Search for indicators of invasive Asian longhorned beetle



August is tree control month, and the U.S. Department of Agriculture urges the public to search for and report any signs of the Asian hardwood beetle, an invasive pest not native to Michigan that could harm the state’s environment and economy.

The Michigan Departments of Agriculture and Rural Development; Environment, Great Lakes and Energy; and Natural Resources are joining the USDA asking people to take just 10 minutes this month to check trees near homes for the beetle or any signs of damage it is causing.

In late summer and early fall, adult Asian hardwood beetles drill perfectly round, 3/8-inch holes to emerge from tree trunks and branches, where they spend their larval stage chewing through the heartwood. After a short mating period, female beetles chew oval recesses in trunks or branches to lay eggs. Sometimes a material can be seen at or below the exit holes that resembles wood chips or comes from cracks in the bark of an infested tree.

Asian longhorn beetle in the USA
The Asian longhorn beetle was first discovered in the United States in 1996 when a resident of Brooklyn, New York noticed and reported a large, black beetle with irregular white spots and antennae banded in black and white. Since then, the invasive beetle has been found in 20 locations in six states, including New York, New Jersey, Massachusetts, Illinois, Ohio, and most recently South Carolina.

Asian hardwood beetles likely arrived tucked away in untreated wooden packaging materials such as pallets and boxes before international standards were developed for treating these materials to prevent the spread of insects.

Since adult beetles only fly short distances, it is likely that human movement of infested logs, firewood, or other wood products contributed to the spread of the Asian longhorn beetle in the United States

To date, the USDA Animal and Phytosanitary Inspection Service has been successful in exterminating the beetle in all but four locations in the United States. However, extinction has both financial and environmental costs. Over the past 23 years, over $ 750 million has been spent on the Asian longhorn beetle eradication program and at least 180,000 trees have been removed from infested areas, according to the USDA.

You can help

The beetle has not been detected in Michigan, but detecting early signs of infestation can prevent widespread damage to the state’s forest resources, urban landscape, and maple syrup production.

“We are asking the public for help in finding the Asian longhorn beetle and the tree damage it has caused, because the sooner we know where the insect is, the sooner we can stop its spread,” said Josie Ryan, APHIS National Operations Manager for the ALB eradication program. “Just last year, a South Carolina homeowner reported finding a beetle in his yard.

Search for signs
Whenever you’re outdoors this month, take the time to look for signs of the Asian hardwood beetle in the trees around you, including:

Round exit holes about the diameter of a pencil in tree trunks and branches.
Flat, oval or round scars in the bark where the adult beetle chewed an egg.
Material that looks like wood chips lying on the ground around the tree or in the branches.
Dead branches or branches that fall from an otherwise healthy looking tree.

Find the beetle

Adult Asian longhorn beetles are strikingly large, ranging from 3/4 to 1 1/2 inches in length without their long antennae. The beetles are glossy black, with random white spots or spots, and their antennae have alternating black and white segments. They have six legs that can be black or partially blue, with the blue tint sometimes reaching down to their feet.

Watch out for doppelgangers
Several beetles and beetles native to Michigan are often confused with the Asian longhorn beetle.

The white spotted pine saw has a characteristic white spot below its head – between its wings – and is brownish in color.
The poplar borer is roughly the same size as the Asian longhorn beetle and is also black and white, but has a pattern of individual, wide black stripes on each wing and its antennae are all dark.
The northeastern pine saw grows up to 5 cm long, has very long antennae and is gray in color.
The east-eyed click beetle has distinctive dark circles on the back of the head. It overturns when threatened, then clicks and turns around to get back on its feet.

Anyone watching an Asian longhorn beetle or a tree damaged by it is asked to report it. If possible, trap the beetle in a jar, snap photos, record its location, and report it asap on or contact MDARD at 800-292-3939 or MDA-info @ Michigan. gov.

For more information, see