Fall webworm larvae are pale greenish-yellow with either black or redheads. They have two rows of black spots along their backs and scattered long hairs along with their bodies. The caterpillars transform into white moths in the spring.
Fall webworms prefer fruit and shade trees and can be found throughout the United States and Canada. The most commonly affected tree species include:
Large masses of webbing on the ends of tree branches are the most noticeable sign of fall webworms. Other signs may include eggs on the bottoms of leaves and skeletonized leaves
and branches. Each adult female moth deposits 200-300 eggs on the underside of leaves, and in a couple of weeks, the caterpillars hatch and immediately start to feed and build webs over the infested branches.
If possible, pruning and destroying the nests is the fastest way to clear the invasion. Promoting the tree’s vitality through fertilization, mulching and proper watering for trees that are attacked may also help restore the trees’ health. While the larvae are small, treating them with insecticides helps to destroy current infestations. Ask your local arborist which method is best for your property.