While some are long bands found on twigs, others are flattened shapes found on tree trunks or buildings. In both cases, egg cases can be picked by hand or pruned out. Once the caterpillars have hatched, the simplest way to control them is to remove and destroy the larvae and their nests by stripping or pruning them from branches. Burning the nests, a traditional method of control, is no longer recommended because of the fire hazard. Adult tent caterpillars are attracted to lights at night, and females may lay eggs on building surfaces near these lights.
Yellow lights are far less attractive to night-flying insects.
Timing Evening and early morning are the best times to prune or spray because tent caterpillars tend to congregate in their nests at night. Spraying When tent caterpillars are numerous or hard to reach, chemical controls are recommended. Caterpillars must eat a moderate amount of treated leaf to get an effective dose. Thorough coverage of foliage is necessary, and spraying should not begin until early signs of leaf damage appear. The effects of B.t. are not immediately apparent.