Fall webworm Hyphantria cunea
IDENTIFICATION – In late summer and fall, have you seen webs full of hairy caterpillars on the ends of tree branches? Those are fall webworms, the larvae of a white or speckled moth. The larvae reach 1½ in. long by fall. They’re covered with tufts of gray-brown hair, and their heads can be red or black.
DAMAGE – Fall webworms build tents, which shelter them from rain and predators, on most ornamental or fruit trees, but they usually don’t feed on conifers. Adults lay eggs on leaves in May through August. When the larvae emerge, they build a web and feed inside it, leaving only to drop to the ground in fall to pupate. There can be one to four generations per year, depending on the area — they’re found all over the United States.
CONTROL – Fall webworms don’t usually do permanent damage, but they’re ugly. Natural predators, such as birds, usually keep webworms under control, but infestations are worse in some years. Trim off and destroy affected twigs. If you can’t reach them, or if the limb is too big to remove, use a stream of water to tear the web, knocking a lot of the larvae out of the tree and exposing the rest to predators. You may have to live with the webs for the rest of the year. Chances are, the problem won’t be as bad next year.