Frequently Asked Quesions (FAQs) about the Emerald Ash Borer

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The emerald ash borer (EAB) is a small wood-boring beetle from Asia that was accidentally brought to North America in infested wood.

Like most invasive species, the emerald ash borer can increase populations very quickly. EAB attacks our native ash trees (not mountain ash) in large numbers, tunneling through the conductive tissue and cutting off the flow of water and nutrients killing the trees in five years or less.

The Maine Forest Service estimates that ash makes up approximately 4% of our hardwood forests or about 2% of the overall forest.

• Loss of a food source for wildlife.
• Impacts to the hydrology and soil integrity of riparian and wetland areas.
• About $320 million potential economic impact to forest landowners.
• Loss of a significant street tree in many communities. Removal of dying and dead trees will cost millions of dollars and will change how many communities look.
• Loss of brown (black) ash (Fraxinus nigra), a key material for traditional basketmaking, which is central in the cultural traditions of the Wabanaki tribes of the region.

Emerald ash borer is native to Asia. It has been introduced in Europe and North America. In North America, EAB has been found in 35 states and 5 Canadian provinces since it was first discovered in Michigan in 2002. It was first found in Maine in 2018, in the northern border town of Madawaska. See the maps at for more information.

The beetle itself is very small and may not be easily seen. Most finds are made by noticing signs and symptoms of an infestation on ash trees. The state and federal governments also use various traps, and other monitoring techniques like trap trees and biosurveillance.

TAKE PICTURES AND MAKE A REPORT. If you think you found the beetle, collect it or take a picture of it. You can compare the beetle you saw with some other insects that are mistaken for it. If you see signs or symptoms on an ash tree, take good pictures and report your findings.

Ash that are in good health within a 10-15 mile zone of infested areas can be treated with pesticides as outlined in this information from New Hampshire:
For ash more than 10-15 miles from known infested areas and ash in the forest, pesticide treatments are not recommended.

The answer will depend on your reasons for ownership. You can find guidance in this Maine Forest Service Information sheet:

You can find local resources at and information from the US and Canada at

Ash trees will succumb to attack from emerald ash borer. Spread is likely to be patchy and slow across the state. Trees generally die within 3-5 years of attack. In some states, a small percentage of trees (<1%) in some infested areas have lingered for more than 10 years after attack.

Organisms that rely heavily on ash, including dozens of native arthropods, will also decline or be eliminated.

Industries and individuals that rely on ash will be affected. Infested areas and surrounding locations will be quarantined, which results in restrictions on movement of ash trees, logs, pulpwood, and other raw-wood products. The regulations also prohibit movement of untreated hardwood firewood to areas outside the quarantine.

While thinking about this question, it may be helpful to know that Siberia is within the native range of EAB. Although research has shown that extreme cold will kill many of the overwintering EAB larvae, even our coldest winters will not do more than slow down EAB’s rate of spread. Cold is like a speed bump to EAB; cold may slow it down, but will not stop it and will not protect our trees from EAB.