30-Year Fight Leaves Little Hope in U.S.
BEIJING Fall 1999-- Nearly three years after American scientists began researching ways to fight the Asian long-horned beetle, they have few clues on how to control the scourge that has ravaged thousands of trees in Chicago and New York.
Enormous pressure has been put on scientists to find a way to stop the bug in case the current attempt at eradication--which involves cutting, chipping and burning all infested trees--fails to contain the tree-killing pest.
But scientists in China and the United States, who met last month in Annapolis, Md., to discuss their progress, said even with new details on the bug's behavior, life cycle and mating patterns, they are finding the beetle may be harder to control than previously thought.
Researchers have spent about $2.5 million to date; Sen. Peter Fitzgerald (R-Ill.) is proposing an additional $3.2 million be put toward beetle research and education in next year's federal budget.
"We're getting desperate," said Joseph Cavey, an entomologist with the U.S. Department of Agriculture in Maryland. "It's been a pest in China for 30 years, and despite that there are no convincing traps, attractants or chemical controls. We need something better to eradicate the beetle."
Still, battle plans are being readied in cities such as Chicago, where Ald. Gene Schulter (47th) will meet with USDA officials Monday to discuss a plan to test a pesticide on street trees this year.
The pesticide, called Merit, appeared to be the most effective of five pesticides injected into tree trunks and roots in a 1,000-tree study in northwestern Gansu province in China last summer. The studies tested whether the pesticide spread systemically throughout the trees to kill the adult bugs and the larvae that feed on the wood.
The pesticide did kill the adult bugs. But because it didn't kill many larvae burrowed deep into the wood, officials say the treatment would serve only as possible protection from future beetle attacks.
"Once they bore in, you probably don't have a prayer," said Vic Mastro, whose USDA lab still is analyzing the results.
One USDA researcher, who asked not to be identified, said after only one year of tests it's too soon to try Merit in the United States.
"I am surprised they are going to do this," the researcher said. "I'm not really happy about this."
Mastro cautioned against viewing Merit, manufactured by Bayer Corp., as a "magic bullet" that will save infested Chicago trees from the ax. And he said pressure pushed researchers to field-test the chemical in the United States before they knew the best way to apply it so it kills all of the bugs in a tree.
But he said the five-year study should establish whether Merit can help prevent healthy trees close to known infestations from being infested themselves.
The research in pesticides provides more hope than once-promising studies on pheromones, chemicals released by the bug to attract mates. Finding a way to attract the bugs from the trees is seen as crucial to eradication because it can be difficult to locate an infested tree.
USDA Secretary Dan Glickman announced last summer that his scientists had found a pheromone that might lure Asian long-horned beetles into traps. But in what scientists are now calling an embarrassing setback, the lure had virtually no impact when tested in China.
"We were hoping those compounds would attract insects into traps," said Jeffrey Aldrich, a USDA research entomologist in Maryland involved in the studies. "That did not happen."
Researchers also have dimmed hopes that ultraviolet light could coax beetles from trees. Last summer, David Williams, a research entomologist for the U.S. Forest Service in Pennsylvania, set up lights under trees in South Korea, where the beetle also has been found but in much smaller populations than in China. The lights attracted just one pair of bugs.
"We may be barking up the wrong tree," Williams said.
In studying the beetle's basic traits--which will help determine the best method to control the bug--scientists are finding the beetle might live longer, lay more eggs and fly farther than previously thought.
In a study in a USDA lab in Connecticut using beetles that emerged from logs taken from Chicago last February, entomologist Melody Keena found female beetles laid an average of 68 eggs and lived an average of 73 days--both twice the averages listed in Chinese literature. One beetle lived more than three months and laid 160 eggs. "Under favorable conditions, these beetles could potentially increase in numbers rapidly," Keena said.
The beetle appears to fly farther and faster than previously thought. In China last summer, USDA entomologist Michael Smith observed the beetle traveling more than one-fourth of a mile in a single flight and recorded it moving nearly nine-tenths of a mile over a summer--both distances that indicate infestations can spread quickly.
"This insect flies upwind and downwind," Smith said. "I've seen a few circle trees several times before landing."
A variety of living organisms, including fungus, wasps and other beetles, could slow the beetles down.
Scientists are studying a fungus sold commercially to orchards in Japan to fight citrus borers. It was found to kill Asian long-horned beetles in lab tests last summer. Similar to mold on a piece of bread, the fungus overtakes the beetle and kills it.
But any biological control mechanism needs to be researched over several years and would be used only after scientists conclude there would be no adverse impact on the rest of the ecosystem.
A positive development has been the surprisingly collaborative research agreements forged between U.S. and Chinese scientists despite the continued tension in U.S.-China trade relations.
"We have had excellent cooperation with China in terms of research," an official with the U.S. Embassy in Beijing said.
That is crucial to continuing research because only a handful of quarantine laboratories in the United States permit research on live beetles. And raising one beetle at those labs costs $57, Keena estimates, compared with about $5 to raise thousands of other insects.
While scientists have their hands full with the known infestations in New York and Chicago, they might not have to face completely new outbreaks anytime soon. Since December 1998, when the United States began requiring that all wood crates and pallets shipped from China be heat-treated and certified, only two Asian long-horned beetles have been found in Chinese cargo by border inspectors. About 30 bugs had been found in the few years before that.
And despite denials from China at the time that the bug came to Chicago's Ravenswood neighborhood via Chinese cargo shipped to a local hardware importer, the Chinese have given the University of Illinois at Urbana-Champaign hundreds of dead beetles for genetic tests. Entomologist Larry Hanks will compare the Chinese bugs' genetic makeup with others found in Chicago and New York. If the bugs match, then the dispute over the beetles' origin will be over.
Although Chicago city officials believe they have wiped out 95 percent of the Asian long-horned beetle population here, they know the battle is far from over.
Within the last few weeks, city crews found 18 more infested trees. "If they aren't found, it will begin the process all over," said Terry Levin, spokesman for the Department of Streets and Sanitation.
Report damage
* Asian long-horned beetle: Black with white spots, 1-inch long with long, striped antennae.
* Damage: Beetles chew holes to lay eggs. Larvae bore into trees during winter and emerge in summer.
* To report beetles or damage: City Beetle Command, ( 312) 742-3385.
* For suburbs, the state Agriculture Department, (847) 294-4343, or
(800) 641-3934.
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