New Jersey Sod Webworms
If lots of sod webworm moths are observed in the evening, watch for damage in about 10 to 14 days. This is when their eggs begin to hatch into caterpillars.
These caterpillars chew off the grass blades close to the soil surface leaving brown stubble as damage. Early August is typically when we see the heaviest damage, although sometimes damage is also heavy in June. Insecticides should be applied to the surface of damaged areas.