Fall webworms make their silken nests at the ends of tree branches. While they are most obvious in the fall (hence their name), they are beginning to build nests now if you keep your eyes peeled. Image: Linda Haugen, USDA Forest Service, Bugwood.org.
It may seem early to be talking about fall, but the fall webworm is already beginning to rear its ugly web. Called the fall webworm because the web nests in which it makes its home are highly visible in the fall, the caterpillar is already observable at a smaller scale in the summer months.
The fall webworm builds its silken nests at the tips of branches, differing from eastern and forest tent caterpillars, which build their silken homes at branch crotches and as mats on trunks, respectively. In North Carolina, the fall webworm mostly attacks pecan, sweetgum, persimmon, sourwood, and black walnut; however, it can feed on the leaves of a wide variety of hardwoods.
Luckily, while their webs may be a visual nuisance, the caterpillars are not considered a serious pest. The biggest complaint is detraction from the aesthetics of landscape trees. Even when the outbreaks are extensive and a tree is completely defoliated, there is little long-term damage to the tree.
But this little critter isn’t just invading non-namesake seasons; the fall webworm has also been introduced to Europe and parts of Asia and has become a significant pest of hundreds of trees and shrubs there.