WEBWORMS—

This time of year many Ohio trees contain large webs of Hyphantria cunea; commonly known as fall webworms. In spite of their making it less likely you will hug that tree, they really cause very little damage overall.

If you look carefully at any nest right now they likely are well populated with adult caterpillars. Surrounding the heavily webbed area you may notice some defoliation. Except for being an eyesore it generally is not sufficient to damage the host tree. Lots of little dots of feces likely also are visible clinging to the web.

These pests will usually fall to the ground and over winter in the pupal stage (a non-feeding metamorphosis between the caterpillar and adult moth). The adults emerge from late May to July and lay their hundreds of eggs in a layer or layers on the underside of leaves. They will hatch in about a week and the small mass of caterpillars will web over a single leaf. Then as they grow they will enlarge the web until it becomes as visible as they are now.

The adult is a small, mostly white moth in the Family Arctiidae and very hairy. Its front legs have bright yellow or orange patches and its wingspan is 35 to 42 mm (35 mm = 1.38 inches). See small photo.

The nests can be pruned out of the trees, but, burning is not advised because that usually causes more damage to the tree than the caterpillars. Chemical controls include insecticide sprays and merely wetting the nest and surrounding foliage is sufficient.

For those nests out of reach in the tall trees, translocated systemics applied to the soil for root uptake is often used.

Or, better yet, ignore the eyesore, and enjoy watching yet another example of nature taking its course.