The Browntail Moth (Euproctis chrysorrhoea) was accidentally brought to Massachusetts from its native Europe in 1897, and soon after spread to the rest of New England and also moved into New Brunswick and Nova Scotia. The caterpillars have a huge host range of plants that they feed upon. However, they especially love oak, apple, crabapple, pear, birch and cherry trees. In addition to other hardwoods, they’ll also devour rose bushes that they encounter in the landscape after being dislodged from their primary host trees due to wind or other disturbances. UMaine researchers also recently discovered that at least the later-instar caterpillars can also survive on conifers.
A major problem with this insect stems from the fact that the caterpillars and cocoons are armed with defensive, barbed hairs which break off and–for many people exposed to them—cause skin rashes, headaches, and sometimes breathing difficulties. The reactions on the skin can mimic insect bites in appearance and sensation, causing people to sometimes mistake them as signs of mite, flea, or bed bug infestations.
The moths are attracted to light, fly at night, and are active in July and August. They have a wingspread of about 1.5 inches (36-42 mm). The wings and midsection are solid white on both the male and the female. The abdomen has brown on it, and the brown coloration extends along most of the upper surface of the abdomen in the male [male example], whereas in the female, the top (upper/dorsal surface) of the abdomen is white, but the tuft of brown hairs at the very end is considerably thicker/wider compared to the male [female example]. Fortunately, the hairs on the adult moths are not toxic so those hairs do not cause a skin rash.
Photos and Additional Information:
- Browntail Moth – Information and Updates (Maine Forest Service) (includes a video on removing browntail caterpillar nests)
- Frequently Asked Questions (FAQs) about Browntail Moth (Maine Department of ACF)
- Maps of Winter Web Surveys and Exposure Risk (Maine Forest Service):
- Management Resources:
- Licensed Pesticide Applicators Willing to Treat Trees for Browntail Moth [pdf] (Maine Forest Service – 2022)
- List of Licensed Arborists Willing to Prune Browntail Moth Nests (pdf) (List provided by the Maine Department of ACF)
- In the News:
- Notes to Consider:
- Many people confuse the nests and caterpillars of Fall Webworm with those of the browntail. Nests containing Fall webworm caterpillars are quite large and can be seen throughout August and September in a wide variety of hardwood trees.
- February is an ideal time to remove their nests — See also: Using Aerial Drones in an Innovative Way to Remove Browntail Moth Nests (YouTube video) — This technology is now being used by Mann’s Lumber & Tree (Litchfield, Maine) and also–if you are in Kennebec County or the Belgrade Lakes region: Aerial Browntail Clipping