Browntail moths are down, but not out

Browntail moth caterpillars can be identified by the two distinctive orange dots at the tail end and white tufts along the sides.

Browntail moth (BTM) aerial surveys revealed a decrease in populations in some areas of the state; however, there are still some towns that have high concentrations of winter webs. These include areas in towns surrounding Sebago Lake, communities in a line from Livermore Falls to Falmouth, and communities in Dedham.

It is not unusual to have single trees or clusters of trees with elevated populations amongst areas with low populations due to the caterpillars’ hitchhiking nature. Communities that have BTM winter webs in their trees should make plans to remove and destroy the webs before April. Clipped BTM webs can be destroyed by soaking them in a bucket of soapy water overnight or by burning them in a contained fire – read our Winter Checklist for Browntail for tips on how to manage BTM in the winter.

If winter webs are not removed and destroyed before next month, the caterpillars will emerge from the winter webs and begin feeding on host trees, causing defoliation and increasing risk for their hairs to cause an irritating rash in humans. Even small numbers of webs can result in thousands of wandering caterpillars come spring (there are dozens to several hundred caterpillars in each web).

There are only a few weeks left to remove BTM winter webs before the caterpillars emerge in mid-April.