Rhizoctonia solani AG-2-2 was consistently associated with a large patch disease of zoysiagrass in Kansas, Missouri, and Tennessee. In field inoculation tests, patch symptoms developed during both spring and fall as the turfgrass was entering or breaking winter dormancy. The fungus infected and colonized leaf sheaths, but not stolons or roots, at 10-30 C, with optimal infection at 20-25 C. Rhizoctonia large patch development was suppressed in summer by thatch temperatures exceeding 30 C. Ophiosphaerella herpotricha was isolated infrequently from diseased zoysiagrass but did cause extensive root discoloration and weight loss in the greenhouse and circular dead patches 1 yr after field inoculations.