A browntail moth crawls on a branch
This 2017 photo by Holland Haverkamp shows a browntail moth caterpillar in Maine. The caterpillars can cause an itchy rash in humans, and a new study by University of Maine scientists states that their spread appears aided by climate change. Credit: Holland Haverkamp / University of Maine via AP

Browntail moths are expected to terrorize Mainers again this summer, but a new map may help you avoid the most-infested parts of the state.

The map, assembled by the Maine Forest Service, predicts the intensity of browntail moth spring infestations based on the number of webs detected in the winter and early spring. Last year’s browntail moth outbreak was the worst the state had ever seen, with the caterpillars’ toxic hairs causing blistery rashes and even respiratory distress for people who came into contact with them.

Between December and April, Maine Forest Service employees drove in teams of two on major roads near known browntail moth infestation areas. The passenger noted which types of trees were hosting the browntail moth webs, the pattern of the webs — a single tree, patchy coverage or continuous infestation — and the average number of webs per tree.

The map’s markers are color-coded to represent the severity of the predicted outbreak. For example, green markers represent fewer than nine browntail moth webs in an area, while dark red markers indicate more than 5,000 webs.

Knox, Lincoln, Androscoggin and Kennebec counties will likely see the brunt of this year’s browntail moth outbreaks, based on the number of webs detected by the Maine Forest Service.

The map is not an exhaustive database of all browntail moth locations in Maine. For example, webs are not always visible from a moving car on the road, and the areas surveyed were ones with known past browntail moth activity. The markers on the map don’t represent exact locations of webs.

Lindsay Putnam

Lindsay Putnam is a senior editor for sports and features at the Bangor Daily News. Lindsay previously worked as an editor and reporter at the New York Post. She's a York Beach native and Colby College...