The upper leaf surface remains intact. Note the molting webs along the veins. During the growing season, examine leaves for caterpillars, molting webs along veins on the underside of leaves, and skeletonized patches. The tiny pale-yellow larvae tend to hang from leaves on silken threads. There are two generations per year.
Winter is spent as pupae in white cocoons on trunks and leaves.
First generation moths emerge in April and May and lay eggs on undersides of fully-grown leaves. Molting takes place in small silken webs. Second generation adults appear in July and August. Ornamental trees are especially vulnerable to this insect. Repeated attacks may result in weakened trees with thinning crowns, dieback, and increased susceptibility to attack by wood-boring insects.