Prevalence of Pythium Species Associated with Cottony-Blighted and Healthy Turfgrasses in Ohio. J. L. Saladini, Former Graduate Research Associate, Department of Plant Pathology, Ohio State University, Columbus 43210, and Ohio Agricultural Research and Development Center, Wooster 44691. A. F. Schmitthenner and P. O. Larsen, Professors, Department of Plant Pathology, Ohio State University, Columbus 43210, and Ohio Agricultural Research and Development Center, Wooster 44691. Plant Dis. 67:517-519. Accepted for publication 24 September 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-517.

In turfgrass plants with Pythium (cottony) blight, Pythium aphanidermatum, P. graminicola, and P. torulosum were isolated most frequently, with P. aphanidermatum predominating. P. torulosum, P. rostratum, P. catenulatum, and P. vanterpoolii were the predominant Pythium spp. isolated from healthy turf. P. torulosum, P. vanterpoolii, P. aphanidermatum, P. rostratum, P. irregulare, and P. oligantum were the predominant Pythium spp. from turfgrass soil. Other Pythium spp. were occasionally isolated from the three habitats. P. ultimum, a commonly reported turf pathogen and soil species, was not isolated. P. aphanidermatum and P. graminicola were obtained from cottony-blighted shoot tissues after incubation of plants at 30–32 C and 98–100% relative humidity. We have concluded that P. aphanidermatum, P. graminicola, and P. torulosum are most commonly associated with cottony-blighted turf in Ohio.

Keyword(s): Pythium blight, turfgrass disease.