In early spring, larvae begin feeding on aspen, blackgum, sweetgum, oak, birch, ash, maple, elm, and basswood. The larvae do not form a communal tent, rather individuals build small silken mats on the trunks of host trees which they use for resting cover. Caterpillars have whitish keyhole-shaped markings down the middle of their backs. Adults are small tan moths a little over 1.5 inches long. One generation occurs per year.
Outbreaks can be severe, since natural enemy populations are often poorly developed.
Small, black, hairy larvae hatch from egg masses in April and May and begin feeding on a wide variety of host trees. Preferred hosts, however, include oaks, apple, alder, basswood, hawthorn, aspen, and willow. Caterpillars do not build a nest or web. As they mature, they often feed at night and move down the tree to take refuge in shady places during daylight hours. Feeding stops around late July, larvae pupate, adults emerge and lay eggs in August.