The greatest risk for exposure to the toxic caterpillar hairs which can be found on trees, shrubs, in the air as well as on the body of a Browntail Moth (BTM) caterpillar is between April and July. The second batch of caterpillars hatch from their eggs in August and are active until early October when they enter their winter webs to hibernate until the following spring.

The State of Maine reminds people that it is never safe to handle BTM caterpillars without precautions such as protective clothing, gloves, and a mask. The rash is itchy and the hairs can cause respiratory distress if inhaled. Experts also advise keeping outdoor lights off at night from the last week of June through the first week in August to avoid attracting the moths. It is also recommended not parking under trees with the caterpillars to avoid carrying them home with you.

Browntail moth caterpillars have distinctive orange dots on their tails and a broken white stripe, down their back, while the tent caterpillars have a solid white strip and no orange dots.

Egg masses are usually found on the bottom of the leaves of host trees (oak, apple, crabapple, pear, birch, cherry, and other hardwoods). Clip off affected leaves with gloved hands, long sleeves and a mask. Soak the eggs in soapy water for two days then throw them away.

Pesticides can be also used to control these caterpillars. The Maine Forest Service recommends contracting a licensed pesticide applicator to control browntail moths. Products must be labeled for the site of treatment. Pesticide treatments should be done before the end of May. Later treatments will not reduce human exposures to the toxic hairs.

The Maine Forest Service maintains a list of licensed arborists willing to clip nests or apply insecticides. Contact: Maine Arborist Program (207) 2873891 or contact: Maine Forest Service: (207) 287-2431 for more information.