10%; 3 = 11-25%; 4 = 26-50%; 5 = >50% plot symptomatic. y Percent plot symptomatic. x Chipco Signature 80WDG + : (sequentially) Chipco 26GT2SC 4 fl oz; Triton 1.67SC 1 fl oz; Daconil Ultrex 82.5WDG 3.8 oz; Compass 50WG 0.15 oz; Triton 1.67SC 1 fl oz. w Products were applied after this rating date. 56 0.0 b 4.9 ab 0.0 b 0.0 b 9.5 a 0.0 b 0.0 b 2.2 ab 3.5 ab 8.5 a 5.7 ab 1991 Corn Gluten Meal Crabgrass Control Study - Year 12 - 2002 N. E. Christians and Lukas Dant Com gluten meal (CGM) has been screened for efficacy as a natural product herbicide and fertilizer in turf on the same plot since 1991. The study is being conducted at the Iowa State University Research Station north of Ames, IA in an area of 'Parade' Kentucky bluegrass. The soil in this experimental area is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 4.6% a pH of 6.45, 3 ppm P, and 144 ppm K. Individual experimental plots are 5 x 5 ft and there are five treatments with three replications. The experimental design is a randomized complete block. Com gluten meal is applied each year to the same plots at 0, 20,40, 60, 80, 100, and 120 lbs/1000 ft2 (Table 1). Because com gluten meal is 10% N, these rates are equivalent to 0 ,2 ,4 , 6, 8, 10, and 12 lb N/1000 ft2. The CGM is applied each year in a single early-spring preemergence application using 'shaker dispensers’. The materials are watered-in with the irrigation system. Supplemental irrigation is used to provide adequate moisture to maintain the grass in good growing condition. In 2002, applications were made on April 26. Turf quality was monitored from May 7 through October 14 (Table 1). It was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable, and 1 = worst turf quality. Weed populations were measured by either counting the number of plants or by estimating the percentage of cover per individual plot. Crabgrass infestations were determined by counting the number of plants per individual plot starting on July 31 (Table 2). Dandelion populations were assessed by counting the number of plants per individual plot (Table 3). Clover populations were determined by estimating the percentage area of each plot covered by clover (Table 4). Dandelion and clover data were taken from May 7 through September 10. Data were analyzed with the Statistical Analysis System (SAS) and the Analysis of Variance (ANOVA) procedure. Table 1. Visual quality1 o f Kentucky bluegrass treated in the 1991 Com Gluten Meal Weed Control Study. Jun Jun Aug Sep Sep May lbs CGM lbs N May 14 9 1 29 19 10 26 Material /1000 ft2 /1000 ft2 2 2 4 1 6 5 5 0 0 1 Untreated control 4 4 2 20 2 5 7 7 6 2 Corn gluten meal 8 8 4 5 5 6 3 6 3 Corn gluten meal 40 6 6 5 7 3 8 8 7 4 Corn gluten meal 60 80 8 6 6 8 6 9 9 8 5 Corn gluten meal 8 8 8 6 8 8 8 100 10 6 Corn gluten meal 12 8 8 8 6 9 9 8 7 Corn gluten meal 120 1.1 1.4 1.4 2.4 1.6 1.7 1.8 LSD0.05 !Turf quality was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable, and 1 = worst turf quality. NS = means are not significantly different at the 0.05 level. Table 2. Crabgrass counts1 in Kentucky bluegrass treated in the 1991 Com Gluten Meal Weed Control Study. lbs CGM Sept Material August July 31 19 10 /1000 ft2 0 0 2 5 1 Untreated control 20 0 4 3 2 Corn gluten meal 1 0 40 0 3 Corn gluten meal 60 0 0 0 4 Corn gluten meal 80 1 0 0 Corn gluten meal 5 100 0 2 0 6 Corn gluten meal 120 0 0 0 7 Corn gluten meal NS NS NS LSD0.05 lrThese values represent the number o f crabgrass plants per plot covered. NS = means are not significantly different at the 0.05 level. 