Description and Damage

Fall webworms occur throughout the United States. Larvae feed on the hosts foliage and spin webs around the leaves, usually towards the tips of the limbs. It attacks shade and ornamental trees in urban and suburban areas. Webworms are capable of defoliating an entire tree. The attacks will not necessarily kill a tree but numerous attacks over a few years can cause die back and contribute to plant death.

There are two different types of webworms, orange and black. The two forms differ in color, hosts preferences, and seasonal activity. The larvae are 1-1.5" long covered with dense hair. Orange  race caterpillars have reddish heads while black race have blackish heads.

Hosts

In Alabama, the most common host trees are pecan, persimmon, black cherry, "oriental cherry", sourwood, sweetgum, willow, and red mulberry. During years of "normal" infestations, these are the trees on which webs are usually most common. Webs on pecan, persimmon, the cherries, and sourwood are predominantly, or wholly, orange race, and those on sweetgum, willow, and mulberry are black race. The black race also infests pecan and persimmon but to a lesser extent than the orange race. Several other species of trees serve as hosts for the webworm in Alabama but are infested somewhat less frequently. Colonies of both races have been found feeding on elderberry, hickories, and sycamore, and black-race colonies have been recorded on ash, blackgum, elm, redbud, and baldcypress.