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Dollar Spot and Brown Patch Fungicide Management Strategies in Four Creeping Bentgrass Cultivars
Author(s) -
Settle Derek,
Fry Jack,
Tisserat Ned
Publication year - 2001
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2001.4141190x
Subject(s) - fungicide , biology , cultivar , rhizoctonia solani , chlorothalonil , agronomy , horticulture
New creeping bentgrass ( Agrostis palustris Huds.) cultivars should be thoroughly evaluated for disease resistance and fungicide application strategies for inclusion in integrated pest management plans. Our objectives were to evaluate dollar spot ( Sclerotinia homoeocarpa F.T. Bennett) and brown patch ( Rhizoctonia solani Kühn) severity, and turf quality of ‘L‐93’, ‘Penncross’, ‘Providence’, and ‘Crenshaw’ creeping bentgrass managed using preventive, curative, and weather model‐based fungicide application strategies. This field study was conducted on a sand‐based putting green in Manhattan, KS, from 1997 through 1999. Nonfungicide‐treated L‐93 exhibited greatest resistance to dollar spot; Penncross and Providence were intermediate; and Crenshaw was most susceptible. Crenshaw exhibited greater brown patch susceptibility than other cultivars in 1998, but was similar to L‐93 in 1999. Greater flexibility in imposing a disease control strategy was afforded by using a disease‐resistant (i.e., L‐93), rather than a disease‐susceptible (i.e., Crenshaw) cultivar. Dollar spot was controlled in L‐93 using preventive fungicide applications on 14‐ or 28‐d intervals, preventive low‐rate applications of chlorothalonil (tetrachloroisophthalonitrile, 3.5 kg a.i. ha −1 ) every 7 d, or a curative fungicide application when an increase in the disease was observed. In Crenshaw, only the 14‐d preventive fungicide regime effectively controlled dollar spot. Considering all cultivars across the 3‐yr period, fewer fungicide applications were made using a curative ( n = 11–17) than a preventive ( n = 30) strategy. The curative strategy was effective when dollar spot, but not when brown patch was the primary disease.