Fall webworm

Posted On Wednesday September 02, 2020
fall webworm netting
fall webworm netting

The fall webworm (Hyphantria cunea) is usually noticeable on trees in August through to September and later as the nests remain in the tree. Species impacted are Apple, Ash, Cherry, Elm, Maple, Willow, Walnut, and other trees and shrubs.

Damage: Larvae of the fall webworm feed as a colony within nests constructed of webbing. At first, the larvae only skeletonize the leaves. Later as the larvae develop, the leaves are devoured entirely. Injury caused by the webworm is seldom extensive on trees. It is usually the aesthetic value of trees that is impacted from the unsightly large webs.

Control: Damage by the fall webworm can be reduced by removing and destroying the larvae-infested nests. Simply poking holes in the nests to allow birds and wasps to get at the caterpillars helps. Pruning may help but because the webs may engulf large portions of a limb, pruning may unnecessarily remove branches and limbs and could deform the tree.  Chemical control is seldom required. However, if control is sought to be needed, sprays should be applied with sufficient pressure to penetrate through the webbing.