Insects - native

Unknown, cannot identify on Sep 5, 2016

Originally reported as Asian Gypsy Moth (Lymantria dispar asiatica)

Submitter has sample
EDRR Status: No Response/Action Required

Description of specimen

see above (# 1 and 2)

Sorry, no photos available...


Hi, You seem to have a lot of keen observations of tree health! Nice job. I can help rule out a few things for you. First, those caterpillars are not exotic gypsy moth (either the Asian or European subspecies). Gypsy moth larvae do NOT make webs and are only active April-June at our latitude and climate. The adults are present June-Aug, at which point the females lay eggs (the overwintering stage) and die. To learn more about gypsy moth, please visit

Forest health professionals have been getting calls of fall webworm across the Portland metro area and the Willamette valley. These insects form webs in a variety of hardwood trees and shrubs. While they may appear unsightly, they do not pose any long-term risk to tree health as these hardwoods can easily recover next spring with leaf flush. You can physically remove the webs or use soapy water solution. Please do not use fire as some sources on the web say to use.

Emerald ash borer is a top concern to Oregon's ash. They only feed in ash and there are a few key signs to determine whether you have EAB. Check out this excellent resource by OSU Extension. After viewing the website, you will be prepared to rule out EAB or make another submission to this reporting website.

Thanks for the report!


Wyatt Williams
Sept. 9, 2016, 3:52 p.m.