57 Oct 14 5 6 7 7 7 8 8 NS Table 3. Dandelion counts1 in Kentucky bluegrass treated in the 1991 Com Gluten Meal Weed Control Study. June June Aug Sept May lbs CGM May July 19 14 7 1 29 31 10 Material /1000 ft2 52 21 56 47 45 0 25 30 1 Untreated control 16 19 23 23 20 15 17 11 2 Corn gluten meal 2 1 1 13 3 40 1 2 3 Corn gluten meal 1 5 2 1 60 0 1 0 4 Corn gluten meal 2 1 0 11 2 80 1 0 5 Corn gluten meal 2 1 0 0 0 100 0 0 6 Corn gluten meal 1 1 0 0 0 0 7 Corn gluten meal 120 0 14.1 20.8 14.2 LSD0.05 lrThese values represent the number o f dandelion plants per plot. NS NS NS NS Table 4. Percentage clover cover1 in Kentucky bluegrass treated in the 1991 Com Gluten Meal Weed Control Study. 1 2 3 4 5 6 7 Material Untreated control Corn gluten meal Corn gluten meal Corn gluten meal Corn gluten meal Corn gluten meal Corn gluten meal lbs CGM /1000 ft2 0 20 40 60 80 100 120 May 7 May 14 June 1 June 29 July 31 Aug 19 Sept 10 31 20 33 27 17 20 10 25 2 17 2 27 17 10 8 0 0 0 22 3 10 5 0 0 0 10 3 10 2 13 22 10 15 13 30 16 25 22 2 4 2 1 0 0 NS NS LSD0.05 lrThese values represent the area per plot covered by clover. NS = means are not significantly different at the 0.05 level. 58 NS 14.0 2 1 1 1 NS 13.2 4 19.1 1995 Corn Gluten Meal Rate Weed Control Study - Year 8 - 2002 N. E. Christians and Lukas Dant Com gluten meal (CGM) is being screened for efficacy as a natural product herbicide in turf. This long-term study began in 1995 at the Iowa State University Horticulture Research Station north of Ames, IA. The experimental plot is in established 'Ram T Kentucky bluegrass. The soil is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 4.8%, a pH of 7.1, 6 ppm P, and 170 ppm K. Prior to treatment in 1995, the percentage broadleaf weed cover within the study perimeter exceeded 50%. The experimental design is a randomized complete block design. Individual experimental plots are 10 x 10 ft with three replications. Each year com gluten meal is applied to the same plots at a yearly rate of 40 lb CGM/1000 ft2 (equivalent to 4 lb N/1000 ft2) using four different regimes of single and split applications for a total of five treatments (Table 1). Four applications of 10 lb/1000 ft2, split applications of 20 lb/1000 ft2, an initial application of 30 lb plus a sequential application of 10 lb/1000 ft2, and a single application of 40 lb/1000 ft2 are included with an untreated control. Initial applications in 2002 were made on April 26 before crabgrass germination. The second application of treatment 2 was made on June 2. The third application of treatment 2 and the second of treatments 3 and 4 were made on July 18. The final application of treatment 2 was made on August 14. The experimental plot was checked for phytotoxicity after each treatment. Turf quality data were taken weekly from spring greenup on May 8 through October 14. Visual quality was measured using a 9 to 1 scale with 9 = best and 6 = lowest acceptable, and 1 = worst quality (Table 1). Broadleaf data were taken from May 8 through September 10. Dandelion and clover were the predominate broadleaf weed species within the experimental plot. Dandelion populations were measured by counting the number of plants per plot (Table 3). Clover infestations were estimated by determining die percentage area in each individual plot covered by clover (Table 4). Data were analyzed with the Statistical Analysis System (SAS) and