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Emerald ash borer found in seven more Maine towns

Nov 24, 2020
Courtesy of: Maine Department of Agriculture, Conservation and Forestry Maine Forest Service entomologist Colleen Teerling girdles a tree for emerald ash borer monitoring in Portland’s Payson Park in May. The tree was among those found to have evidence of EAB.

Augusta — The Maine Department of Agriculture, Conservation and Forestry's Maine Forest Service reports evidence of spread of emerald ash borer within regulated areas of Maine.

This fall, EAB infestations were confirmed in the towns of Van Buren in Aroostook County, Gorham in Cumberland County, and Ogunquit, Parsonsfield, Shapleigh and South Berwick in York County. Targeted surveys by Forest Service staff to locate potential future biological control release sites uncovered the first detected infestation in the York County town of Newfield.

EAB was first detected in Maine in 2018 in both Aroostook County and York County. It was also found in 2019 through trapping in Cumberland County. These detections have led to quarantine regulations in all of York and Cumberland counties and parts of Oxford and Aroostook counties.

Although EAB has not been detected in any new counties in 2020, Maine Department of Agriculture, Conservation and Forestry monitoring programs show EAB populations are expanding within already regulated Maine areas.

Each spring, Maine Forest Service staff and volunteers from many sectors help detect EAB by participating in the girdled trap tree network, an EAB monitoring program. Girdled ash trees are attractive to any EAB in the immediate area. The trees are felled in the fall, and sections of them peeled to look for EAB activity. These trap trees provide a good low-tech detection tool that can be used wherever ash trees grow.

“The girdled trap tree network is critical to our response to emerald ash borer in Maine,” explained DACF forest entomologist Colleen Teerling. “Most of the six biological control release sites established in York County in 2020 were identified through this program, and every year since 2018, this method has provided us with first detections in towns.”

In 2020, at least 34 trees were girdled across eight of Maine’s 16 counties, and nearly all have been processed. Over the past 10 years, this processing has been a social event, where interested landowners, forest managers, and others could participate in the sampling. This year, to reduce the risk of COVID-19 transmission, processing was conducted by MFS, city of Portland, and Acadia National Park staff.

Of the 33 trees processed, nine showed signs of EAB, including exit holes, larval galleries (the tracks etched into the bark and sapwood of the tree as the larvae feed) and EAB larvae. The nine positive trees were within the area currently regulated by the EAB quarantine.

First detections for a town occurred in Gorham (one tree), South Berwick (one tree) and Van Buren (one tree). Additionally, the first evidence of within-tree damage was found in Grand Isle (three trees, positive traps in 2018), Frenchville (one tree, positive trap in 2018), and Portland (two trees, positive trap in 2019). A positive tree was also found in South Berwick.

Highlighting the importance of all Mainers in detecting forest health issues, observations from landowners and foresters have turned up EAB infestations in three York County towns: Ogunquit, Parsonsfield and Shapleigh.

“The Maine Forest Service is extremely grateful for the continued support of the public in responding to EAB,” Teerling said. “In particular, we thank the volunteers in the girdled trap tree network who contribute their time and their trees and people who observe damaged trees or suspicious insects and then make an effort to report them.”

Data from monitoring help inform quarantine regulations, guide management decisions about ash trees in forest, urban, and landscape settings, and determine the best locations for release of EAB's natural enemies (biological control).

The spread of EAB in southern Maine, which is on the leading edge of the insect’s distribution, is more significant than that in the smaller infestation center in northern Maine. In both cases, the natural spread is inevitable and may be slowed using biological controls to reduce population and careful ash management. A more significant impact on the spread can be had through targeting human-caused movement: by observing best management practices for handling ash within regulated areas, following quarantine rules, using local or heat-treated firewood, and avoiding using ash in new tree plantings.

How can you help?

If you girdled an ash trap tree and it has not been processed, email or call the Maine Forest Service Insect and Disease Lab at 287-2431.

If you purchased an ash tree from Lowe’s in Maine this year, report it to or call 287-7545. (As of Nov. 13, 30 of the 36 trees sold had been located.)

If you suspect you have seen emerald ash borer or evidence of its attack on trees in Maine, report it.

To participate in next year’s girdled ash tree survey, email or call the Maine Forest Service Insect and Disease Lab at 287-2431. They will contact you in the spring.

Follow best management practices and quarantine rules when handling ash.

Spread the word, not the bugs: Use local or heat-treated firewood.

For more information on emerald ash borer in Maine, visit

Evidence of emerald ash borer infestation includes larval galleries etched into the sapwood. (Courtesy of: Maine Forest Service)
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