Fall Webworms in Arkansas: Silken Nests, Minor Damage

NW Arkansas trees (black walnut, oak) have 1-ft silken webs with caterpillars. Owner asks ID, lethality, and treatment for high nests.

ID: Fall Webworm

Native, 85+ hosts (pecan, walnut, elm, hickory, fruit trees, maples). Late-season feeding; nests at branch tips.

Impact

Little health damage (late season). Cosmetic. Outbreaks every 4–7 years.

Control

• Bt on young larvae (cover leaves near nests).
• Sprays (carbaryl, diazinon, acephate) with pressure to penetrate web.
• Systemic soil drench for tall trees.
• Hand removal of low nests (forked stick).

High nests hard to reach; systemic or professional spray may be needed.