Red leaf spot is a disease occuring frequently on Creeping Bentgrass during warm and wet weather in the spring, summer, or fall.
Symptoms of red leaf spot appear in spots or irregular patches that are red or reddish-brown. On individual plants, symptoms appear as small, red or reddish-brown leaf spots with a tan center. As the lesions expand and coalesce, the turfgrass leaves become blighted and collapse to the ground. Red leaf spot is one of several that survive in the thatch layer during periods unfavorable for disease development.
Control can be enhanced by reducing periods of leaf wetness with deep and infrequent irrigation while wetting the entire root zone then re-applying when the root zone becomes dry. Do not irrigate just before or after sunrise and remove dew in the morning to shorten leaf wetness periods. Remove unwanted vegetation that impedes air movement and prune trees to increase light penetration. Regular aerification and topdressing is needed to reduce thatch accumulations and minimize pathogen survival.