Beetle From China Threatening U.S. Hardwood Trees

By Cheryl Lyn Dybas Special to The Washington Post Monday, July 9, 2001; Page A07

For a century and a half, a mighty elm guarded Montauk Highway in Amityville, N.Y. Generations of Amityville residents and visitors paid homage to the grand old tree on their way to work, school, and points beyond.

But last May, the tree was felled by euthanizers with little alternative. A latter-day "Amityville Horror" – the Asian long-horned beetle – had bored into the inner bark of the tree, leaving the elm with gaping wounds.

Lethal to a wide range of tree species, Asian long-horned beetles "threaten everything from backyard, park and city-street trees, to the maple syrup industry, to tourism in fall-foliage regions," said Joe Cavey, a beetle expert at the Agriculture Department's Animal and Plant Health Inspection Service (APHIS) in Riverdale.

The invaders are native to China and other parts of Asia. In China, they're widespread pests, particularly in poplar tree plantations. The insects are believed to have entered the United States in wooden crates used to ship products from China. Thus far, they've infected only a few parts of the country: the New York City-Long Island area and the environs of Chicago.

"People living anywhere shipments from China arrive in wooden crates – Newark, Philadelphia, Cincinnati, Washington – should be on the lookout," Cavey said. "The sheer volume of imports from China, and the fact that infested wood is not always in plain sight, make it almost impossible to keep the bugs out."

The beetles have 1-inch-long, bullet-shaped black bodies with white spots. Their 2-inch-long black antennae have white rings. Adults lay eggs in tree bark in spring and fall. The inch-long white larvae bore into trees, creating holes and tunnels that can kill mature trees in less than a year.

"Heavy ooze will also flow from tree wounds made by the larvae," said Richard Hoebeke of Cornell University in Ithaca, N.Y., who identified the first Asian long-horned beetle in the United States.

The insects prefer sugar and Norway maples, but they'll also attack apple, cherry, elm, horse chestnut, locust, mulberry, pear, poplar and willow trees. "Hardwood trees in the northern tier states seem to be 'where it's at' for Asian long-horned beetles, at least at this point," Hoebeke said. "In fact, this beetle well may be the single biggest threat facing the nation's hardwood forests. Asian long-horned beetles could be the 21st century's gypsy moths."

Should the beetle spread across the country, estimates predict nearly $138 billion in damage to the U.S. economy.

Although the beetles first turned up in Amityville, they later were found in Queens. Then a few years ago, a Chicago resident trying to identify beetles crawling out of his firewood alerted scientists that the invaders had reached a new urban center. No one knows exactly how the beetles made their way to Chicago.

"Although these beetles don't move far from their 'host trees,' " said Mike Stefan, an APHIS scientist in charge of the Asian long-horned beetle response program, "transporting infested firewood and branches may accidentally move them to new locales. Quarantines therefore have been set up in areas identified as having beetles, and infested trees in these places are being destroyed."

In quarantined locations, regulations prohibit the movement out of the area of firewood, green lumber and other wood materials – living, dead, cut or fallen – including nursery stock, logs, stumps, roots, branches and debris of a half-inch or more. To help prevent more beetles from entering the country, the federal government has implemented new rules for treating wooden crates from China. Solid wood packing materials from China must be heat-treated, fumigated or laced with preservatives before a shipment can enter the country.

"Unfortunately," Stefan said, "once the beetles are here, the only reliable way we now have of eradicating them is to cut down the trees in which they've taken up residence. But not everyone is in favor of this idea. You'd be amazed at how attached people can become to one tree, or group of trees, but we tell them it's the only way to save other trees in their neighborhood, or city."

In Amityville, for example, more than 1,500 trees have been felled since discovery of the beetle there in 1996. Many of those have been on private property, although some have been in public areas. About one-third of the trees have been replaced. The Amityville beetle war's estimated to-date cost exceeds $1 million. Elsewhere, more than 5,500 trees were destroyed in 1999 alone in the New York City and Chicago areas.

In early 2000, the Clinton administration vowed to step up a nationwide offensive against the beetles. Last spring, APHIS scientists began testing an insecticide, imidacloprid, that's injected into the soil surrounding hardwood trees, or directly into the trees themselves.

Uninfested trees within one-eighth of a mile of infested tree locations were being treated this spring in the quarantined areas of Chicago and New York. Tree species targeted include maple, birch, horse chestnut, willow, elm and ash. The insecticide is injected into the base of the trees. It then moves upward into the trunk, stems, twigs and foliage.

"The intent is to deliver the pesticide quickly from the site of application to active tree growth areas, where the beetles would be expected to feed and lay eggs," Stefan said.

Insecticide treatments – and tree removal, where that's needed – must be done before early summer, when beetle larvae mature and emerge to infect other trees. How far Asian long-horned beetles can fly is a matter of debate; some scientists believe that the size and weight of the beetles limit them to a range of about 50 yards, but new research indicates that the beetles may be able to fly almost 500 yards to reach another tree, if necessary.

The effectiveness of imidacloprid on already infested trees is unknown. "We're planning to monitor results to see if this treatment can help trees that already have beetles," Stefan said. "However, in the current scenario, if a tree is found to be infested before application of the treatment, or during post-treatment inspections, it will be destroyed. For now, we don't have much choice."

APHIS is also concerned about environmental effects of pesticides, added Cavey. "The precise placement of imidacloprid treatments, and ways we have developed of securing the area around trees undergoing treatment, preclude many potentially adverse effects. The environment is only minimally affected, because imidacloprid residue is restricted to the tree itself."

Kim French, a resident of DuPage County, Ill., which falls within one of the current quarantine areas in the Chicago region, said that "if even one tree in my yard or neighborhood can be saved, let alone most of them in my county, we need to explore whatever options we have of getting rid of these beetles. The beetles don't belong here. The rows upon rows of tall trees that have lined my street for decades do."

© 2001 The Washington Post Company

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