Tent Caterpillars Start to Appear in April Forest tent caterpillars cause damage in the larval, or caterpillar, stage. Caterpillars are a greyish- brown color with bright blue and yellow stripes running down the sides of their body. The back of the caterpillar has white shoeprint/ keyhole markings. Larvae also have fine white hairs over their body but are not a stinging caterpillar. These caterpillars, although called tent caterpillars, do not make an actual tent like others in their group. Other tent caterpillars make a web between two branches… Read More →