Chinch Bugs Chinch bugs are the premier pest on St. Augustinegrass lawns and will attack other grasses except those in the coldest climates.  Black, winged, and 1/5-inch long, they live and lay eggs in the thatch layer at the root line. Most damaging are the tiny red nymphs, which thrive on sap sucked from grass stems. The adult chinch bug is the scourge of southern grasses. The chinch bug nymph…