Fall Webworm

These insects are becoming noticeable across the area as they make their nests in trees. These caterpillars are pale-green to yellow to nearly white with black spots and long white hairs. They are often confused with the eastern tent caterpillars that are also in our area however the two can be distinguished by their webs. The fall webworm has a loosely woven web encasing entire branches and the caterpillars feed inside the web while the eastern tent caterpillar has a densely woven web in the crotches or forks of tree branches and they feed outside the nest only coming inside at night or rainy weather. Eastern tent caterpillars are also active in the spring while fall webworm is active in the fall.

The fall webworm feeds on a wide range of trees including birch, crabapple, maples, hickory, pecan, mulberry and walnut. Because this caterpillar only feeds inside the nest they are difficult to control by chemical unless you have a high-powered spray that can penetrate the web. Most of the time it’s easiest to cut the branch with the web off and dispose of it rather than use chemical for control. Unless there are multiple nests on the tree or the tree was already stressed by other pests most mature trees can tolerate a few nests of fall webworm without any damage, especially in the fall.

Have questions? Contact our office where our Horticulture Extension Agent will assist you with questions.

Phone: (316) 321-9660

Email: callae@ksu.edu