the Analysis of Variance (ANOVA) procedure. Table 1. Turf quality1 o f Kentucky bluegrass treated with com gluten meal for the 1995 Com Gluten Meal Rate Weed Control Study. Material 1 Untreated control 2 Corn gluten meal 3 Corn gluten meal 4 Corn gluten meal 5 Corn gluten meal Rate lb product/1000 ft2 NA 10 fb 10 fb 10 fb 10 20 fb 20 30 fb 10 40 L S D q.05 May 9 May 14 Jun 6 8 8 8 4 7 7 7 8 8 8 6 3 2 3 3 7 6 7 NS NS NS 1.7 NS 4 2 7 7 7 7 7 7 7 7 7 6 1.9 1.3 6 Jun 29 i Oct 14 7 2 6 Aug 19 Sep 26 Table 2. Crabgrass counts1 in Kentucky bluegrass treated with com gluten meal in the 1995 Com Gluten Meal Rate 1 2 3 4 5 ITT Material Untreated control Corn gluten meal Corn gluten meal Corn gluten meal Corn gluten meal Rate lb product/1000 ft2 NA 10 fb 10 fb 10 fb 10 20 fb 20 30 fb 10 40 L S D q.05 July 31 August 19 17 5 6 4 9 16 4 4 4 11 10 14 2 3 3 8 NS NS NS NS = means are not significantly different at the 0.05 level. 59 Sept Table 3. Dandelion counts1 in Kentucky bluegrass treated with com gluten meal in the 1995 Com Gluten Meal Rate Weed Control Study. 1 2 3 4 5 Material Untreated control Corn gluten meal Corn gluten meal Corn gluten meal Corn gluten meal Rate lb product/1000 ft2 NA 10 fb 10 fb 10 fb 10 20 fb 20 30 fb 10 40 Jun May 7 37 18 19 17 May 14 32 8 6 6 19 4 7 3 21 9 10 NS NS NS L S D 0 .0 5 1These data represent the number o f dandelion plants per plot. 2 Jun 29 27 7 Jul 31 81 23 11 21 7 10 27 33 Aug 19 58 24 24 26 31 NS 33.5 NS Sep NS 10 58 15 17 18 26 Table 4. Percentage clover cover1 in Kentucky bluegrass treated with com gluten meal in the 1995 Com Gluten Meal Rate Weed Control Study. 1 2 3 4 5 Material Untreated control Corn gluten meal Corn gluten meal Corn gluten meal Corn gluten meal L S D q.05 Rate lb product/1000 f t 2 NA 10 fb 10 fb 10 fb 10 20 fb 20 30 fb 10 40 May 7 65 May 14 53 1 0 2 2 0 40.9 26.5 1 2 2 lrThese figures represent the percentage o f each plot covered by clover. 60 June 2 June 29 57 July 31 60 4 3 Aug 19 58 5 5 Sept 10 1 8 8 0 7 10 8 42 4 5 17 7 NS 40.5 32.1 21.4 NS 22 0 3 5 0 0 1999 Corn Gluten Meal/Urea Crabgrass Control Study - Year 4 - 2002 Nick E. Christians and Lukas Dant This study was initiated in 1999 to determine if the levels of annual grass and broadleaf weed control provided by com gluten meal (CGM) treatments can be explained by the nitrogen response of treated bluegrass and not herbicidal activity of CGM. The study is being conducted at the Iowa State University Research Station north of Ames, IA in an area of ’Parade’ Kentucky bluegrass. The soil in this experimental area is a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 4.2% a pH of 6.75,17 ppm P, and 103 ppm K. The experimental design is a randomized complete block with three replications. Individual experimental plots are 5 x 5 ft with five treatments. Com gluten meal and urea are applied yearly to the same plots at an annual rate of 4 lbs N/1000 ft2 (Table 1). Treatments included split applications of 2 lb N/1000 ft2 and four applications of 1 lb N/1000 ft2. The CGM and urea are applied using cardboard containers as 'shaker dispensers'. The materials are watered-in with the irrigation system. Supplemental irrigation is used to provide adequate moisture to maintain the grass in good growing condition. In 2002, initial applications of all urea and CGM treatments were made on April 26. Sequential applications of 1 lb N/1000 ft2 were made on June 2, July 18, and August 14. The second applications of 2 lb