Several browntail moths have found a home at the post office in Somesville. These moths are an invasive species that lay eggs and hatch into the browntail caterpillar. Hairs of the caterpillar can cause skin and lung irritation and the caterpillars can be a threat to the health of trees and bushes.  ISLANDER PHOTO BY SARAH HINCKLEY

Browntail moths: look, but don’t touch



BAR HARBORSome people think moths are icky. But Carol Muth is such a fan of the winged creatures that she spends much of her time photographing them. 

A few years ago, Muth, a resident of Town Hill, helped with a study of browntail moths and caterpillars in this area. She didn’t see a lot of the white moths with the fuzzylooking heads, and spotting a browntail caterpillar was even more unusual at that time. This year was different.  

“This is the first time I’ve noticed the caterpillars,” said Muth in a conversation with the Islander on Tuesday. “They were falling out of the oak tree on our property onto our deck and making it onto the side of the house.” 

Browntail caterpillars, and the moths they morph into, are an invasive species that reside largely on the coast of Maine and Massachusetts. Not only is the caterpillar dangerous to trees and shrubs it feasts on, but its hairs can also be toxic to the touch.  

“I always thought it was down the coast a ways,” said Muth about where the species was more prevalent. “I watch moths and photograph them. Every year I’d see a few.”  

When she went to the post office in Somesville about a week ago, Muth saw a slew of the white moths on the side of the building.  

“They have great nighttime lighting, but it attracts a lot of moths,” she said about the white building, on which it can be difficult to detect the small white moth. 

Browntail moths are the adult stage of the browntail caterpillar. In the spring, the browntail caterpillar emerges from an overwintering web and begins feasting on new leaves. They are most attracted to hardwood trees and shrubs like oak, apple, crabapple, hawthorn and rugosa rose, to name a few.  

“We have mature oak trees and we have an apple tree in our yard,” said Muth, who donned gloves to try and remove the caterpillars, but still got a rash.  

While working to clean up the yard, her husband also got a rash on his arms from carrying yard debris rife with the toxic hairs from the caterpillar.  

Most people develop a rash on their skin when it comes in contact with the hairs of the caterpillar. Airborne hairs can also cause respiratory problems. Wetting down outdoor areas before working in them or doing yard work after it rains can prevent the hairs from becoming airborne, according to an informational pamphlet put out by the Maine Department of Agriculture, Conservation and Forestry. 

Once adult moths emerge from their cocoons in July and August, they lay eggs on the underside of leaves. When eggs are found on leaves, remove the leaf and soak it in soapy water for a couple of days before disposing of it.  

As with most moths, the browntail moth is strongly attracted to light. In order not to attract the moths, thus minimizing the opportunity for them to lay eggs nearby, do not leave outside lights on from June through August.  

Caterpillars begin hatching in August and will cluster together in the fall to build winter webs on the tips of branches. These webs are made with leaves tightly wrapped with silk and can hold up to 400 caterpillars. Most often the webs can be found on red oak or apple trees, according to the pamphlet. Wearing protective gear, clip the webs during the winter to reduce the number of caterpillars in the spring.  

Using a dry/wet vacuum with a couple inches of soapy water at the bottom to suck up caterpillars and moths is one way to safely remove them from the side of buildings.  

“They’re not unattractive,” said Muth about the moth and its fuzzy head. “It they didn’t have so many bad consequences, I’d be admiring them.” 

Even so, she is constantly carrying her camera to capture photos of the winged wonders.  

“It’s always a pleasure,” she said about taking pictures of moths. “Sometimes it’s the little ones that have the most interesting features.” 

To find out more about browntail moths and caterpillars and how to mitigate them, visit 

www.maine.gov/dacf/mfs/forest_health/invasive_threats/browntail_moth_info.htm 

Sarah Hinckley

Sarah Hinckley

Former Islander reporter Sarah Hinckley covered the towns of Southwest Harbor, Tremont and neighboring islands.

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