Caterpillars rest inside the tents during the heat of the day or rainy weather and depart to feed on leaves during the night. While tent caterpillars can nearly defoliate a tree when numerous, the tree will usually recover and put out new leaves.
Eastern tent caterpillar is not considered as serious a pest as gypsy moth because it feeds early enough in the season that the trees have enough energy stored to put out new leaves since they have not completely depleted those resources yet.
Eastern tent caterpillar is also native to Fairfax County and has many natural enemies. Once the caterpillars are full grown, they stop feeding and begin to wander around on the ground and buildings looking for a protected place to pupate. Keep in mind that by this time, they will no longer be feeding or causing further damage to trees. Prevention and early control is important. Removal of egg masses during winter greatly reduces the problem next spring. Their egg masses are covered with a shiny, black varnish-like material and encircle branches that are about pencil-size or smaller. In early spring, small tents can be removed and destroyed by hand. Larger tents can be pruned out and destroyed or removed by using a long stick or broom handle.