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Ecology and Epidemiology

Horizontal Distribution and Characterization of Rhizoctonia spp. in Tall Fescue Turf. S. B. Martin, Graduate research assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650, Present address of senior author: New York State Agricultural Experiment Station, Geneva 14456; C. L. Campbell(2), and L. T. Lucas(3). (2)(3)Assistant professor, and professor, respectively, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Phytopathology 73:1064-1068. Accepted for publication 9 February 1983. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-1064.

A 12-yr-old stand of tall fescue (Festuca arundinacea) turf with a history of brown patch (induced by Rhizoctonia solani) was divided into 225 contiguous quadrats (0.37 m² each) and the soil sampled for propagules of Rhizoctonia in June 1980 and 1981 by direct assay of soil organic debris. Propagule number frequency distributions were described by the negative binomial frequency distribution in both years, indicating a horizontal clumping of propagules. Fifty-three isolates in 1980 and 54 isolates in 1981 were recovered and identified as Rhizoctonia solani, R. zeae, or binucleate Rhizoctonialike fungi. R. solani was less frequently recovered (9% of the total in 1980 and 1981) than R. zeae (45.3% in 1980 and 48.2% in 1981) or binucleate Rhizoctonialike fungus (39.6% in 1980 and 42.6% in 1981).