Webby tents can often be seen on the tips of tree branches in fall. Apples, willows, birch, and ash are just a few of the more than 100 species that can be infested. These webby tents are the home to the fall webworm.
Fortunately this is a cosmetic problem. The worm-like caterpillars generally feed late in the season and only on the leaves of one or two branches.
Birds, parasites and other predators usually keep the populations of this North American native pest under control.
If the damage has been severe or you can’t abide the looks, use an eco-friendly control. Gently knock the webs out of smaller trees. Then dislodge the caterpillars with a strong blast of water.
Or treat trees early in the season with Bacillus thuringiensis. This bacterial insecticide kills only true caterpillars. Apply to the leaves in and around the nest. You’ll have the best results when the caterpillars are small.
A bit more information: The webby tents you find in the branch crotches of cherries, crabapples, apples and other deciduous trees and shrubs in spring is the eastern tent caterpillar. Birds, toads and other insects help keep this pest under control. You can knock the tents out of the tree or treat with Bacillus thuringiensis kurstaki if control is needed.