N/1000 ft2 for urea and CGM (Treatment 3 and 5) were made on July 18. Turf quality was monitored from May 9 through October 14 (Table 1). Visual turf quality was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable, and 1 = worst turf quality. Crabgrass data represent the number of plants per individual plot. Crabgrass counts were made on July 31, August 19, and September 10 (Table 2). Broadleaf weed populations were measured by either counting the number of plants or estimating the percentage cover per individual plot. Data for dandelion and clover were taken beginning on May 7 and ending September 10. Dandelion infestations were determined by counting the number of plants per individual plot. Clover populations were estimated by assessing the percentage area of each plot covered by clover. Data were analyzed with the Statistical Analysis System (SAS) and the Analysis of Variance (ANOVA) procedure. 1 2 3 4 5 Material Untreated control Corn gluten meal Corn gluten meal Urea (46-0-0) Urea (46-0-0) Number of applications NA 4 2 4 2 May 9 3.7 4.0 5.3 6.3 5.3 May 14 5.0 6.0 6.3 7.0 6.0 Jun 1 5.3 5.0 5.3 5.7 5.7 Jun 29 1.0 1.3 1.0 1.3 1.7 Aug 19 6.3 7.7 8.3 8.0 7.3 Sep 10 5.3 6.7 7.3 7.3 6.3 Sep 26 4.0 6.3 7.0 6.7 6.0 Oct 14 5.7 6.3 7.7 7.0 6.3 1.4 1.6 NS NS NS NS 0.6 NS LSDoos Visual quality was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable, and 1 = worst turf quality. Initial applications of all treatments were made on April 21. Sequential applications of treatments 2 and 4 were made on July 7, July 27. September 5. The second applications of treatments 3 and 5 were made on July 27. NS = means are not significantly different at the 0.05 level. Table 2. Crabgrass counts1in Kentucky bluegrass treated in the 1999 Com Gluten Meal/Urea Weed Control lbs N Number of Aug Jul Material /1000 ft2 applications 31 19 NA NA 3.7 4.3 1 Untreated control 4 4 2 Corn gluten meal 3.3 7.0 4 2 3.0 4.0 3 Corn gluten meal 4 4 4 Urea (46-0-0) 11.3 17 4 5 Urea (46-0-0) 2 2.7 6.3 NS LSDo.o5 1These values represent the number of crabgrass plants per plot covered. NS = means are not significantly different at the 0.05 level. 61 NS Study. Sep 10 2 2 0 3 1 NS Table 3. Dandelion counts1 in Kentucky bluegrass treated in the 1999 Com Gluten Meal/Urea Weed Control Study. Number of May Jun May Jun Jul Aug Material applications 7 14 1 29 31 19 NA 18.0 1 Untreated control 10.7 7.3 11.3 21.0 3.7 4 2 Corn gluten meal 15.3 8.3 8.7 20.0 3.3 20.7 3 Corn gluten meal 2 12.7 6.7 6.3 13.3 3.0 13.3 4 4 Urea (46-0-0) 11.3 7.0 6.0 12.3 11.3 12.3 2 5 Urea (46-0-0) 17.0 13.3 7.7 17.3 2.7 17.3 NS LSDoos 1These values represent the number of dandelion plants per plot. NS = means are not significantly different at the 0.05 level. 4.8 NS 8.9 10.8 NS Table 4. Percentage clover cover in Kentucky bluegrass treated in the 1999 Com Gluten Meal/Urea Weed Control Number of May May Jun Jun Jul Aug Material applications 7 14 1 29 31 19 NA 1 Untreated control 36.7 26.7 21.7 31.7 28.7 26.7 4 2 Corn gluten meal 23.7 21.7 20.0 21.7 16.0 9.0 2 3 Corn gluten meal 18.7 9.0 16.7 18.3 11.7 5.7 4 4 Urea (46-0-0) 10.0 4.0 8.3 10.0 5.7 6.7 2 5 Urea (46-0-0) 10.3 8.3 0.0 27.0 8.7 6.0 LSDoos 'These values represent the area per plot covered by clover. NS = means are not significantly different at the 0.05 level. NS NS NS NS NS NS Sep 10 19 17 13 13 18 NS Study. Sep 10 36.7 25 19 9.3 12.7 NS Wetting Agents and Hydrophobicity of Golf Course Fairways D.D. Minner andF .V alverde