This disease occurs during the summer when night temperatures are above 68° F, high day temperatures and high relative humidity.

Symptoms
Brown patch causes a leaf spotting that results in circular brown patches 6 inches to 2 feet and thinned turf. Leaf spots are often irregular and have a thin reddish-brown border. Small patches can coalesce to blight large areas quickly when weather conditions for the disease are ideal. All turfgrass are affected, especially tall fescue and ryegrass. Mature turf is rarely killed. One-year-old stands of tall fescue under severe conditions can be killed