FRANKLIN COUNTY – Browntail moths have been sighted in Farmington yet again this summer.
Browntail moths, Euproctis chrysorrhoea (L.), have long been seen in coastal Maine. For the past decade, they have been slowly moving inland. As is evident on the UMaine Extension’s 2022 Browntail Moth Winter Web Survey map, the moths are making their way north into Franklin County. There have been several winter webs found throughout Farmington, Jay, Chesterville, New Sharon, New Vineyard, Avon, and Wilton.
A crabapple tree on Academy Street, across from the Farmington Public Library, is infested with caterpillar webs.
The arrival of browntail moths in the area is dangerous for human and forest health. They are an invasive species native to Europe. Their presence in Franklin County means that they are occupying the space and resources of native flora and fauna which will lead to an inevitable decline of important native species.
Browntail moths can also cause severe damage to trees. When the caterpillars hatch, they feed on the leaves of certain trees. According to the UMaine Extension website, they thrive on oak and fruit trees, including apple, crabapple, plum, and cherry so these are the trees to keep an eye on. The caterpillars can feed to the extent of defoliating the tree which can have a severe forest health impact.
In terms of human health, the caterpillars and cocoons have barbed hairs that can cause skin rashes, breathing difficulties, and headaches upon exposure. The hairs are easily broken off and spread by the wind. When the hairs come in contact with human skin, they stick and cause a poison ivy-like rash. The rash is painful and itchy and can last up to a few weeks. When the hairs are breathed in, they can stick in air passageways and cause asthma-like symptoms. These hairs can remain in the air and toxic for up to three years and can have damaging effects on pets and livestock as well as humans.
There is growing concern over the economic impacts of the moth’s damages. Many apple orchards in Vermont have been severely economically impacted and it is possible for these impacts to spread to Maine.
Caterpillars are active during two periods throughout the year, two sets of caterpillars hatching from their eggs and growing until they reach maturity: from April to June and August to October. These are the times when the hairs pose a danger.
It is unnecessary to cut down affected trees, as this only ensures the tree’s death. The defoliated tree will produce more leaves. In order to protect it, the important thing is to get rid of winter webs. The webs are small, located on the very tips of branches, and look similar to paper caught in the tree. They are not extremely noticeable.
After October, the later batch of caterpillars hibernate in their winter webs. This is the time to take preventative measures. February is the ideal time to remove browntail moth nests that are found in trees. This can be done by clipping the infested branches and submerging them in soapy water to ensure that the caterpillars don’t survive.
The adult moths are active from July to August. They can often be seen near streetlights. A simple act of prevention during the summer months is turning off outside lights. Moths are attracted to light and without it, they are less likely to be drawn to local yards and lay eggs in trees. The hairs on adult moths are not toxic, so the danger lies in the earlier stages of life.
Adult browntail moths can be identified by their white hairy bodies and brown tails. Caterpillars can be marked by the red-orange dots on their tails.
The Maine Forest Service’s (MFS) interactive map shows reported sightings in the state.
