The emerald ash borer, an invasive beetle that infests and kills native ash trees, has spread further into central Maine.

The Maine Forest Service is trying to reduce the infestation, and on Friday announced the expansion of an emergency order restricting any materials that may transport the beetle, including ash trees, green ash waste and ash firewood. 

Emerald ash borers leave telltale S-shaped tunnels in the bark of ash trees. Brianna Soukup/Staff Photographer

Emerald ash borer infestations have recently been found in Corinna and Newport in Penobscot County and in Andover and Woodstock in Oxford County, the forest service said. 

The emergency order covers Androscoggin, Kennebec, Knox, Lincoln, Sagadahoc and Waldo Counties, and parts of Aroostook, Franklin, Oxford, Penobscot, Piscataquis and Somerset Counties.

The emerald ash borer is a small wood-boring beetle originally hailing from Asia and first identified in the U.S. in the Detroit area in the early 2000s.

The beetle attacks native (not mountain) ash by burrowing through conductive tissue, cutting off the flow of food and nutrients and eventually killing the tree, typically within five years.


Signs of infestation include “blonding,” which is the result of woodpeckers peeling away the outer layer of bark to look for the beetle larvae to feed on; bark falling off; S-shaped tunnels left by the beetles on the bark; and D-shaped holes made by the beetles as they exit the tree. Abnormal shoots and sprouts also may appear as the tree compensates for the damage done by the beetles.

Emerald Ash Borer

An arborist in Newport discovered the woodpecker damage, and crews in Andover and Woodstock found the damage during routine surveys.

The invasive beetle was first discovered in Aroostook County in 2018 and in York County later that year. In Cumberland County, it was detected first in Portland in 2019. It threatens all 400 million of Maine’s ash trees.

The Forest Service will host hybrid listening sessions in April to gather input on emerald ash borer regulations. There will be meetings in Augusta, Old Town and Houlton. 

Residents are asked to report suspected emerald ash borer damage by emailing locations and photos to  

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