ELLSWORTH — This past February was Maine’s first ever Browntail Moth Awareness Month, a fact that serves to illustrate just how pervasive this invasive species has become.
Native to Europe and neighboring countries in Asia and the northern coast of Africa, this prickly pest was introduced to the area by accident in the 1800s. The browntail moth population has fluctuated over the years, but it has been in an outbreak phase since 2015, according to the Maine Forest Service. And while they can be found in greater numbers a little farther to the southwest in Waldo and Kennebec counties, they still pose a serious threat to the local ecosystem and its inhabitants.
As a caterpillar, the browntail moth develops microscopic, poisonous hairs that can cause a severe rash lasting anywhere from a few hours to several weeks if they come in contact with skin. And respiratory issues caused by inhaling the hairs can also be very serious. These hairs carry the same level of toxicity whether they are attached to the caterpillar or if they have become airborne, or whether the caterpillar is alive or dead. And while there are some natural checks on their population growth, such as a certain fungus called entomophaga aulicae that grows during a cold and wet spring, there is no way to eradicate the species on a large scale.
That’s why organizations like the Hancock County Soil and Water Conservation District, and its chair, Mark Whiting, urge residents to act now to help nip this problem in the bud.
“It’s a fairly simple process to dispose of the browntail moth nests,” Whiting explained, as he stood with Kathy Young and Richard Tepper, executive director and caretaker at the Woodlawn Museum, where several nests had recently been spotted.
“And from the beginning of the year to around mid-March, depending on the weather, it is safe to touch them because they haven’t developed the hairs yet,” said Jake Meir, a consulting forester who was there to assist with the location and disposal process. “That’s why it’s so important to do it now!”
The first step is to check your trees and locate any nests, which is not always easy. The nests are often incredibly small and high up. The key is to check for one or two solitary leaves toward the end of a branch that have held on through the winter. While these leaves may just be of a heartier stock than their compatriots, it’s more likely that they have been secured to the branch by the moth’s silken web.
Browntail moths spin their nests in early fall, with each nest containing between 25 to 400 larvae. The caterpillars will eventually emerge from these nests after the winter and begin to eat the leaves of their host tree, generally oak, apple, crabapple, pear, birch, cherry or other hardwoods.
“Two years ago, the population was much higher, and they absolutely destroyed my garden,” Whiting lamented. “They ate every leaf on every tree.”
That’s why it’s important to remove the nests even if they are up high in a tree and unlikely to come in contact with humans. The Forest Service warns that long-lasting tree defoliation and branch dieback are major concerns.
If you are unable to reach nests that are up high, the Hancock County Soil and Water Conservation District is willing to help. It purchased a 9-foot, long-reach pruner and is willing to lend it out for a couple of days to anyone who needs it. It can be picked up at the organization’s office at 474 Bucksport Road in Ellsworth.
“We purchased it specifically for browntail moth eradication,” Whiting said. “But if someone wants to prune an apple tree or two of theirs while they have it, we don’t mind.”
Once the nest has been located and clipped, the next step is to remove it carefully from the tree and soak it in a bucket of water infused with dish soap for a couple of days before throwing it away.
“The soap breaks down the casing, allowing for the water to get in and drown the eggs,” Whiting explained.
Burning the nests, while possibly more satisfying, is not recommended. The toxins can still irritate the skin and would be even more dangerous if inhaled, similar to burning poison ivy.
Whiting and Weir say that any action taken now will go a long way in helping to curb the browntail moth population and prevent damage to residents and their gardens in the spring and summer.