The disease usually develops on lawns during periods of wet, overcast weather in late spring or fall. In humid coastal areas, brown patch is usually found from late fall through early spring on St. Augustinegrass and centipedegrass lawns during extended periods of mild, cloudy, wet weather. The foliage of high-cut St. Augustinegrass or centipedegrass turf often wilts and collapses, giving the blighted patches a sunken appearance. Damaged turf usually recovers when conditions no longer favor the spread of disease. Regrowth of the turf may start in the center of the blighted area, forming a ring or frogeye pattern.
Weeds frequently invade turf damaged by brown patch.
Damage to individual grass plants is usually confined to the foliage. Leaves and leaf sheaths attacked by the brown patch fungus, Rhizoctonia solani, first become water-soaked, then wilt, and finally turn brown. If the crowns of individual plants or stolons are invaded, large areas of a lawn may be killed. Control Measures Nitrogen fertility has a significant impact on brown patch development. High nitrogen levels promote the growth of soft, succulent leaves that are susceptible to attack by the brown patch fungus.