Fall Webworms Start Making An Appearance

Fall webworms typically form nests of loose webbing over the tips of tree branches. A rake or pole may also be used to roll up nests and remove them from the tree. Detached nests should be placed in a container of soapy water overnight to drown caterpillars. - Photo credit: DNR

[photo credit: WDNR]

MADISON–Web-like nests of fall webworm caterpillars, a common native pest active from July through September in Wisconsin, are beginning to appear in parts of the state.

“Fall webworms are rarely large enough to cause lasting damage to trees, but the presence of nests and feeding damage from caterpillars can greatly affect how the tree looks,” says Todd Lanigan, forest health specialist for the Wisconsin Department of Natural Resources.

The fall webworm (Hyphantrea cunea) feeds on leaves of almost all shade, fruit, and ornamental trees and shrubs, except for conifers, throughout most of the U.S. and southern Canada. They typically form nests of loose webbing over the tips of tree branches.

“Trees typically recover from feeding damage on their own, but defoliation for more than two or three years in a row could make trees more susceptible to diseases and other problems,” he says.

If intervention becomes necessary, one of the easiest ways to manage fall webworms is to simply tear open the nests with a rake or pole. [Read more…]