There are larvae of several species of moths and butterflies that are referred to as tent caterpillars. They share the characteristic of creating large webs (tents) in the crotch of tree branches. The webs are built to protect the larvae from predators and weather conditions.
The larvae can defoliate trees and shrubs rapidly but rarely cause fatal damage. They can be controlled in a couple of ways – the larvae can be controlled with sprays of Bacillus thuringiensis kurstaki or Spinosad to leaves of the plants they are found on.
Most species of tent caterpillar overwinter as eggs that are attached to small twigs on the trees or shrubs. This makes using horticultural oil during dormancy, but when temperatures are above freezing, an ideal option for control.
The eggs hatch at about the same time as leaf buds begin to unfold. This is the ideal time to begin using Btk or Spinosad.
There are 4 species that are commonly found in North America:
- Eastern Tent Caterpillar
- Fall Webworm
- Forest Tent Caterpillar
- Western Tent Caterpillar
Photo courtesy of Clemson University Department of Entomology, Soils & Plant Sciences, Cooperative Extension Service.