Diseases and disorders are a common occurrence in lawns and are caused either by pathogenic infections or poor cultural maintenance. Dead areas on grass are a likely result of a fungal infection. Diagnosing the problem is the first step toward effective management.
Dollar spot is a fungal disease of turf caused by Moellerodiscus sp., Sclerotinia homeocarpa, and Lanzia sp. fungi. A number of grass species are likely hosts including bermudagrass, fescues, Kentucky annual bluegrasses and bentgrass.
The disease starts with the appearance of 1- to 5-inch diameter, circular dead spots on grass. With disease progression, the spots get larger and more irregular in shape. Initially water-soaked grass blades take on a brown look and often have red bands running across the blades. Cobweb-like fine white threads are visible on grass in the morning.
Avoid overwatering lawns and fertilize with adequate nitrogen fertilizer. Top dress with compost to help prevent fungal growth. Mow grass at increased height. Chemical control strategies include the use of myclobutanil, iprodione or thiophanate-methyl fungicides.