Behind Dr. Jane Robertson’s home and chiropractic business off Route 3 in Belfast, leafless fruit trees dot the backyard, and the side of her house is splattered with the bodies of caterpillars that she kills with a spray made of vinegar and dish detergent.
But Robertson is all too aware of the many, many browntail moth caterpillars that are still alive and writhing in her trees, spreading their toxic hairs far and wide.
“It’s emotional. They’re just creepy,” she said. “We have thousands of caterpillars. To look up at the trees, it’s just like a horror film.”
The toxic caterpillars have come to midcoast Maine this year with a vengeance. From widespread tree defoliation to an epidemic of the itchy rash caused by the caterpillar hairs, Mainers are using words that include “nightmare,” “epidemic” and “borderline emergency” to describe this year’s infestation.
At Robertson’s house, her apple and pear orchard is being defoliated and, she fears, destroyed by the hungry caterpillars. She also has been plagued with a bad rash on her neck and torso that was caused by 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, to her, 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.”
Robertson said that she has been aware that people who live along the state’s southern coast have struggled with the caterpillars in past years, but those problems seemed far away before they landed in her backyard.
“I thought, ‘Wow, I feel so sorry for those people,’” she recalled. “But it’s like a hurricane or a tornado. Until it happens to you, you can’t understand it.”
‘A real epidemic’
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, spreading out and leading to a lot of defoliation that has been especially noticeable this summer in places such as the midcoast.
Browntail moths feed on a variety of trees and shrubs, but prefer oak, apple, crabapple, pear, birch, cherry and other hardwood trees. Schmeelk said that a healthy tree is likely to survive one or even two years of defoliation, but trees that are stressed by problems such as drought or other insect pressure may have a harder time surviving.
“Generally, if a tree’s been defoliated two or three years in a row, it’s generally not doing too hot and the mortality will be fairly high,” he said. “It’s definitely possible in some of the areas that have had a high browntail infestation, we’re likely to see an oak decline.”
He and others from the forest service have been working with University of Maine professor Ellie Groden and her researchers to find ways to degrade the browntail moth’s winter webs, where they hibernate from fall until mid-April. They’re also searching for pathogens and natural enemies of the moths, and have had some luck with a fungus that is effective at killing the browntails.
“One of the reasons why we theorize that the population started going up in 2015 is that we had some hot, dry summers and then a warmer fall,” he said. “This cool, wet spring we’ve had has actually helped us with browntail. These are the conditions when the fungus starts to proliferate.”
The fungus has even been causing localized population collapses for the browntail, Schmeelk said, which is a good thing.
“Localized collapses will give people some relief,” he said.
Relief can’t come soon enough for Nathaniel Bernier, a Lincolnville arborist who owns Bantam Property Management. He has been inundated with people seeking help for their browntail moth problems, but cannot do anything about it until the caterpillars enter their winter webs.
“It’s got to be tenfold worse than last year,” he said. “I see them in every oak tree … I’m driving from Camden to Lincolnville right now, and my eyes always scan trees. There’s so many. Each oak I go by is completely empty of leaves. These big, beautiful trees. If it’s a healthy oak tree to begin with and then we can get in there and eradicate the nests, they’ll spring back, supposedly.”
He said that the infestation has been the talk of the arborist community for weeks, and he’s starting to get hired to take down defoliated oak trees.
“It’s a real epidemic,” Bernier said, adding that in some ways he fears it could be similar to Dutch elm disease, which wiped out most of the American elm trees in the state in the 20th century. “If there are 100 nests in a 60-foot oak, you’re talking tens of thousands of caterpillars in each tree … we’re in a borderline state of emergency.”
‘A nightmare at my house’
This spring, the Maine Center for Disease Control and Prevention and the Maine Forest Service announced that people with questions about browntail moths can call 211 Maine to speak to a specialist regarding browntail moth biology, management, pesticide options, health concerns, reducing toxic hair exposure and potential public policy and economic impacts. The service, available by dialing 211 (or 1-866-811-5695), is intended to serve as a hub for all state agencies involved in browntail moth issues.
According to the Maine disease control center, the toxic hairs found on the caterpillars, shed skins and cocoons can cause a localized rash similar to poison ivy that lasts from a few hours up to several days. In more sensitive people, though, the rash can be more severe and last for weeks. Hairs also can become airborne and cause breathing trouble and even serious respiratory distress for some people.
Cynthia Whitcomb of Lincolnville feels lucky that she hasn’t suffered breathing problems from all the caterpillars around her home. Even so, their presence has been debilitating.
“It’s been a nightmare at my house,” she said.
Even when Whitcomb donned a suit, gloves, goggles and mask to try to remove them from her garage and deck, she still got the rash. She has found relief for her physical symptoms from a special prescription-strength spray from Kennebec Pharmacy. But in terms of the caterpillar infestation and the public health situation she believes is happening right now, there’s no light at the end of the tunnel.
“I think it is a huge hazard, especially for people with health issues,” she said. “And at this point, I feel like we are trapped inside this house. We can’t go on the deck. Can’t use the trampoline. I feel like we can’t invite people over and we can’t open the windows. The hairs, it seems there’s no end to them.”
Watch: Caterpillars besiege Maine neighborhood