Spider Tents on Oak Trees

A type of caterpillar weaves tents among oaks.

A hairy caterpillar known as the fall webworm builds elaborate nests among the foliage of many trees, including the oak. The Maine Department of Conservation advises to employ a forked stick against these tent caterpillars and their constructions.

Fall Webworm

Fall webworms (Hyphantria cunea) often invade oak trees and form what appear to be spider tents across the leaves and branches. These insects make their presence known in late summer and fall, building silken nests of webbing, usually among leaves near the ends of branches. They feed within these tents.

Effects

The feeding typically does not bring about any significant damage, although the fall webworm lays eggs on the undersides of leaves and may multiply as many as four generations each growing season -- especially in warmer climates. In extreme cases, defoliation of the tree may occur.

Prevention/Solution

Chemical insecticide does not penetrate the nest but may affect young larvae outside of it. Natural enemies such as birds, wasps and flies also help to control the fall webworm and the presence of what looks like spider tents on an oak tree. Gardeners who wish to avoid using insecticide can remove the tents by hand.

References

• Cooperative Extension System
• Maine Department of Conservation: Fall Webworm