Asian beetle bores into Brooklyn's maple trees Foresters fear that insect could become a nationwide problem

November 17, 1996|By BOSTON GLOBE

NEW YORK - An Asian beetle that found its way to Brooklyn, N.Y., is devouring maple trees there, and some foresters fear that the insects will spread, ravaging maples - and dimming fall foliage displays - across the country.

So far, the damage has been limited to some 200 Norway maples in Brooklyn's Greenpoint neighborhood, and it's not clear that the invader, an Asian long-horned beetle new to this country, will try to expand its terrritory.

But given the beetle's hardiness and apparent lack of natural predators in North America, some tree specialists fear the worst: a killer that could spread from a single site, the way Dutch elm blight spread from Cleveland in the early 1930s, to devastate a species nationwide over many years.

The impact on New England could be severe. Nearly 30 percent of the large trees in Massachusetts and Vermont are maples, which have proven to be the favorite meal of the Asian beetle in Brooklyn, according to U.S .Forest Service studies.

Maple syrup production is at least a $17 million-a-year industry for New England, according to 1994 statistics, and leaf-peeping season accounts for up to a quarter of the area's tourism.

'I get the shivers'

"Every time I hear about one more introduced pest that's starting to spread, I get the shivers," said John O'Keefe of the Harvard Forest in Petersham.

New York's parks commissioner, Henry Stern, said, "It's quite serious, and we're quite concerned."

Experts from the U.S. Department of Agriculture have been in Brooklyn to survey damage to Norway maples along sidewalks and to consider strategies to control the beetles. They may use insecticides or injections of fungi that kill the beetles or conduct mass felling of stricken trees.

The beetle is an inch-long black insect with long antennae and dramatic white spots that Stern said "would look rather festive if it weren't so deadly." It is native to Japan, Korea and southern China, and New York officials think the beetle arrived in Brooklyn on a shipping container or load of wood.

It was spotted in August by a Brooklyn landlord and amateur horticulturalist who was stunned to see drill-like holes and piles of sawdust at the base of many Norway maples and horse chestnuts along his street. He reported it to city officials

Entomologist Allan Samuelson of the University of Honolulu's Bernice P. Bishop Museum, which maintains one of the world's largest collections of Asian beetles, confirmed that the predator was the long-horned beetle, Anoplophora glabripennis.

The beetle is slowly killing maples in Brooklyn by boring finger-sized holes into the trunks. In late summer, female beetles lay eggs in the holes, and as the larvae hatch they bore into the heartwood for food and winter shelter.

Come spring, the adult beetles bore their way back out, leaving trees riddled with gaping, sappy holes and susceptible to other parasites and weather damage, according to Cornell University entomologist E. Richard Hoebeke. The beetles are not harmful to people.

A fairly broad diet

Some specialists doubt there is any reason to panic. "I'm not saying it's not going to be a serious pest, but it may get onto other hardwoods, as well," and not attack specifically maples, Samuelson said. "This beetle has a fairly broad diet. They often attack trees that are weak, or they just pick a branch on a tree. In many cases they do some good. They help prune the tree," Samuelson said.

Nina Bassuk, a Cornell professor of floriculture and ornamental horticulture, said, "It's potentially very worrying, but it's really premature to say what's going to happen."

One possibility, Bassuk said, is that the beetle larvae might not survive winter in New York, which is generally much harsher than the beetle's home habitat in Asia.

But Vic Mastro, a pest control specialist with the Department of Agriculture station on Cape Cod, said: "Given the host range of this beetle and where it occurs in Asia, and given the hosts [trees] that are present here in North America, it could occur anywhere in the United States."

It would most likely spread on trucks and cars.

Sugar maples are attacked by a predator called the sugar maple borer, according to Kevin Evans, Dartmouth College's forester. But it tends to cause only minor damage that reduces the saw-log value of the wood, and it never strikes more than 20 to 30 percent of the trees in a stand, Evans said.

If it spreads, the Asian beetle is of particular concern not just for syrup farmers but for New England tourism generally, because "often the peak foliage is tied in with maples," O'Keefe said. "The colors that people come to this area for are really the maples."

Red maples, found in hills as well as swampy areas, produce dramatic reds, while the sugar maple, which prefers higher elevations, generates vivid golden-yellow and orange-red foliage.

Vermont officials estimate they make a quarter of all their tourist income during September and October's "leaf-peeping" season.

Pub Date: 11/17/96

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