77-15 Multi-State Evaluation of Dollar Spot Susceptibility in Creeping Bentgrass.

Poster Number 246

See more from this Division: C05 Turfgrass Science
See more from this Session: Turfgrass Pest Management
Monday, November 1, 2010
Long Beach Convention Center, Exhibit Hall BC, Lower Level
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Qi Zhang1, Christopher Blume2, Jeffery Bryan3, Nick Christians2, Kenneth Diesburg4, Kevin Frank3, Jack Fry5, David Gardner6, Megan Kennelly7, Dennis Martin8, Keith Rincker9, Derek Settle10, Douglas Soldat11, John Stier12 and Cole Thompson5, (1)PO Box 6050, North Dakota State University, Fargo, ND
(2)Iowa State University, Ames, IA
(3)Michigan State University, East Lansing, MI
(4)Southern Illinois University, Carbondale, IL
(5)Kansas State University, Manhattan, KS
(6)2001 Fyffe Ct., The Ohio State University, Columbus, OH
(7)Plant Pathology, Kansas State University, Manhattan, KS
(8)Oklahoma State University, Stillwater, OK
(9)Chicago District Golf Association, Cerro Gordo, IL
(10)Chicago District Golf Assoc., Lemont, IL
(11)University of Wisconsin-Madison, Madison, WI
(12)University of Wisconsin, Madison, WI
Dollar spot (Sclerotinia homoeocarpa) is a common disease on creeping bentgrass (Agrostis stolonifera) putting greens and fairways, and is typically treated using calendar-based preventative fungicides. This may lead to applications of more fungicide than necessary, causing environmental and economic concerns. The objectives of this research were to: 1) evaluate dollar spot susceptibility in commonly used commercial creeping bentgrass cultivars; 2) study environmental influences on dollar spot occurrence and severity; and 3) evaluate the suitability of a threshold-based fungicide application schedule for dollar spot control on a disease-resistant cultivar. The experiment was initiated in 2008 in nine states as a split-block design with three replicates. The whole-plot treatments were bentgrass cultivars and the sub-block treatments were two fungicide application regimes [ (no fungicide vs. a combination of boscalid and chlorothalonil applied when dollar spot was > 5% or 10% under putting green and fairway condition, respectively, in two of the three replicates in ‘Declaration’ (a S. homoeocarpa resistant cultivar)]. Dollar spot was observed in KS, IA, MI, WI, and IL in 2009. However, fungicide treatments were applied only in KS and IA due to the low disease pressure in other locations. The preliminary results showed that turfgrass quality and dollar spot occurrence and severity were affected by environmental conditions. ‘Crenshaw’ and ‘Declaration’ were the least and the most tolerant to dollar spot, respectively. Fungicide applications reduced dollar spot up to 36%. Variations in bentgrass quality were mostly due to the differences of disease sensitivity during summer.
See more from this Division: C05 Turfgrass Science
See more from this Session: Turfgrass Pest Management