Fall Webworm—Hyphantria cunea
The most notable aspect of this pest is the unsightly silken web that it produces. Many times, there are many of these webs per tree. These webs are started near the tips of the branches and gradually are extended down the branch towards the trunk. Although not considered a serious forest pest, the ugliness of the webs can cause them to be considered a significant pest of nurseries and landscapes.
Webworms enclose leaves and small branches in their nests, unlike the tent caterpillars which make a smaller nest in the crotch of branches. Webs start small, but the caterpillars enlarge them every few days as they grow and consume the leaves within.
Webs contain many hairy caterpillars that hatched from one egg mass.
Caterpillars are slightly more than 1 inch long and covered with long, pale, gray hairs. The body color ranges from yellow to brown with dusky, mottled areas along the sides and two rows of black dots along the back.
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Identification and Control Information
- Fall Webworm—Maine Forest Service
- Entomological Notes: Fall Webworm (PDF)—Penn State Cooperative Extension
More Information
- Maine Forest Service: Conditions Reports (updated regularly) including annual summary reports
[Photos, left to right: Ronald F. Billings, Texas Forest Service, Bugwood.org; Steven Katovich, USDA Forest Service, Bugwood.org; James B. Hanson, USDA Forest Service, Bugwood.org]