The southern chinch bug is a pest of St. Augustine grass, particularly during periods of hot, dry weather as is common in July and August. Winter is spent in the adult stage except where weather permits year-round reproduction.
Adults are black, about 3/16-inch long, and have either fully developed or very short wings which, when held in place across the back (abdomen), appear bone white.
The bugs have a gradual life cycle, and during the warmer months nymphs and adults often are often found together. Nymphs range from 1/16-inch to 3/16-inch long. Smaller, early instar nymphs are orange-pink and have whitish bands on their abdomens just behind the thorax. As nymphs grow they become progressively darker and develop wing pads.
Chinch bug infestations often are spotty and may be restricted to certain lawns or parts of lawns. Nymphal and adult stages have sucking mouthparts with which they draw sap from the grass stems (stolons) and inject saliva. When chinch bug numbers are large, and particularly during extended dry periods, severely damaged grass turns yellow and dies. Because of the uneven (clumped) distribution of the insects in the grass, damage is usually seen as irregular patches of dead or dying grass; as damage progresses, these patches grow and coalesce until the whole lawn may be lost.
Treatment is usually considered when damage symptoms appear and chinch bugs are detected at the edge of the damaged area using the flotation or vacuum method.