College-wide Navigational Links | Go to Local Content
Main Content |

Entomology: Landscape Pest Management: Insect ID: Turf

Sod Webworms

sod webworm caterpillar

sod webworm

Identification

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 light green 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. Sod webworms are found throughout Georgia.

Life Cycle and Biology

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. Two to three generations occur each year. Sod webworms feed only at night.

Damage

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, especially under drought conditions. A heavy infestation can destroy a lawn in only a few days. Damage tends to become visible in mid to late summer and in highly maintained lawns. Sod webworms are partial to newly established lawns. Favored turf types are bermuda, centipede, bahia, zoysia, and St. Augustine grasses.

Control Strategies

Sod webworm populations (and those of other soil-inhabiting insects) can be monitored using the "irritation technique". One ounce of lemon dish detergent is mixed with one gallon of water and the solution is poured over a one square yard area where an infestation is suspected. The detergent irritates the insects, causing them to come to the surface quickly. Damage thresholds vary in different areas. A rough guide is 15 or more larvae per square yard. Insecticide application should be timed for treatment two weeks after peak moth activity and should be made during early evening hours when caterpillars begin feeding.