While the eastern tent caterpillars are active in the spring, the fall webworm is active from spring through fall, with three generations occurring each year in Tennessee. Unlike the eastern tent caterpillar, the fall webworm forms large web nests that cover the ends of the branches. They enlarge the nest as they continue to feed for four to eight weeks.

Fall webworms attack at least 88 species of trees in the United States, including persimmon, pecan, hickory, black walnut, sweetgum, American elm, maples and sourwood. This pest has spread to Europe and Asia, where it attacks even more species. While not considered a serious forest pest, fall webworms can defoliate small trees in the landscape.

Where trees are small and only a few caterpillars are present, the following techniques can be used for control:

• Hand destruction of webs and larvae

• Pruning out webs and destroying them

• Destroying egg masses before spring

Chemical control can be used on smaller trees to prevent defoliation. If using an insecticide, choose one that will not adversely affect beneficial insect populations. On larger trees, it is usually sufficient to just remove unsightly webbing that can easily be reached. Do not be overly concerned about webbing high up in the tree.

For chemical control recommendations, consult the Insect and Plant Disease Control Manual, UT Extension Publication 1690, found here. Please contact your local Extension office for specific pesticide recommendations.