Snow molds of turfgrasses in Saskatchewan1
- J. D. Smith
A lack of precise diagnostic evidence on the causes and distribution of snow molds in Saskatchewan has obscured the definition of turfgrass breeding and plant protection research problems. Surveys and taxonomie studies conducted since 1969 have shown that psychrophilic plant pathogens cause major turfgrass damage. Pathogen distribution in Saskatchewan and other parts of Western Canada has perturbed the general concept of a broadly north/south distribution of Sclerotinia borealis Bub. & Vleug., Typhula spp., the unidentified nonsclerotial low-temperature basidiomycete (LTB), and Fusarium nivale (Fr.) Ces. In many Saskatchewan locations more than one pathogen was prominent, and in some places several were found. F. nivale and S. borealis, which are widespread causes of severe snow mold, set new records for Saskatchewan in 1971. A Typhula sp., similar to T. ishikariensis Imai was found in 1972 and 1973 and other Typhula spp., but not T. incarnata Lasch ex Fr., were frequent on diseased amenity and sports turf. A pathogenic, unidentified, sclerotial, psychrophilic basidiomycete (SLTB), not a Typhula sp., has often been found on patches assumed to be caused by the LTB. A psychrophilic, apparently nonpathogenic fungus with orange-colored, rindless sclerotia (ORS) of widespread distribution showed antagonism in culture at low temperatures to most common snow mold fungi. Where one late fall fungicide application was made to turf artificially or naturally infected with LTB. S. borealis or F. nivale, quintozene (pentachlornitrobenzene) or chloroneb (1,4,dichloro-2,5,dimethoxybenzene) were generally effective in control. However, benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate], thiophanatemethyl [1,2-bis(3-methoxycarbonyl-2-thioureido)benzene], chlorothalonil (tetrachloroisophthalonitrile), and an oxathiin derivative were worthy of further testing as alternatives to mercurial fungicides. Additional index words: Western Canada, Snow mold prevalence and distribution, Nonsclerotial psychrophilic basidiomycete, Sclerotial psychrophilic basidiomycete, Fusarium nivale, Sclerotinia borealis, Typhula spp., Orange rindless sclerotia, Interaction in snow mold complexes, Chloroneb, Quintozene.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 1974. . Copyright 1974 by the American Society of Agronomy, Inc. and the Crop Science Society of America, Inc., 5585 Guilford Rd., Madison, WI 53711 USA