Each year our pecan tree is invaded by web worms. I've always heard them called Cahaba worms, but I can't find anything on the Internet to support that. I hear also that they're great for fishing, but I wouldn't want to dig through the web to get them, let alone bait a hook with them. Yuck!
Follow-up: The bugs in my tree are stupid old web worms. The worms fishermen like are the Catalpa (catawba) worms. They aren't really worms, but actually caterpillars that only eat the leaves of the Catalpa tree. Isn't it nice to learn something new?