A dry spring has made for an itchy and scratchy summer along Maine’s coast, the result of a bumper crop of browntail moths. And a state entomologist said Thursday that the worst conditions in a decade could last well into next year.

The culprit for the itchy, oozy rashes is the microscopic hairs left behind by the browntail moth caterpillars that hatched this spring. They have since turned into moths, but their noxious hairs are still swirling through the midcoast and southern coastal Maine region, the only part of the country where the invasive species is found.

Winter web counts for browntail moths were high this year in some parts of Cumberland and Sagadahoc counties and there also were pockets of infestation reported in three other counties, according to the Maine Department of Agriculture, Conservation and Forestry. Browntail moths build their webs in oak and apple trees.

Charlene Donahue, a forest entomologist with the Maine Forest Service, said the number of browntail moths may be the largest in the state in the past 10 years. A dry spring likely contributed to the large population because a fungus that kills the invasive species did not take hold. That means there are more adults laying more eggs, she said.

“The concern is we’re going to have a lot more browntail moths next spring,” Donahue said. “I would prepare for a bad year next year.”

Browntail moth caterpillar hairs can cause a blistery, oozy rash or respiratory distress for people who come into contact with them.


Web surveys conducted by the Maine Forest Service found extremely high levels of over-wintering in the tops of oak trees. Those counts were highest in Bowdoinham, Bath, Topsham, West Bath, Brunswick, Freeport and Harpswell.

Browntail moth webs also showed up in more southerly locations, including Cape Elizabeth, Scarborough, Westbrook, Windham, New Gloucester and Yarmouth.

Pockets of infestation were found in the Kennebec County towns of Augusta, China, Vassalboro and Waterville; in Lewiston and Turner in Androscoggin County; and in Whitefield in Lincoln County. An infestation was found this year at Gardiner High School.

Browntail moth caterpillar hairs break off of the caterpillar and circulate in the air. The dried skin that the caterpillars release when molting also contains the hairs and can cause irritation for people.

“It’s just really unpleasant,” Donahue said.

She said those hairs are problematic because they have fishhooks that stick into the skin and contain an irritating chemical that does not break down for years.


“If you’re mowing any time this summer or you’re raking leaves this fall, you can get a rash,” she said. “You could get rash next year.”


The invasive browntail moth arrived in the United States in the 1880s in a shipment of roses from Europe. They spread through Massachusetts, New Hampshire, Maine and Nova Scotia before the population collapsed, according to the Agriculture Department. It is now only found in North America on the coast of Maine.

A 1904 report written by the University of Maine’s Edith Patch described how the City Improvement Society of Portsmouth, New Hampshire, went to elaborate – if somewhat unusual – lengths to get rid of moths the previous winter. The society gave $50 to the superintendent of schools, who paid children 5 cents a dozen for winter nests. Hundreds of nests were collected by the children and burned in the school furnace.

“In March, groups of Portsmouth newsboys were to be seen scanning the branches overhead and darting off eagerly for browntail nests,” Patch wrote. “About the same time, a Kittery urchin was heard to remark somewhat wistfully, ‘The Portsmouth kids are makin’ their fortune pickin’ brown-tails.’ ”

In the 1980s, an infestation of browntail moths took hold on Casco Bay’s islands, then spread to the mainland. Islands – and later towns on the mainland – used crop dusters to spray pesticides, but that practice was met with resistance from people concerned about the harm it could cause to lobsters and other shellfish.



Jackie Sartoris of Brunswick knows all too well the aggravation and irritation that come with browntail moths. She first saw browntail caterpillars about a decade ago when the side of her house was suddenly covered with them. She grabbed her vacuum and sucked them up, then later made the mistake of touching the vacuum bag. She soon found herself covered in a rash.

“I was lucky it just got on my arms and chest, because if you inhale (the hair) it can be much more serious,” she said. “The itching is enough to drive you crazy. If you do scratch it, it gets worse.”

Most people who come in contact with the toxins develop a rash that will last for a few hours to several days. A smaller number may be more sensitive to the toxins and get a severe rash that lasts for several weeks. One health survey has found that the toxins can cause respiratory distress in 11 percent of the population, according to the state Department of Agriculture, Conservation and Forestry.

Sartoris said her husband, Steve Walker, a wildlife biologist, is very attentive to their property and removes browntail moth nests from their trees every year.

“That’s really critical,” Sartois said, noting that they no longer have issues with the moths on their property.



Browntail moth infestations can be difficult to deal with because of restrictions on using pesticides in certain coastal areas. Also, because the moths are isolated to a small section of Maine, there is no funding for research into how to better control the problem, said Donahue, the forest entomologist.

Donahue recommends that people check their oak and apple trees for moth webs in the fall. They should clip out any webs they can reach, then burn them or submerge them in water. If the webs are too high to reach, a licensed pesticide applicator can treat them in the spring, she said.

In the meantime, Donahue suggests that people who live in the areas affected by the moths take extra precautions to protect themselves, especially during dry weather when the microscopic hairs are more likely to be circulating.

People can wear long pants and sleeves when they mow their laws – or mow when the grass is wet – and avoid sitting under apple and oak trees that show damage from the moths.

“There aren’t a lot of options for people,” Donahue said. “It’s a really tough problem.”

The Department of Agriculture, Conservation and Forestry has more information about browntail moths on its website, along with a list of licensed pesticide applicators willing to treat browntail infestations.


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