Fall webworm caterpillars produce a web of fine silk in branches of more than 100 deciduous tree species. Some local favorite trees are oak, willow, poplar, elm, linden, ash, and all fruit trees. The caterpillars feed only within their silk nest. Webworm nests become quite unsightly as they expand. Branch tips within the nests become defoliated.
Many caterpillars can be found living in the tent. Full-grown caterpillars are 1″ to 11/4″ long and covered with silky hairs. Their body color can be yellow, green, gray, brown, and black usually with orange, yellow, or black spots or stripes.
There are two varieties of fall webworm, one variety has a black-colored head and the other has a red-colored head. An application of fall seasonal spray during the months of August and September is recommended. Simply pruning out the nests while the caterpillars are still in there is an easy way to control infestation.