Among America's 'most wanted': hungry beetle
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The USDA, which has spent $213 million fighting the beetle since 1996, is taking a no-holds-barred approach. Any tree where eggs or beetle holes are found is cut down and ground up - and the sawdust burned so no egg or grub escapes. The two infested elms found in Central Park last month were eliminated, the roots ground down to six inches below sidewalk level.Skip to next paragraph
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Beetle battlers have tried more high-tech, less labor-intensive weapons. One early technology developed by scientists at Oak Ridge National Laboratory involved attaching sensors to trees to detect munching beetles inside. But that proved impractical in the field. There's some hope for a fungus that can kill the beetle, but its effective deployment is still being researched.
Down the road, beetle spotters might be able to use new aerial surveillance techniques involving spectral analysis of light to detect defoliation, Mr. Gittleman says. And scientists are still looking for that special mating scent that might be used to lure the beetle into a chemical trap. But unlike other beetles, the ALB hasn't been found to use powerful, long-distance scent detection to find a mate.
So far, smoke jumpers in the trees and insecticide crews on the ground are the best defense.
A cellphone virtually glued to his palm, Dan Puleo, a USDA officer, orchestrates eight crews injecting a mild insecticide into the soil around thousands of potential host trees across Central Park. About a third of its 26,000 trees are potential hosts to ALB, says the Central Park Conservancy, which manages the park.
For a few years, the USDA in New York injected trees directly with insecticide. But that proved too costly, requiring the agency to hire "tree watchers" to keep the public away for hours. A few years ago, the department began injecting insecticide into the soil around the tree.
"This insecticide injection method is really practically our only weapon, other than the smoke jumpers, for defeating the beetle," Mr. Puleo says. It makes the tree deadly to the adult beetle.
Working not far from 86th Street and the Great Lawn section of the park, one of Puleo's beetle-blockade crews is hard at work. Clad in jump suit and green gloves, John Massing moves systematically around the base of a horse chestnut, calling out the tree's diameter and calculating the appropriate amount of insecticide. He then inserts a metal probe into the ground and pumps insecticide from a pressure bottle.
"All trees have intrinsic value as far as I'm concerned," says Mr. Massing. "This park is the gem of the city and one of the best in the country. We've got to defend it."
While some hope the ALB tide has turned, Dr. Hoebeke notes that this beetle battle may be a sign of things to come. Last week he identified the first female Old World woodwasp seen in the eastern US, discovered in a bug trap in Fulton County, N.Y. The species has wiped out up to 80 percent of pine tree species in Australia, New Zealand, South America, and South Africa, and he worries it could spread nationwide, particularly in pine forests in the southern US. "Like the Asian longhorned beetle, we don't have a lot of resources to fight invasives like the Old World woodwasp, but we just don't have any choice but to try."
That spirit has kept Behm, the smoke jumper, coming back every year for the past three years. She lowers herself from the heights, rappelling smoothly down to sidewalk level from the elm's upper reaches she's been clambering over for the past 45 minutes. Ordinarily, smoke jumpers don't like to climb trees, she explains, unless their parachutes get hung up. But this tree-climbing is different.
"These are really big, old-growth trees," she says with sweat glistening on her face. "I've been coming back year after year. I'm just glad they called us in to help save them."
Insects cause millions of dollars of damage. Here's one ranking of the top five pests for hardwood trees:
• Gypsy moth: For the past quarter century, its larvae have defoliated some 1 million acres a year in the eastern United States.
• Emerald ash borer: First detected in 2002, the boring beetle kills millions of ash trees every year.
• Longhorned beetles: These pests, which include the Asian longhorned variety (see story, left), bore deep into trees, weakening and eventually killing the trees they infest.
• Elm bark beetle: The native and European varieties spread the spores of Dutch elm fungus from infested trees to healthy ones.
• Tent caterpillars: The eastern and even more destructive forest caterpillar varieties feast on wild cherry but also attack oaks, maples, and other shade trees. Forest tent caterpillars can strip all leaves from acres of forest.
Source: Steve Nix of About.com