Tent Caterpillars
Tent caterpillars attack several kinds of broadleaf trees and shrubs and produce unsightly webs, or tents. Trees with substantial defoliation will have reduced growth and vigor. The caterpillars often occur in large numbers which can be a nuisance around homes.
Eastern Tent Caterpillars
Eastern tent caterpillars feed on new leaves, forming small webs within a few days after hatching and enlarging the webs as they grow.
Trees infested with several tents are often totally defoliated. A single occurrence rarely kills a tree, but it does reduce growth and makes the tree more susceptible to other hazards such as drought, freezing, or disease.
Eastern tent caterpillars grow to over 1½ inches long. They are brightly colored and have a solid white line down the center of the back and long hairs on their bodies, mostly along the sides.
Forest Tent Caterpillars
Forest tent caterpillars build mats of webbing rather than tents. They forage in all directions from these mats but return to the colony when not feeding. Caterpillars feed actively for five to six weeks.
In large numbers forest tent caterpillars can cause serious defoliation to host trees. Usually their numbers are moderate and most of their feeding injury goes unnoticed. The larvae can sometimes be seen clustered in a large group on the trunk of the host.
Forest tent caterpillars are about 2 inches long, mostly blue and black, with a row of white, footprint shaped markings on their backs, and many hairs along the edge of the body.
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Identification and Control Information
- Tent Caterpillars—Maine Forest Service
- Eastern Tent Caterpillar (PDF)—University of Wisconsin Cooperative Extension
- Fact Sheet: Eastern Tent Caterpillar—University of Kentucky Cooperative Extension Service
- Forest and Eastern Tent Caterpillars—University of Maine Cooperative Extension
- Tent Caterpillars (including eastern and forest tent caterpillars and fall webworm)—University of Kentucky Cooperative Extension Service
More Information
- Maine Forest Service: Conditions Reports (updated regularly) including annual summary reports
[Photos, left to right: Catherine Herms, The Ohio State University, Bugwood.org; Joseph O'Brien, USDA Forest Service, Bugwood.org; Pennsylvania Department of Conservation and Natural Resources - Forestry Archive, Bugwood.org; R.C. Morris, USDA Forest Service, Bugwood.org; Whitney Cranshaw, Colorado State University, Bugwood.org; Gerald J. Lenhard, Louiana State Univ, Bugwood.org]