fall webwormsFall Webworms

Fall Webworms create white hair-covered egg masses contain several hundred light yellow eggs. Young larvae are pale yellow with 2 rows of black marks along their bodies. When fully grown, they are covered with whitish hairs that originate from black and orange warts. Larvae vary as to their coloring and markings, but are usually greenish with a broad, dusky stripe along the back with a yellow stripe along the side. The pupal stage is brown. Adult coloration varies considerably from pure white to white with black spots with a wingspread of about 32 mm. This pest over winters as a pupa in a cocoon that is concealed in ground litter, cracks and crevices, or in the soil. Adults first appear in mid-June but may continue to emerge in small numbers during most of the summer. Females usually deposit their egg masses on the undersurface of the leaves. Larvae hatch in approximately 7 days. They immediately begin to spin a small silken web over the foliage on which they feed. As they grow, they enlarge the web to enclose more and more foliage (Image 2). The remains of these nests may persist through winter. These webs may sometimes surround 2-3 feet of infested branch. Larvae are gregarious and feed together until the last molt, after which they may feed independently. Larvae mature in about 6 weeks. Mature larvae leave the web and pupate on or in the soil. There may be one or two generations each year, depending on the geographic location. Proper insecticide use will help to control these type of insects.