Photo by Drees. Webs can cover leaves, clusters of leaves or leaves on whole branches, becoming several feet in diameter. They contain many hairy caterpillars that hatched from one egg mass. Some trees can have a high number of webs. They are covered with tufts of long whitish hairs.
Adult moths are mostly white with dark spots on the wings.
Webs of fall webworms are often confused with other caterpillar-produced webbing in trees. Caterpillars of this and other web-producing species are less hairy and lack the double row of black dots on the top of each body segment characteristic of the fall webworm. Adults emerge in spring after host plants have developed leaves and mate. On the underside of leaves female moths deposit eggs in masses that appear covered with hair. Caterpillars hatch and begin feeding on leaves, spinning silken webs enveloping their feeding sites.