Common Name: Sod webworm
Scientific Name: Crambus : spp
Status: A serious pest of turfgrass and other plants
Damaging Stage: Caterpillar

Biology: Adults are buff-colored, about �-inch long with snout-like projections extending forward from the head. At rest, a webworm folds its wings around the body, giving it a cigar-shaped appearance. A larva is gray to tan with small, dark spots on the body. Larvae are approximately one inch long when fully mature. They tend to be a brown or green color with darker spots on the surface of its body. The head capsule is a mottled brown color.

Sod webworm larvae overwinter several inches deep in the soil. In the spring, the larvae move upward and feed on new grass growth. In the summer, the larvae bury deeper into the soil to pupate. After two weeks, the new adult moths emerge at night to mate and lay eggs. There are usually two generations per year.

Injury: Larvae attack the leaves and stems of turfgrass just above the crown. As webworm larvae mature and continue to feed, large, brown patches characterize the injured turf areas. The most severe damage usually occurs in July and August.

Action Threshold: Generally, the action threshold for sod webworm larvae has been four to six per square foot. Like most turf insects, this number can vary since the more well-maintained, often irrigated turf can withstand a high threshold number before severe damage starts to occur.

Management: Cultural, biological and chemical controls are all effective at suppressing sod webworm populations. There are also resistant turfgrass varieties that can be planted in areas subject to constant infestations.