Purpose: To determine the effect of experimental wetting agents on soil hydrophobicity. Methods: This study was conducted in the summer of 2002 on the second fairway at River Bend Golf Course, Story City, IA. The study area had a segregated mixture of 50% Kentucky bluegrass and 50% perennial ryegrass that was mowed at 0.75 inches and was growing on a Nicollet (fine-loamy, mixed mesic Aquic Hapludoll) soil. Treatments were applied using a carbon dioxide backpack sprayer equiped with Teejet® XR8002 flat fan nozzles at 30 psi. Each treatment was mixed into 400 ml water and evenly applied onto a 25 sq.ft, plot. This translates to an application volume of 4 gal/1000 sq.ft. Treatments were applied 5 days prior to each sampling date. The study area was sampled for hydrophobicity on August 24 and September 1, 8,16, and 22,2002. Soil hydrophobicity was assessed following the procedure described by Kostka (2000). Two cores of soil from each plot were taken using zero contamination tubes (Clements Associates, Newton Iowa, USA). Cores were removed from tubes and air dried for 2 weeks at 23 °C. Six droplets (40 pi) of distilled water were applied to each soil core at 6 depths. Starting at depth of 0.5 cm until 6.5 cm, with 1 cm increments. Time was recorded until no free standing water was observed. Treatments were arranged in a randomized complete block design with 7 treatments and 4 replications. All data were analyzed using the Statistical Analysis System (SAS, Version 6.12) and the Analysis of Variance Procedure (ANOVA). Results: Turf quality was evaluated on a scale of 9-1,9 = best, 6 = lowest acceptable, and 1 = worst quality. Dry spot was evaluated on a percent of the area showing dry spots. The fairway study area at River Bend Golf Course is normally irrigated during the summer. City water restrictions did not allow for summer irrigation in 2002. The only water applied to the study area came from rainfall or a 0.13-inch hand-watering-in of the entire study area after each treatment date. A 0.25-inch irrigation was applied on the last sampling date because the lack of soil moisture caused the ground to be too hard for sampling. Rainfall totals for May, June, July, August, and September were 4.12, 1.51, 3.10, 4.14, and 0.89 inches, respectively. First sampling date 8-24-02 Wetting agent treatments had a significant effect on water absorption at the 0 to 2 cm depth. Hydrophobicity was greatest at the surface and decreased deeper in the soil profile. Aqueduct at 4 and 8 oz and ACA at 4 oz provided better soil wetting than the control or ACA 1847. No dry spots were observed on the fairway study area, and turf quality for all plots was 7.5 Second sampling date 9-8-02 Wetting agent treatments showed no significant differences; however, the same trend was observed. Water intake was nearly twice as fast for Aqueduct and ACA 1460 compared to the control and ACA 1847. Treatment rate did not affect hydrophobicity measurements. Third sampling date 9-8-02: No treatment differences or trends were present at this sampling date. No dry spots were observed on the fairway study area and turf quality for all plots was 6.5 Forth sampling date 9-16-02: No treatment differences or trends were present at this sampling date. Fifth sampling date 9-22-02 Wetting agent treatments had a significant affect on water absorption at the 0 and 2 cm depth. Once again, Aqueduct and ACA1460 reduced hydrophobicity more than the control and ACA 1847. Treatment rate did not affect hydrophobicity measurements. No dry spots were observed on the fairway study area and turf quality for all plots was 8.0. Conclusions: Aqueduct and the experimental ACA 1460 reduced hydrophobicity. Treatment rate had no effect on hydrophobicity. There were no visual symptoms of phytotoxicity or dry spot appearance in the study. 