The larvae skeletonize the underside of the leaves in feeding. The adults chew holes in the leaves, but the total area consumed is less than larvae. Trees can be turned completely brown from severe populations. Damaging stages - larvae primarily and adults. Larvae are cream-colored when they molt but darken gradually to black.
Eggs are yellow, spindle-shaped and laid on end in clusters on the undersides of the leaves.
The hibernating adult begins to emerge in the spring when foliage appears. These adults feed on the new leaves, cutting holes in them. The eggs are laid for the first generation and they hatch in about a week. In less than a month, usually the adults emerge from pupae which have been formed by larvae on the leaves. Adults of the 2nd generation develop in early July and a 3rd in early August.