In this Jan. 22, 2021, browntail moth nests are seen in a crabapple tree in Brewer. Credit: Linda Coan O'Kresik / BDN

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With subfreezing temperatures in much of Maine, yard work is probably far from most people’s minds. But winter is a good time of year to battle browntail moths, the invasive insects that have been wreaking havoc across the state.

Found in Maine and on Cape Cod, the caterpillar stage of the moth has poisonous hairs that can cause a painful, poison ivy-like rash and respiratory problems. The insect also defoliates trees.

Browntail moth caterpillars are not new to Maine — the invasive European species has been here for more than a century — but infestations have been getting worse since 2015, according to Tom Schmeelk, an entomologist with the Maine Forest Service. During the past several years, he said, the populations have been growing, fueled in part by Maine’s warmer and drier weather, spreading out and leading to a lot of defoliation that has been especially noticeable in places near the coast.

Last summer, the moths were prevalent in Bangor as well.

Last year’s outbreak was thought to be one of the worst in 100 years, and webs were found in every county in the state.

“We have thousands of caterpillars. To look up at the trees, it’s just like a horror film,” Dr. Jane Robertson of Belfast told the BDN in June 2019.

At her house, her apple and pear orchard were being defoliated by the hungry caterpillars. She also had a bad rash on her neck and torso from exposure to their tiny, poisonous hairs.

The rash is hot, burning, itchy and uncomfortable — but that’s not even the worst of it. The most distressing part, Robertson said, is feeling that it’s simply not safe to go outside anymore, a thought that is echoed among many Mainers who live in the affected areas.

“You can’t go outside because of this,” she said. “It’s just frustrating.”

The moths hibernate in the winter, inside webs that are visible in the season’s leafless trees. That makes this the perfect time to remove the nests, which are often in the tree’s highest branches.

The nests are a shiny white and cover a few leaves. They are smaller and lighter colored than the nests of tent caterpillars and webworms. Browntail moth nests also tend to be at the tips of branches and most likely on apple and oak trees.

If you are able to reach the nests, you should cut them down and either burn them or drown them in soapy water, according to the Maine Department of Agriculture, Conservation and Forestry. Wear gloves and protective clothing.

For taller trees and larger infestations, you may need to call a professional.

“Winter is the best time to determine what your risk is for exposure to browntail moth in the coming spring and summer,” the department says on the state website.

Removing the nests now while the insects are hibernating is much safer than combatting browntail moths and their larvae in the spring and summer.

Doing this work now won’t eliminate browntail moths from Maine, but it could help make spring and summer in your neighborhood more bearable.


The BDN Editorial Board

The Bangor Daily News editorial board members are Publisher Richard J. Warren, Editorial Page Editor Susan Young, Assistant Editorial Page Editor Matt Junker and BDN President Todd Benoit. Young has worked...