63 Reference: Kostka, S.J. 2000. Amelioration of water repellency in highly managed soils and the enhancement of turfgrass performance through the systematic application of surfactants. Journal of Hidrology. 231-232: 359-368 Trt # 1 2 3 4 5 6 7 Treatment Control Aqueduct Aqueduct ACA1847 ACA1847 AC A l 460 AC Al 460 Rate /1000 ft2 4 oz. 8 oz. 2 oz. 4 oz. 4 oz. 8 oz. Rate / m2 1.25 ml 2.5 ml 0.63 ml 1.25 ml 1.25 ml 2.5 ml Rate / plot 2.9 5.8 1.45 2.9 2.9 5.8 Rate / plot + 50% water 5.8 11.6 2.9 5.8 5.8 11.6 First Sampling Date 8/24/02 Absorption time (seconds) 4cm 3cm 5cm 6cm 0.29 0.10 0.00 0.05 0.30 0.20 0.00 0.20 0.12 0.55 0.00 0.00 0.15 0.20 0.05 0.20 0.16 0.05 0.00 0.00 0.10 0.05 0.00 0.10 0.04 0.4463 0.5447 0.4602 0.6400 Trt 0cm 1cm 2cm 1.Control 2. Aqdt 4oz 3. Aqdt 8oz 4. ACA1847 2oz 5.ACA1847 4oz 6.ACA1460 4oz 7.ACA l460 8oz Average 12.75 1.90 3.00 16.55 15.10 3.15 7.70 8.59 5.13 0.80 0.90 4.30 4.45 1.20 2.60 0.30 0.05 0.15 0.70 0.50 0.00 0.35 2.77 0.60 0.20 0.10 1.20 0.80 0.20 0.95 0.58 0.0216 10.0480 0.0487 3.3596 0.0301 0.7227 P LSD (t 0.05) Second Sampling Date 9/1/02 Absorption time (seconds) Trt 0cm 1cm 2cm 3cm 4cm 5cm 6cm l.Control 2. Aqdt 4oz 3. Aqdt 8oz 4. ACA1847 2oz 5.ACA1847 4oz 6.ACA l460 4oz 7.ACA l460 8oz Average 32.30 12.50 14.55 24.74 27.80 23.20 7.35 20.35 10.25 4.60 5.55 7.40 12.20 7.95 5.35 3.35 1.55 3.25 3.50 3.50 5.40 1.80 0.55 1.95 1.65 1.45 1.10 1.35 0.35 7.61 3.19 1.20 1.00 0.75 1.90 0.90 0.80 0.85 0.45 0.95 0.15 0.50 1.60 0.35 0.35 0.30 0.30 0.51 0.25 1.10 2.75 0.90 0.00 0.25 0.40 0.81 P LSD (t 0.05) 0.4808 0.7305 0.6224 0.2968 0.7114 0.0382 1.4515 0.0664 64 Third Sampling Date 9/8/02 Trt 0cm 1cm 2cm l.Control 2. Aqdt 4oz 3. Aqdt 8oz 4. ACA1847 2oz 5.ACA1847 4oz 6.ACA l460 4oz 7.ACA l460 8oz Average 14.30 19.85 16.55 25.40 18.20 25.55 25.50 20.76 5.40 9.25 5.70 7.60 7.70 9.90 9.30 7.84 2.80 2.90 2.90 2.75 2.90 2.65 4.00 P LSD (t 0.05) 0.5770 Absorption time (seconds) 3cm 4cm 5cm 6cm 2.99 1.80 2.40 1.35 1.35 1.90 1.35 1.85 1.71 0.75 1.00 1.20 0.85 0.80 1.90 1.55 1.15 0.95 0.90 1.30 0.50 2.00 0.40 0.60 0.95 0.40 0.25 0.75 0.30 1.35 0.35 0.45 0.55 0.1849 0.9285 0.7539 0.3047 0.7538 0.5836 5cm 6cm 0.00 0.10 0.20 0.00 0.00 0.00 0.00 0.00 0.00 0.05 0.00 0.00 0.00 0.00 Forth Sampling Date 9/16/02 Absorption time (seconds) 3cm 4cm Trt 0cm 1cm 2cm l.Control 2. Aqdt 4oz 3. Aqdt 8oz 4. ACA1847 2oz 5.ACA1847 4oz 6.ACA l460 4oz 7.ACA l460 8oz 3.05 3.50 2.40 2.65 2.80 4.10 2.35 2.98 1.25 1.55 2.30 0.95 2.35 3.25 2.45 0.55 0.50 1.15 0.40 0.90 1.00 0.85 2.01 0.76 0.39 0.08 0.04 0.01 0.8570 0.5389 0.3959 0.0300 0.9217 0.0503 0.2633 0.5622 0.4552 Average P LSD (t 0.05) 0.00 0.05 0.80 0.15 0.70 0.55 0.50 0.00 0.00 0.05 0.00 0.20 0.15 0.15 Fifth Sampling Date 9/22/02 Absorption time (seconds) Trt 0cm 1cm 2cm 3cm 4cm 5cm 6cm l.Control 2. Aqdt 4oz 3. Aqdt 8oz 4. ACA1847 2oz 5.ACA1847 4oz 6.ACA l460 4oz 7.ACA l460 8oz Average 11.05 6.50 3.21 7.25 7.15 2.65 1.65 5.64 3.40 3.35 4.26 3.65 5.20 1.85 0.90 1.35 1.20 1.32 0.85 2.80 0.70 0.60 1.26 0.75 1.15 0.53 0.30 1.15 0.80 0.55 0.50 0.70 0.37 0.55 0.70 0.25 0.50 0.35 0.30 0.00 0.10 0.35 0.10 0.05 0.75 0.51 0.18 