They usually feed in large groups, primarily at night, in May and early June. Among their favorite host trees are oak, apple, alder, aspen, basswood, hawthorn, and birch. Many other trees, including maple, pine, and spruce, may be damaged. Fully-grown caterpillars will migrate down from the trees sometime in June to pupate. In July, adult moths emerge.
Female moths release pheromone to attract males.
Egg masses are deposited under loose bark of trees, in woodpiles, on outdoor furniture, and other concealed locations. Egg masses hatch the following spring. This egg case is often moved from infested areas into other regions. Moving with nursery stock, recreation vehicles, firewood, and outdoor furniture are among the ways egg cases may travel out of infested areas. Once in a new location, the eggs may hatch and larva start feeding on trees in the area.