Evaluation of Bentgrass Varieties for Fairways Given Reduced Fungicide Input Researchers: Chicago District Golf Assoc. ‐ Derek Settle, Tim Sibicky, Nick DeVries with 11 Midwest Regional University Collaborators (NCERA) Objective: Determine the performance of creeping bentgrass cultivars under reduced fungicide inputs for dollar spot on fairways. Collaborating NCERA 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 (Agrostis 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 CDGA 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 August 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 A‐4. Most resistant (< 5%) bentgrass varieties included; Pennlinks II, Alpha, Crystal Bluelinks, L‐93, Memorial, Declaration, as well as Alister a colonial bentgrass. (Fig. 1) •
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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). All bentgrass varieties were unacceptable visually when untreated, with up to 60‐80% dollar spot damage on most susceptible; Southshore, Century, SRP1BLTR, Independence, Crenshaw, Penn A4, 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 A‐1 Tee‐2‐Green 3. Alpha Jacklin Seed 16. Penn G‐6 Tee‐2‐Green 4. Putter Jacklin Seed 17. OO7 5. Southshore Jacklin Seed 18. MacKenzie 6. Kingpin ProSeeds 19. Tyee 7. Crenshaw ProSeeds 20. SR 1150 8. Imperial ProSeeds 21. Memorial Seed Research of Oregon Seed Research of Oregon Seed Research of Oregon Seed Research of Oregon Scotts 9. Century ProSeeds 22. Independence Lebanon 10. Penncross Tee‐2‐Green 23. Declaration Lebanon 11. Penn A‐4 Tee‐2‐Green 24. LS‐44 Links Seed 12. Crystal Bluelinks Tee‐2‐Green 25. Bengal 13. Alister (colonial) Tee‐2‐Green Barenbrug USA Bentgrass Fairway Variety Trial: Dollar spot First injury by disease (29 Sep, 2009)
Dollar spot damage (%)
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Figure 1. First dollar spot incidence occurred Sep, 2009. Most susceptible bentgrass varieties included; Imperial, Crenshaw, Century, and Penn A‐4. Most resistant (< 5%) bentgrass varieties included; Pennlinks II, Alpha, Crystal Bluelinks, L‐93, Memorial, Declaration, as well as Alister a colonial bentgrass. NCERA trial at Sunshine Course, Lemont, IL in 2009. Kingpin
Plinks2
SR1150
CY2
Declarat
shark
007
Memorial
xtreme7
L93
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penncros
MacKenzi
Tyee
LS44
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Alpha
Alister
xtreme
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Imperial
A4
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Bengal
Crenshaw
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Century
Visual quality 1‐9 (6 = acceptable)
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Bentgrass Fairway Variety Trial: Visual Quality (23 Aug)
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With Curative Fungicide (2 Aug)
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Figure 2. Dollar spot resistant varieties rated best 21 days after 2 curative treatments. NCERA trial at Sunshine Course, Lemont, IL in 2010. 70
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Without Curative Fungicide (2 Aug)
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Century
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Memorial
S. homoeocarpa Infection Centers (%)
Bentgrass Fairway Variety Trial: Dollar Spot (23 Aug)
Figure 3. Without curative treatment all bentgrass varieties were unacceptable visually with most susceptible varieties having 70‐80% dollar spot damage. NCERA trial at Sunshine Course, Lemont, IL in 2010.