Be on the lookout for Asian longhorned beetles

Mike Melanson

If the Asian longhorned beetle invades Plymouth County, it could devour tens of thousands of healthy maple, willow and birch trees, officials say.

The beetle first came to the U.S. in 1996 in wood pallets and wood packing materials on Chinese cargo ships. Since then, it has laid waste to more than 40,000 trees across the Northeast and cost more than $269 million in damage.

Deborah Swanson, an educator with the Plymouth County Landscape Nursery and Urban Forestry program, said the Asian longhorned beetle was first found in Massachusetts by a backyard gardener in Worcester last August.

Since then, Worcester has lost 15,400 trees and could lose 7,000 more by the end of the year, she said.

“Unlike some other beetles that attack only stressed trees, this beetle will attack a healthy tree,” Swanson said.

“It really loves all the maples. The sugar maples, the red maples, the Norway maples, it adores; and willows and some other trees,” she said. “Oaks do not seem to be a primary host of this particular beetle.

“But because it can attack some of these sugar maples, red maples, silver maples and living trees, it poses a great threat to our native trees and other trees,” she said.

The Asian longhorned beetle is large, about 3/4-inch to 11/2 inches long. It’s a “dark, patent-leather black” beetle with white spots and large antennas, Swanson said.

“They’re beautiful beetles; destructive, but they’re a beautifully large beetle,” she said.

The Asian longhorned beetle has no known predators in this country. If a tree is infested, it has to be cut down. An insecticide can be applied to other trees to deter infestation, Swanson said.

Adult female and male beetles emerge from June to August and mate. The female beetle chews a round hole in a tree, about three-eighths of an inch deep, and lays her eggs. Larvae bore into the trees, grow and bore their way out the following spring as adult beetles, Swanson said.

“In Plymouth County, we want people to be acutely aware of this particular pest, what it looks like,” she said.

West Bridgewater Forestry Superintendent and Tree Warden Christopher Iannitelli said he and Swanson scouted the town last week, but found no signs of Asian longhorned beetles.

“We’re going to continue to watch it. Crews that are out cutting trees are going to watch it,” Iannitelli said.

“It’s a concern,” he said. “We’re already under stress here. Our oaks are under stress because of the winter moth and the caterpillar issues we’ve had over the last few years.”

The Enterprise