Sod webworms are caterpillars of small brown to dull gray moths. Webworms grow to a length of nearly 3/4 inch and vary in color from pinkish white to yellowish brown with a light to dark brown or black head. They are covered with fine hairs. The moths have a wingspan of about 3/4 inch. They fold their wings closely about their bodies when at rest and have a prominent forward projection on the head.

Moths hide in shrubbery or other sheltered spots during the day. They fly over the grass in early evening. The female scatters eggs over the lawns as she flies. Sod webworms feed only at night.

Damaged grass blades appear notched on sides and are chewed raggedly. Irregular brown spots are the first signs of damage. Large areas of grass may be damaged severely. A heavy infestation can destroy a lawn in only a few days. Insecticide application should be timed for treatment during early evening hours when caterpillars begin feeding on the surface of the turf.