Check Trees in August for Signs of the Asian Longhorned Beetle

August is Tree Check Month, and the U.S. Department of Agriculture is asking the public to look for and report any signs of this invasive pest that’s not native to Michigan and could cause harm to our environment and economy.

In late summer and early fall, adult Asian longhorned beetles drill perfectly round, 3/8-inch holes to emerge from within tree trunks and limbs, where they spend their larval stage chewing through the heartwood.

After a brief mating period, female beetles chew oval depressions in trunks or branches to deposit eggs.

Sometimes a material resembling wood shavings can be seen at or below exit holes or coming from cracks in an infested tree’s bark.

The Asian longhorned beetle was first detected in the U.S. in 1996, when a Brooklyn, New York resident noticed a large, black beetle with irregular white spots and black-and-white banded antennae and reported it.

Since that time, the Asian longhorned beetle has been found in 20 locations in six states, including New York, New Jersey, Massachusetts, Illinois, Ohio and, most recently, South Carolina.

“ALB likely arrived hidden in untreated wood packaging material like pallets and crates from China or Korea, before we had international standards for treating this material to prevent the spread of insects,” said USDA’s Asian longhorned beetle national policy manager Paul Chaloux. “The beetle feeds on numerous hardwood species, especially maple, but also ash, birch, elm, poplar and willow, among others.”

To date, USDA’s Animal and Plant Health Inspection Service has been successful in eradicating the beetle from all but four locations in the U.S.

However, eradication has both financial and environmental costs. According to the USDA, over $750 million has been spent on the Asian longhorned beetle eradication program in the last 22 years, and at least 180,000 trees have been removed from infested neighborhoods and counties.