Forest officials watch for invasive beetles

Posted April 29, 2009, at 7:14 p.m.

BELFAST, Maine — What’s black and white — and feared all over?

The Asian longhorned beetle, an invasive insect from China that probably entered this country through untreated packing crates and likes to eat healthy trees, including the sugar maple.

While the large, white-spotted beetle is not yet known to be in Maine, forest experts are worried that if the eggs slip in through a load of firewood, it could wreak havoc on the state’s forests. The beetle could cripple Maine’s maple syrup and hardwood industries and have a detrimental effect on tourism, experts warn.

The beetles eat the tree’s cambian layer, right under the bark. Then they bore into the heartwood, which destroys the tree’s value, according to Charlene Donohue, an entomologist with the Maine Forest Service.

“We take it as a serious threat,” Donohue said. “It’s an insect that you can slow down and probably keep under some kind of control if you know it’s there.”

That’s exactly what didn’t happen in Worcester, Mass., where officials estimate the Asian longhorned beetle infestation went on for at least a dozen years before anyone realized it was happening. Starting last August, authorities have taken extreme action to try to halt the hungry beetles, including cutting down about 20,000 trees in a 2-square-mile area and implementing a 64-square-mile “quarantine zone” around the infestation.

This has changed the look of the formerly tree-lined streets of the city, Donohue said. She went to Worcester last week as part of a Maine task force charged with finding out how to survey for the beetles, and so did Thomas Hoerth, the city arborist for Bath.

“This had a huge, huge impact on neighborhoods,” he said. “There are some areas that are virtually clear-cut.”

Before the Worcester infestation was discovered, the beetle left its mark on places including Brooklyn, N.Y., Chicago, New Jersey and Toronto. An aggressive campaign to halt the beetle’s spread in Chicago has met with success, according to Donohue.

“They cut down infested trees and potential hosts, and they got rid of it,” she said.

While the threat of a beetle infestation in Maine is severe, it’s not as serious as Dutch elm disease, according to Donohue. The European elm bark beetle spread the Dutch elm fungus, and by the 1970s, as many as 95 percent of American elms had died.

“We won’t lose a species, but it certainly will stress the forest and kill trees,” she said.

Forester and arborist Didier Bonner-Ganter of Belfast has put up posters urging people not to move piles of firewood.

“The biggest thing is awareness,” he said. “Curtailing something at the onset is the only reasonable thing you can do. Once trees become infested, in many cases it’s cost-prohibitive and almost impossible to get rid of.”

Forest Service officials are working with campgrounds to encourage people to leave their firewood at home and “burn it where you buy it.”

“We have all brought firewood when we go camping,” Donohue said. “In a changing world and a global economy, we can’t do it any more.”

The three tree experts stressed the importance of having an educated public keep an eye on the state’s trees and report any signs of the beetle to the Maine Forest Service. If the Forest Service finds the beetle, they will destroy the tree, but the alternative is much worse, Donohue said.

“If you don’t call us, your tree will die anyway,” she warned. “Not only will your tree die, but lots of other ones will, too. It’s tough, but if you can get the beetle soon enough, you can eradicate it.”

For more information, call the Maine Forest Service at 287-2431, or go to www.maine.gov/doc/mfs.

Asian longhorned beetle information

• The beetles are up to 1½-inches long, shiny black with irregular white spots and long, black-and-white banded antennae.

• They look similar to a native beetle, the white-spotted sawyer, which is more of a “bronzy” black and feeds on dead and dying conifers.

• When adult longhorned beetles exit a tree, they leave smooth, round, dime-size holes that a pencil could enter.

• An infested tree will have sawdustlike material, called frass, on the ground around the trunk or on oozing sap.

• Infested trees run foamy sap out of holes.

• Leaves of an infested tree will turn orange and red in summer.

• The beetles are active from early summer through midfall and do not attack oaks or conifers.

• It is known as “starry night” beetle in China.

Information from Bath City Arborist Thomas Hoerth and the University of Vermont Web site, www.uvm.edu/albeetle.

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