Sod webworms are the larvae of lawn moths, which hide in the day and fly in the evening and at night. When disturbed during daylight hours, the grayish white to tan moths make brief, erratic flight 1 to 2 feet above the ground. They don’t feed on lawns, but their slender, inch-long offspring chew on grass and as the name ”webworm” implies, spin silken tunnels in lawn thatch. Webworms are brown, gray, or green, with dark spots and long, stiff hairs.