0.15 0.00 0.00 0.00 0.15 0.00 0.00 0.04 0.0029 0.0918 0.0006 0.0317 0.3744 0.0810 0.0826 0.8334 0.5447 P LSD (t 0.05) 4.0320 3.23 65 Iowa State University Personnel Affiliated with the Turfgrass Research Program Natalie Canier Graduate Student, M.S. (Minner) Nick Christians, Ph.D. Professor, Turfgrass Science Research and Teaching, Horticulture Dept. Luke Dant Field Research Technician Will Emley Superintendent, Horticulture Research Station Shui-Zhang Fei, Ph.D. Assistant Professor, Turfgrass Science Research (Plant Breeding), Horticulture Dept. Mark Gleason, Ph.D. Professor, Extension Plant Pathologist, Plant Pathology Dept. Mark Helgeson Field Technician, Horticulture Dept. Mark Howieson Graduate Student, Ph.D. (Christians) Jeff Des, Ph.D. Associate Professor, Extension, Nursery Crops/Omamentals, Horticulture Dept. Young K. Joo, Ph.D. Visiting Scientist from Korea Jason Kruse Graduate Student, Ph.D. (Christians and Chaplin - starting Fall 2001) Donald Lewis, Ph.D. Professor, Extension Entomologist, Entomology Dept. Deying Li, Ph.D. Postdoctoral Research Associate (Christians and Minner) David Minner, Ph.D. Associate Professor, Turfgrass Science Research and Extension, Horticulture Dept. David J. Minner Field Research Technician Meghan Minner Field Research Technician Sarah Minner Field Research Technician Hugh O’Donnell Field Research Technician Troy Oster Graduate Student, M.S. (Christians) Ryan Pertle Field Research Technician Rodney St. John Superintendent, Turfgrass Research Station, Horticulture Dept. Joe Stoeffler Field Research Technician Federico Valverde Research Associate, Horticulture Dept. Joel Vint Field Research Technician 66 Companies and Organizations That Made Donations or Supplied Products to the Iowa State University Turfgrass Research Program Special thanks are expressed to Tri-State Turf and Irrigation for providing a Greensmaster 3100 Triplex Greensmower and a Groundsmaster 345 Rotary Mower, to Great American Outdoor for providing a John Deere 2500 Triplex Greensmower, and to Sun Turf and Textron for providing a Cushman Turfgrass Truckster for use at the research area. Aiken Peat Andersons Lawn Tech BASF Becker Underwood Chemical Services Labs D & K Turf Products Dow Agrosciences Gardens Alive G olf Course Superintendents Assoc, o f America Great American Outdoor Heatway Hunter Industries, Inc. Iowa G olf Course Superintendents Assoc. Iowa Professional Lawn Care Assoc. Iowa Sports Turf Managers Assoc. Iowa Turfgrass Institute Jacklin Seed LESCO Incorporated Micro Flo Milorganite Monsanto Company Ossian Inc. PBI/Gordon Corporation Pickseed West Incorporated Profile Products Rainbird Irrigation Company Riverdale Chemical Company The Scotts Company SubAir Sun Turf Equipment Company Syngenta TeeJet Spray Products Terra Chemical Corporation Textron The Toro Company Tri State Turf & Irrigation Co. True Pitch, Inc. Turf-Seed, Inc. United Horticultural Supply United Seeds Inc. United States G olf Assoc. Valent Chemical Weathermatic Corporation Williams Lawn Seed Company 67 . . . and justice for all The Iowa Cooperative Extension Service’s programs and policies are consistent with pertinent federal and state laws and regulations on nondiscrimination. Many materials can be made available in alternative formats for ADA clients. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Stanley R. Johnson, director, Cooperative Extension Service, Iowa State University of Science and Technology, Ames, Iowa.