In April through October the grass wilts, turns yellowish brown, dries out, and dies in sunny areas and along sidewalks and driveways. Chinch bugs feed on many kinds of lawn grasses, but St. Augustinegrass and zoysiagrass are favorites. Both the adults and the nymphs suck the juices out of the blades. At the same time, they inject a poison that causes the blades to turn brown and die. Heavy infestations may completely kill the lawn. These sun- and heat-loving insects seldom attack shady lawns.
To check for chinch bugs, select a sunny spot on the edge of an affected area where yellow grass borders healthy green grass. Cut out both ends of a tin can. Push one end of the can 2 to 3 inches into the soil. Keep it filled with water for 10 minutes. Black to brown insects with white wings float to the surface in 5 to 10 minutes. Pink to brick-red nymphs with a white stripe around the body may also be numerous.