Identity and Pathogenicity of Two Marasmius Species from the Sterile White Basidiomycete Complex. Richard E. Baird, Department of Plant Pathology, Purdue University, Southwest Research Extension Center, Vincennes, IN 47591. Jeffrey P. Wilson, and Donald R. Sumner. USDA-ARS, Forage and Turf Research Unit, and Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton 31793. Plant Dis. 76:244-247. Accepted for publication 8 September 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0244.

Three isolates with white mycelium, rhizomorphic strands, clamp connections, and dolipore septa belonging to the plant-pathogenic group known as the sterile white basidiomycetes (SWB) were isolated from bermudagrass (Cynodon dactylon) and cultured in flasks on living sweet corn (Zea mays) and snap bean (Phaseolus vulgaris) plants grown in vitro. Sporophores of Marasmius graminum and M. rotula were formed in flasks containing the isolate designated as SWB 1. Reisolations from the pilei of both Marasmius spp. were identical to the original SWB 1, which indicates that either this culture was contaminated with both species or the isolate has two teleomorphic states. Pathogenicity tests with the three original isolates and reisolations from the two sporophores were conducted with sweet corn, snap bean, pearl millet (Pennisetum glaucum), pigeon pea (Cajanus cajan), sorghum (Sorghum vulgare), and rye (Secale cereale). The five isolates were slightly virulent to all six crops in the greenhouse, but results from the field were more ambiguous and showed fewer significant differences compared with the control. SWB fungi were reisolated from all six crops in the greenhouse and field experiments.