Evaluation of Bentgrass Varieties for Fairways Given Reduced Fungicide Input Researchers: Chicago District Golf ssoc. Derek Settle, Tim Sibicky, Nick DeVries with 11 Midwest Regional University Collaborators (NCER) Objective: Determine the performance of creeping bentgrass cultivars under reduced fungicide inputs for dollar spot on fairways. Collaborating NCER Investigators: Qi Zhang, North Dakota State Univ.; Ken Diesburg, Southern Illinois Univ.; John Stier, Univ. of Wisconsin; Brian Horgan, University of Minnesota; David Gardner, The Ohio State Univ.; Dennis Martin, Oklahoma State Univ.; Terrance Riordan, Univ. of Nebraska; Kevin Frank, Michigan State Univ.; Jack Fry, Kansas State Univ.; Nick Christians, Iowa State Univ.; Brad Fresenburg, Univ of Missouri. Background: Creeping bentgrass (grostis stolonifera) is extensively used on golf course fairways throughout the mid to northern United States. It is typical for turfgrass variety trials to control all pests a beauty contest. Currently, there is limited available research in cultivar testing for reduced fungicide input programs. Today, many golf course superintendents are looking to cut costs and reduce inputs to fairways, their largest acreages of highly managed turf. The CDG is collaborating with North Central Regional scientists from 11 universities who also are conducting this national bentgrass study to benefit golf courses in as many states. Materials and Methods: Twenty four varieties of creeping bentgrass and one colonial bentgrass were arranged in a randomized split block design with 3 replications. Bentgrasses were seeded in October, 2008 and again in May, 2009 due to winter injury. Plots are 5 ft. by 10 ft., maintained at 0.525 inch, and irrigated as needed. Whole plots are bentgrass varieties and split plots are curative fungicide for dollar spot (Sclerotinia homoeoecarpa). Curatively Daconil Ultrex 3.2 oz. + Emerald 0.18 oz. is applied to all varieties when the resistant cultivar Declaration reaches 5% damage. On ugust 2, 2010, first curative application was applied. Results: Dollar spot, Visual quality Dollar spot in 2009. First dollar spot incidence occurred Sep, 2009. Most susceptible bentgrass varieties included; Imperial, Crenshaw, Century, and Penn 4. Most resistant (< 5%) bentgrass varieties included; Pennlinks II, lpha, Crystal Bluelinks, L 93, Memorial, Declaration, as well as lister a colonial bentgrass. (Fig. 1)
Visual Quality (curative fungicide). Dollar spot resistant bentgrass varieties rated best 21 days after 2 curative treatments. Best visual quality = Kingpin, Pennlinks II, SR1150, CY 2, Declaration, Shark, OO7, Memorial. Unacceptable quality = Crystal Bluelinks, Bengal, Independence and Century. (Fig. 2) Dollar Spot (without curative). ll bentgrass varieties were unacceptable visually when untreated, with up to 60 80% dollar spot damage on most susceptible; Southshore, Century, SRP1BLTR, Independence, Crenshaw, Penn 4, Xtreme, and Bengal. The least injured, Memorial at 5%, may have benefited from additional irrigation. (Fig. 3) Table 1. Commercial bentgrass varieties tested for low input fairway use in Lemont, IL. Entry #, variety name Commercial source Entry #, variety name Commercial source 1. L 93 Jacklin Seed 14. Pennlinks II Tee 2 Green 2. T 1 Jacklin Seed 15. Penn 1 Tee 2 Green 3. lpha Jacklin Seed 16. Penn G 6 Tee 2 Green 4. Putter Jacklin Seed 17. OO7 Seed Research of 5. Southshore Jacklin Seed 18. MacKenzie Seed Research of 6. Kingpin ProSeeds 19. Tyee Seed Research of 7. Crenshaw ProSeeds 20. SR 1150 Seed Research of 8. Imperial ProSeeds 21. Memorial Scotts 9. Century ProSeeds 22. Independence Lebanon 10. Penncross Tee 2 Green 23. Declaration Lebanon 11. Penn 4 Tee 2 Green 24. LS 44 Links Seed 12. Crystal Bluelinks Tee 2 Green 25. Bengal Barenbrug US 13. lister (colonial) Tee 2 Green
Bentgrass Fairway Variety Trial: Dollar spot First injury by disease (29 Sep, 2009) Dollar spot damage (%) 35 30 25 20 15 10 5 0 a ab abcd abcde bcdef bcdef bcdef bcdef cdef def def def def Figure 1. First dollar spot incidence occurred Sep, 2009. Most susceptible bentgrass varieties included; Imperial, Crenshaw, Century, and Penn 4. Most resistant (< 5%) bentgrass varieties included; Pennlinks II, lpha, Crystal Bluelinks, L 93, Memorial, Declaration, as well as lister a colonial bentgrass. NCER trial at Sunshine Course, Lemont, IL in 2009.
Visual quality 1 9 (6 = acceptable) 9 8 7 6 5 4 Bentgrass Fairway Variety Trial: Visual Quality (23 ug) With Curative Fungicide (2 ug) B B BC BC BC BCD BCD BCD BCD BCD BCD E Unacceptable E E E E CDE CDE DE Kingpin Plinks2 SR1150 CY2 Declarat shark 007 Memorial xtreme7 L93 Putter penncros MacKenzi Tyee LS44 SRP1RH93 lpha lister xtreme SRP1BLTR T1 Southsho Imperial 4 Crystalb Bengal Crenshaw Independ Century E Figure 2. Dollar spot resistant varieties rated best 21 days after 2 curative treatments. NCER trial at Sunshine Course, Lemont, IL in 2010.
S. homoeocarpa Infection Centers (%) 90 80 70 60 50 40 30 20 10 0 Bentgrass Fairway Variety Trial: Dollar Spot (23 ug) Without Curative Fungicide (2 ug) B BC BC BC BCD F F F F G G G G FG FG DEFGH DEFGH FGH FGH Southsho Century SRP1BLTR Independ Crenshaw 4 xtreme Bengal Imperial Tyee T1 Putter shark SRP1RH93 lpha Plinks2 CY2 xtreme7 L93 SR1150 MacKenzi Declarat LS44 penncros Kingpin lister 007 Crystalb Memorial GH H Figure 3. Without curative treatment all bentgrass varieties were unacceptable visually with most susceptible varieties having 70 80% dollar spot damage. NCER trial at Sunshine Course, Lemont, IL in 2010.