Fall webworms, one of our native insect pests, are a perennial nuisance and in some cases a destructive pest. I have seen lots of large nests lately in sourwood,
choke cherry, other Prunus species, sweet gum, and many others. These guys have been recorded on hundreds of plant species. This week I even heard reports of nests in redbuds and crape myrtles.
The best management in most cases is to prune out the nest or just poke it with a stick so parasitoids and birds can get in to kill the larvae. If insecticides become necessary you can find recommendations in the Southeastern US Pest Control Guide for Nursery Crops and Landscape Plantings.
Usually, insecticides are not necessary. Fall webworms upset people because they are ugly not because they damage trees that much. If it seems like fall webworms are around all the time, not just fall, it because they are. Here in NC fall webworms have at least two generations per year and are active throughout the summer.