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MARCH 30, 2023 - Browntail Moth has impacted Yarmouth in previous years, but it has been since 2019 when the most recent treatment methods were implemented. This pest is known for its toxic hairs, which can cause highly-irritating rashes similar to Poison Ivy and respiratory issues, and for its ability to defoliate trees and shrubs.


Most recently, Browntail Moth nests have been identified during the winter's "nest count." Nests are noted in various areas in Yarmouth, but not as substantial nor as widespread as 2019.  


For 2023, a spot treatment method will be put in place to help slow the expansion of this pest in the near future.  In an effort to protect the Town’s residents and its green space in a low-impact, environmentally-friendly manner, while also preserving the health of the trees and shrubs, the Town will be treating select Town-owned trees on public properties beginning this week. Town employees and volunteers will be selectively clipping out nests in trees that are reachable by ladder and trucks. To treat the larger trees, Hawkes Tree Company has been contracted for assistance. 


For taller trees or trees along the waters, the Tree Warden will oversee Hawkes Tree Company who will engage in spray and injection treatments. The chemicals used this year will be selected according to the timing including weather conditions and proximity to water bodies.  The contractor and Town representatives will determine whether to use:


For foliar (spray) treatment:  CROSSCHECK BINFENTHRIN or CONSERVE SC;

For injectable treatment:  TREEAge or ACE-Jet


The treatments will begin in the early morning hours and are typically completed by 11:00am.  We will cover as many areas as possible and will prioritize locations based on the level of infestation and amount of use of the public bicycle and pedestrian routes.  Property owners will be notified starting the week of April 3rd whether trees on their property are considered.  Public properties, including parks and open spaces, will be posted in advance of the treatments and will be closed to the public for a brief period.

Click here for an FAQ for this upcoming BTM process.

Click here for Chemical Data Safety Sheets:

For additional questions, please email Scott Couture, Yarmouth Tree Warden:


Browntail Moth caterpillars proliferate throughout Maine. The insect feeds on the leaves of many common hardwood trees and shrubs in Town.


It has tiny barbed hairs that can cause a skin rash and respiratory difficulties, which can last anywhere from a few hours to several weeks. The tiny hairs break off the caterpillars and are everywhere in infested areas; on trees, lawns, gardens, decks, picnic tables, and in the air. The hairs can remain toxic for up to three years. Wind or activities like mowing or leaf blowing can stir up the hairs and cause a reaction for months, even after the caterpillars become moths.


In spring and as soon as the earliest leaf buds open, Browntail Moth caterpillars feed on the leaves of many hardwood trees and shrubs including Oak, apple, crabapple, cherry, hawthorn, shadbush, serviceberry, and rugosa rose. Infestations can cause reduced growth and branch dieback. After a couple of years at high population levels, Browntail Moth caterpillars can cause the trees and shrubs to die.

The caterpillars then form filmy cocoons between leaves on trees, under eaves, picnic tables, and decks. Adult moths emerge from their cocoons in late July and fly to the tops of trees to remain over the winter months. In the next spring, the process begins again.




The Town of Yarmouth does not spray insecticides on private or public lands for any insects— including Ticks, Mosquitos, or Browntail Moth Caterpillars. So residents and visitors should take steps to protect themselves. Options include:


● Learn to identify the Browntail Moth caterpillar: it is dark brown with a broken white stripe on each side and two conspicuous red spots on the back. It typically grows to 1.5 inches in length. In July and August, the Browntail Moth has snow-white wings and a tuft of dark brown hair on the tip of the abdomen.

● Wear long sleeves, pants, hats, and gloves in affected areas.

● Wash clothes and body after leaving infected areas.

● If you are at risk of respiratory complications, please make additional considerations.

● Avoid leaf piles and areas that have not been raked or blown.

● Contact your physician if you have contracted a severe rash.

Maine Forest Service: (207) 287-2431

Maine Board of Pesticides Control: (207) 287-2731

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