The larvae feed on the leaves of more than a hundred kinds of fruit, nut, ornamental, and woodland trees. In Oklahoma, persimmon and pecan are most commonly infested and black walnut and hickory are also common hosts. They also target sycamore, birch, and redbud in years of heavy infestations.
Moths emerge from overwintering pupae in late spring (late April to May) and lay clusters of up to 500 greenish eggs on leaf surfaces of host trees. The eggs are partly covered with white hairs or scales and usually occur on leaves near the ends of branches. Depending on the weather, tiny larvae hatch from eggs in early June. Larvae immediately begin weaving their webbing over the leaves at the end of branches. The web is small at first, but soon becomes large as the larvae extend the web to cover more leaves. Feeding is done entirely in the protection of the web. Only the tender portion of leaves are eaten, leaving the veins intact. As the larvae grow, the web becomes filled with dead leaves, cast skins, and feces. When full grown, they crawl down the tree to spin a cocoon and pupate in the ground litter in July. Most commonly, there are two generations a year--the first in early June (into July) and the second and normally the largest and most damaging generation of larvae present in August and September (sometimes into early October). Larvae from the second generation remain in the pupal stage until the next spring, when the moths emerge to begin the cycle again. In some years we have more than two generations.
The moth is satiny white and may have dark spots on the forewings. They have a wing span of slightly over one inch. The larvae are about one inch long when full grown and are pale yellow with dark spots down the back. The body is covered with long, silky, gray-white hairs.
Larvae feed on foliage, creating a webbing on the tips of branches where they aggregate and feed in mass. Larvae confine their feeding to leaves they have covered with webbing and characteristically web only the outer ends of branches. One or more branches may be defoliated, often with no damage to the tree other than appearance. Early defoliation can damage tree vigor (winter survival), yield and nut quality for that growing season. In addition, nut production in the following year can be affected if defoliation is extensive too early (before mid to late October) in the season.
Small larvae and their small webs may be cut out and destroyed, but larger larvae or those high in trees will need to be treated to achieve control.