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Emerald Ash Borer Infestation Spreads To 7 Maine Communities

University of Maine
An emerald ash borer on a leaf.

The emerald ash borer continues its spread across Maine, with seven new infestation sites confirmed this fall.

The Maine Forest Service announced Thursday that the invasive insect, which kills ash trees, has been found in Van Buren, Gorham, Newfield, Ogunquit, Parsonsfield, Shapleigh and South Berwick.

Colleen Teerling, an entomologist with the Maine Forest Service, says the news is discouraging.

“In York and Cumberland County we’re on the leading edge of just a huge infestation from New Hampshire all the way through the eastern half of the U.S., so there are a lot of beetles there, and that’s moving pretty quickly, that front,” she says.

That makes 16 towns in Maine with confirmed ash borer sightings, since it was first discovered here in 2018 at opposite ends of the state — in York and Aroostook counties.

The infestation in northern Maine is smaller and spreading more slowly, says Teerling. No ash borers were found in Aroostook County last year, but one site in Van Buren was identified this year.

The insect had previously been detected in Madawaska, Frenchville, Grand Isle, Portland, Kittery, Berwick, Lebanon, Acton and Limington.

Teerling says the fastest way for the insect to spread is through human activity, such as moving infested firewood and even furniture made from ash wood.

She says there is some hope that biological controls, such as deploying a tiny parasite that uniquely infects ash borers, may make an impact, but won’t likely stop the spread.

At special risk is the native brown or black ash tree, which is culturally significant to Maine’s Wabanaki communities. The tree, which is used in traditional basket making, experiences nearly 100 percent mortality when infected with ash borer.