A single defoliation can kill some evergreens, but usually two or more defoliations are needed to kill hardwoods. Besides causing destruction or decline of the trees, loss of aesthetic, recreational and watershed values of ornamental trees, parks and forests occurs. Caterpillars cause a public nuisance. Small larvae chew pin holes in the leaves whereas larger larvae either partially or completely consume the leaf from the outer margin inward. They are often found on trunks of trees or underside of larger branches.
Small larvae are dark brown to black and very hairy.
Pupae are brown and teardrop shaped. A few threads of brown silk hold the pupae in place on the tree trunk. Females have white wings with dark markings and a tan to buff colored body. Females are heavy bodied and do not fly. The eggs are round, black to brown in color, and deposited in masses of 100 to 600 eggs in July and August.