It’s August, and that means it’s time to check your trees — maple, ash, birch, poplar, willow — to make sure they are healthy, strong, and pest-free.

We know the damaging effects emerald ash borer and gypsy moth can have on our tress. During National Tree Check Month, another big threat in Minnesota is the Asian long-horned beetle — a big, black and white spotted invasive pest that attacks 12 different types of trees. ALB could totally devastate trees in your community, so we urge you to examine them now.

ALB’s preferred host tree is maple, so check those trees first. Look for round exit holes, chew marks in the bark, sawdust-like material on the ground or on tree branches, dead branches, and tunneling in cut wood or fallen branches. Also look for adult beetles on trees, walls, outdoor furniture, cars, and sidewalks. The beetle is about 1 inch to 1.5 inches long, with six legs and a shiny, jet-black body with white spots and two long black-and-white antennae.

The ALB can attack trees anywhere, so Minnesota’s hardwood trees are at risk. Once a tree is infested by the beetle, it must be removed to help save nearby trees. Today, the U.S. Department of Agriculture and its partners are eradicating ALB from areas in Massachusetts, Ohio and New York — in total over 178,000 trees have been cut down because of the pest. That’s why we want all Minnesotans to check their trees this month. Early detection is the key to protecting our trees.

It only takes one person to spot and report an invasive insect. Thanks to diligent residents we have quarantined a Minneapolis neighborhood for gypsy moth to limit the insect’s destruction, stopped furniture infested with wood-boring insects from being widely distributed in the state, and identified new emerald ash borer finds which led to better management decisions. Asian long-horned beetle could show up anywhere in the state, but you could help prevent its spread.

Sometimes we take trees for granted; we don’t think about how much they contribute to our quality of life. Trees serve as wind breaks and sun shields, they muffle noise and block unsightly views. They help conserve energy and water. Trees prevent soil erosion, provide habitat for wildlife and clean the air. For all trees do for us, this month we’re asking you to take 10 minutes to check yours. If you see something, report your findings by calling the Minnesota Department of Agriculture’s Arrest the Pest info line at 1-888-545-6684 or report online at

Join us during National Tree Check Month. Go outside and check your trees.

Erin Stiers is Minnesota’s state plant health director for the USDA and Geir Friisoe is the state Department of Agriculture’s director, Plant Protection Division.

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