08/28/2026
Large webs in late summer: Is it browntail moth?
From Maine Department of Agriculture, Conservation and Forestry
Most commonly, webs larger than a football in late summer are created by the native caterpillar fall webworm and are not created by browntail caterpillars.
While these fall webworm caterpillars can create webs that get very large - sometimes covering an entire tree - they are not a forest health concern and do not cause a rash in humans. At most, their webs can be unsightly for a couple months until they naturally break down in the winter season.
If you see webs in your trees in late summer and want to know how to tell the difference, consider:
- Does the web cover entire branches, or sometimes the whole tree?
- Are there large (greater than 1 inch long), hairy, yellowish-brown bodied caterpillars crawling on or inside the web?
--> You are likely looking at native fall webworm caterpillars.
But, if the web:
- Is only the size of your palm,
- Has silken pathways leading up the branch,
- Has small (~less than 1/2 inch long) pale yellow caterpillars with a black head and two dark spots near its head,
--> You are likely looking at non-native browntail moth caterpillars.
Although it is too late for effective management in the late summer, make a plan to monitor these webs and remove them in the winter season to reduce browntail moth populations on your property. Read DACF's Browntail Moth Brochure for tips on how to recognize and remove winter webs:https://www.maine.gov/dacf/mfs/forest_health/documents/browntail_moth_brochure.pdf
