Tent Caterpillars Tree & Shrub InsectTent Caterpillars

Tent Caterpillars attack several kinds of broadleaf trees and shrubs and produce unsightly webs, or tents, which detract from the home landscape. Trees with substantial defoliation will have reduced growth and vigor. Caterpillars also can be very common and thus a nuisance as they move around the exterior of a home. The key to eliminating tent caterpillar problems is early detection and use of appropriate cultural or chemical control measures. In late spring or early summer, female moths deposit an egg mass encircling small twigs or on tree trunks. Egg masses are present on trees during most of the summer, fall and winter. The adult moth uses a sticky, frothy substance called spumaline as an adhesive to attach eggs to bark or twigs. Spumaline also is used as a hard protective covering around the egg mass. Caterpillars, or larvae, hatch from the eggs in early spring about the time host plants leaf out. The eastern tent caterpillar and western tent caterpillar feed on new leaves, forming small webs within a few days after hatching and enlarging the webs as they grow. The web or tent is most often in a crotch of small limbs, and serves as a refuge for the larvae during the night and during rainy spells. Larvae move from the tents to feed on leaves, so damage can be found for some distance around the web. Tent caterpillars feed in groups, and thus concentrate their defoliation.