Browntail Moth
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.
A major problem with this insect stems from the fact that throughout much of its life cycle (and especially in the caterpillar stage), it is armed with defensive, barbed hairs which break off and–for many people exposed to them—cause skin rashes, headaches, and sometimes breathing difficulties.
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.
- A typical overwintering nest of immature Browntail caterpillars formed at the end of a crabapple branch (the nest was home to approximately 30 healthy, early instar browntail caterpillars as seen in the adjacent photo) (Orono, ME; 3/14/2022)
- A peek inside a winter nest of Browntail caterpillars with roughly 30 healthy individuals (Orono, ME; 3/14/2022)
- An oak leaf produced in 2021 found on the ground on April 24th, 2022 with signs of a likely cluster of browntail caterpillars inside of it (leaf contents revealed in two adjacent photos) (Etna, Maine)
- Oak leaf with its package of webbing removed for a closer examination (see adjacent photo–with a penny included–to see its contents)
- A cluster of young browntail caterpillars exposed from their protective nest of webbing that was removed from an oak leaf produced in 2021 that had fallen to the ground (April 24th, 2022; Etna, Maine)
- Browntail Caterpillars on a crabapple tree in Waterville, Maine; 5/12/2021 (Photo courtesy of Jamie Graves)
- Browntail Moth (caterpillars feeding on wild apple leaves; Lincolnville Center, ME – 6/5/2019)
- Browntail Moth (late instar caterpillar on a wild apple leaf; Lincolnville Center, ME – 6/5/2019)
- Browntail Moth (late instar caterpillar stage)
- Browntail caterpillar (Euproctis chrysorrhoea) on a rosebush (Etna, ME; 5/22/2022)
- Browntail Moth (example of a spring/early summer-season nest)
- Pupa of a Browntail Moth extracted from its hairy cocoon (southern Penobscot County; 6/15/2021)
- Browntail Moths in Kennebec County (7/1/2021)
- Closer view of some Browntail Moths from the adjacent photo (Kennebec County, Maine, 7/1/2021)
- Browntail Moth (southern Penobscot County, Maine; 6/28/2021)
- Browntail Moths; note the brown ‘tail’ at the end of the abdomen (Kennebec County, Maine, 7/1/2021)
- An example of the skin rash that the hairs from the browntail caterpillars can cause. Staff Photo, taken 5/26/21.
- Example of the early stage of a milder case of a reaction to the Browntail caterpillar hairs on a person’s wrist. Staff Photo (5/26/2021).
- Browntail Moth caterpillar infected with E. aulicae fungus at Lake St. George Park in Liberty, ME. (Photo courtesy of Tom Schmeelk, Maine Forest Service)
Additional Information:
- Browntail Moth – Information and Updates (Maine Forest Service) (includes a video on removing browntail caterpillar nests)
- Recent News (May 12, 2022): Mech interviewed by BDN about impending browntail moth season
- Browntail Moth 2021 Winter Web Moth Survey (pdf) (Department of Agriculture, Conservation and Forestry and Maine Forest Service
Forest Health & Monitoring) Maine Forest Service Map of Exposure Risk (Year 2020) (pdf)- Frequently Asked Questions (FAQs) about Browntail Moth (Maine CDC)
- The same list of Browntail Moth FAQs is also available via the Maine Department of ACF
- 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 at least one arborist in Maine: Mann’s Lumber & Tree (Litchfield, Maine) | List of Licensed Arborists Willing to Prune Browntail Moth Nests (pdf)
- UMaine research connects rising temperatures with browntail moth resurgence (Feb. 17th, 2022)