This helps the poison soak into the thick mat of grass. Apply poison with a power sprayer, 3-gallon compressed air sprayer, sprinkling can, or spray attachment for garden hose. Sprinkle lawn with water again after you apply insecticide. Where chinch bug infestations are heavy, re-treat the lawn in two weeks to kill newly hatched bugs. The principal caterpillars that can damage lawn grasses are the sod webworm and the fall armyworm.
Sod webworms feed at night and curl up on or near the top of the soil during the day.
This makes them hard to find. They chew notches in the grass blades and eat them back unevenly. Part the grass and check for small, green worms curled up on the soil. You will also find small, green pellets of worm excrement. You can find them feeding on the grass during the day.