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Protecting Our Forests Against Invasive Species

In August, the USDA and Maine Department of Agriculture, Conservation and Forestry ask the public to check the trees in their communities and forested properties for invasive insects. Taking just 10 minutes to check the trees around you is essential for early detection.

While August is a peak time of the year to see adult wood-boring insects and other invasive pests, it is not the only time of year that invasive pest activity is visible in the forest. Familiarity with the trees around you as well as the invasive species to watch for can go a long way in protecting our forests against these unwelcome critters.

There are four invasive species that you should be particularly aware of right now.

Asian longhorned beetle

The Asian longhorn beetle is a wood boring beetle that develops and reproduces within deciduous hardwood trees. Attacked trees will eventually die. The Asian longhorn beetle has been found in Massachusetts, New York, and Ohio, where quarantines are in place to prevent spread.

What to look for--The Asian longhorned beetle is a large, more than 1-inch black-and-white beetle. Look for oval or round wounds on the trunk, branches, or bark of maples and other hardwood trees where females have chewed out sites to deposit eggs.

Emerald ash borer

The emerald ash borer has already been found in York, Cumberland, and Aroostook Counties in Maine. One of the most serious invasive species currently threatening Maine's forests, this creature can cause injury or death to all ash of the species that grow in Maine.

What to look for--The emerald ash borer is a small, less than one-half inch metallic green beetle. Look for small, one-eighth-inch "D" shaped exit holes in the bark in addition to sawdust-like waste under the bark. Other signs include woodpecker feeding, crown dieback, and epicormic shoots.

Oak wilt disease

Oak wilt disease is a deadly fungal disease. Found in other parts of the U.S., the closest known infestation is currently in New York. The disease, which causes wilting and leads to mortality, is spread by sap-feeding beetles that carry spores from infected to healthy trees.

What to look for--Watch for a sudden wilt of oak leaves during the summer months.

Spotted lanternfly

The spotted lanternfly is not very picky about what it devours, making it a huge threat to agriculture as well as forests. Although adults are brightly colored, the insect often hitches a ride as dull-colored egg masses. Adults will lay eggs on just about any type of vegetation.

What to look for--Watch for the brightly colored adults and dull-colored egg masses. The spotted lanternfly does not appear to be in Maine, but the best approach is education and awareness about this new potential pest.


If you find any suspected invasive pest, take a picture and send it to Protecting against terrestrial invasive species is important to protecting our extensive network of public and 7 Lakes Alliance lands and easements--and your backyard! Your help is needed to keep an eye out for these invaders in the gorgeous Belgrade Lakes region.



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