Characterization and Pathogenicity of Species of Rhizoctonia Associated with Centipedegrass and St. Augustinegrass in South Carolina. R. A. Haygood, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29630. S. B. Martin, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29630. Plant Dis. 74:510-514. Accepted for publication 19 December 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0510.

Rhizoctonia solani, R. oryzae, R. zeae, and binucleate Rhizoctonia spp. were recovered from basal sheaths of centipedegrass (Eremochloa ophiuroides) and St. Augustinegrass (Stenotaphrum secundatum) submitted to the Clemson University Plant Problem Clinic. All 35 isolates of R. solani tested for anastomosis were assigned to anastomosis group 2 type 2 (AG-2-2). R. solani, R. oryzae, and R. zeae induced sheath rot of centipedegrass and St. Augustinegrass. R. zeae and R. oryzae also induced foliar lesions on both grasses. Binucleate Rhizoctonia spp. were isolated more commonly than multinucleate species from centipedegrass, but isolates tested were determined to be either nonpathogenic or weak pathogens on both centipedegrass and St. Augustinegrass.