Disease Alert - Large Patch

According to Lane Tredway, plant pathologist and extension specialist, North Carolina State University, large patch has been observed in several locations. The disease has become active during recent periods of cool, rainy weather.

Large patch is a common disease of warm-season turfgrasses in the fall and spring. The disease becomes active in the fall when soil temperatures dip to 70F, and the disease continues to develop throughout the fall and spring. Centipedegrass and St. Augustinegrass are the most susceptible turf species, while zoysiagrass and Bermudagrass are more resistant.

Symptoms of large patch appear in roughly circular patches that are yellow, tan, or straw-brown in color. The patches are initially 2 to 3 feet in diameter, but can expand in size rapidly up to 10 feet or more in diameter. When the disease is actively developing, the outer edges of the patches are often red, orange, or reddish-brown. Close examination of individual plants reveals the presence of reddish-brown, oval-shaped lesions on the leaf sheaths of affected plants.

Large patch is favored by excessive nitrogen, poor soil drainage, over-irrigation, and excessive thatch accumulations. Correcting these cultural problems will help to reduce the severity of large patch development.