Rhizoctonia Foliar Blight of Cabbage in New York State. G. S. Abawi, Associate Professor, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. S. B. Martin, Postdoctoral Research Associate, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Plant Dis. 69:158-161. Accepted for publication 8 August 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-158.

Late in the 1983 season, small, irregular, brown to black lesions developed on cabbage heads grown in western New York. These symptoms were observed initially on cabbage cultivars Superdane and Greenwinter, which are grown primarily for fresh market. Rhizoctonia solani anastomosis group 1 was isolated from these lesions. Cultures of these isolates were dark brown, produced numerous small sclerotia, and had an optimum temperature of about 28 C for mycelial growth. Growth rates at 28 C averaged 2.1 mm/hr. Attempts to induce the sexual state of this fungus (Thanatephorus cucumeris) under laboratory conditions were unsuccessful. Inoculation of intact cabbage heads or detached leaf segments with a mycelial suspension, sclerotial masses, artificially infested soil, or 3-day-old potato-dextrose mycelial agar disks of R. solani produced lesions similar to those observed in the field. Similar isolates of R. solani were recovered from inoculated plants. Cabbage foliar blight isolates of R. solani were also pathogenic to snap bean hypocotyls and leaves under high moisture conditions.