Researchers Developing Easier, Cheaper Ways to Catch Beetles
Beetles
Worcester Telegram and Gazette
Rachel Kolokoff
Boston University Washington News Service
Nov. 26, 2008
WASHINGTON – A costly battle is now being waged over the future of Maples and other hardwood trees in the Northeast. The enemy in that fight is a small, black and white-speckled beetle that stowed away inside wooden crates on a ship from China and emerged with the potential to become one of the most destructive insect species the United States has ever seen.
The Asian Longhorned Beetle was first discovered in New York in 1996, and since then has been found in Illinois, New Jersey and now in Worcester, the fourth infestation site in the U.S.
Spotted in the Kendrick Field section of Worcester in August, it has probably been in the city for at least seven or eight years, according to Michael T. Smith, a U.S. Department of Agriculture researcher who has studied the beetle in China, its native land. Since then department officials have begun looking for infested trees within a 62-mile area including the city and parts of Boylston, Holden, Shrewsbury and West Boylston.
When the beetle finds a potential host tree it chews a depression in the bark, lays an individual egg in that depression and then packs it down. When the larvae hatch, they bore into the tree and stay there, living off the wood and nutrients while they mature.
According to Mr. Smith, an infested tree can look normal for three to four years while the beetles are chewing its insides, working their way towards the outer bark. But eventually, if enough beetles have infested the tree, they girdle it, cut off its water flow and leave it to die. Chewing their way out of the tree, the grown beetles leave behind dime-sized holes, undeniable evidence of their presence, and move on.
Federal, state and city governments are spending hundreds of millions of dollars on programs to find and eradicate the tree-killing beetle. The task is extremely costly and time-consuming, but more efficient weapons against the pest may soon be on the way.
Mr. Smith, part of the agriculture department’s Beneficial Insects Introduction Research Unit in Delaware, is coming to Worcester in December to work in the field and try to develop faster, cheaper ways to detect and control the beetle.
The cost for Worcester’s program is growing as surveyors find more infested trees, according to U.S. Rep. James P. McGovern.
The total cost cannot be specified until surveyors determine the full extent of the infestation, but Mr. McGovern said it is expected to exceed $30 million for the first year.
Suzanne Bond, spokeswoman for the inspection program in Worcester, said the department has agreed to cover the costs for the first year of eradication efforts. But in the following years, costs will probably be divided among the federal, state and city governments, as they have been in Illinois, New Jersey and New York.
“Moving forward, cost-sharing relationships are basically part of the process,” Ms. Bond said.
Mr. McGovern said Worcester has already invested a lot of manpower in the beetle program and cannot afford to spend more.
“These are hard economic times,” he said, “and we shouldn’t have to pay for this.”
In terms of cost, it is best to intercept the beetle early on, according to Mr. Smith. Once the population grows past a certain point, it is no longer possible to eliminate it; at that point, regulating its growth becomes the goal.
“The Northeast is very worried,” Mr. Smith said.
In Worcester, the beetle is current inhabiting urban areas on the edge of forest, he said. If the beetle enters the forest, it will be much harder to contain.
Mr. Smith said the infestation in Worcester is large enough to allow him and his colleagues time to complete some fieldwork before workers chop down and grind up all the infested trees.
“There’s a lot we can learn that’s specific to the U.S. by getting our hands dirty up there,” he said.
Ms. Bond said efforts to survey the regulated area will continue to be ongoing throughout the winter.
Mr. Smith said the detection methods he is developing could save time and money for surveyors like those in Worcester by allowing them to determine more quickly which trees are infested.
The faster that workers can detect infested trees, the faster that they can eradicate the beetle, whose destruction of Northeastern trees and forests could potentially cause billions of dollars in damage to the lumber industry, the maple syrup industry and the tourism industry, which depends on fall colors. Water and air quality could also be affected.
So far, surveyors in Worcester have found more than 3,000 infested trees through the only available method–using their eyes or binoculars to examine trees one by one for markings associated with infestation. Often, they must climb the trees to look for markings in the canopy.
Mr. Smith said those methods are 66 percent effective, meaning that for every 10 infested trees examined, they can miss three or four infested trees.
As one alternative, Mr. Smith is trying to analyze the sound beetles make when they chew wood inside a tree. If he can determine the specific noise the chewing makes, he can detect infestations by touching an acoustic sensor to the tree.
“You can pretty much develop the acoustic signature,” he said, “and the sensor could recognize it, kind of how telephones can recognize your voice.”
Another tool would measure the amount of carbon dioxide in each tree. Because beetles produce carbon dioxide, infested trees would have unusually high levels.
“It’s in its early stages,” Mr. Smith said, “but it has been developed by a company that would use them to detect termites in walls.”
The tool, which looks much like an oversized remote control, has a metal, needle-like probe that would pierce the bark of the tree.
Because the best way to test the tool is in the field, Mr. Smith said, he will probably take it with him when he goes to Worcester in December.
Most of his other fieldwork has been in China, where he has spent two months every summer for the past 11 years.
“That’s the meat of my research,” he said, “because you need to study the beetle in its natural settings.”
In China, Mr. Smith collects species of wasps and brings them to his quarantined Delaware laboratory for study to determine whether wasps that parasitize the beetles could be used to help control infestations.
While in Worcester, Mr. Smith hopes to find native species of wasps that parasitize the beetle. To study the natives, he brings them to his insectary, a small, outdoor breeding house, where he allows them to grow inside large cylinders containing 2-foot log segments.
Standing in the insectary’s narrow, dusty walkways during warmer months, Mr. Smith is completely surrounded by some 500 cylinders, each filled with wood and a species of insect, stacked row-by-row.
Once the wasps develop, he brings them into the quarantined lab and unleashes them on logs infested with beetles, to see if they attack.
After three years of traveling to eastern forests, he has found four native species of wasps that act as the beetle’s natural enemies, he said. One wasp goes inside the tree, lays eggs on the outside of the beetle larvae and stays until the eggs hatch.
“If one of her eggs falls off the surface of that larvae, she’s able to move it back on,” he said. “The parental care is very amazing.”
The larvae grow inside the tree for most of the year and emerge as adults in the spring and summer.
Currently, surveyors can search only for trees infested with larvae and have no way of searching for adult beetles. But Mr. Smith is also developing a lure, an aroma that surveyors can use to attract beetles and determine if an area is infested.
To develop the lure, he is working with scientists to isolate the chemicals found in certain trees that the beetles are naturally attracted to.
Mr. Smith said he was “tickled pink” by the success he had in the lab this year and hopes to have a lure that could be mass-produced sometime soon.
Over every four or five-year period, some 15 exotic insect species are introduced to the United States but only one reproduces enough to become a major pest, according to Mr. Smith.
Many of those species, such as the Asian Longhorned Beetle, enter on foreign ships that dock at U.S. ports of entry.
If port inspectors find insects on board the vessel or in cargo, they box them and mail them to the Smithsonian National Museum of Natural History, where Department of Agriculture researcher Steven Lingafelter, an expert on Asian Longhorned Beetles, works. About 60 specimens arrive each day.
“When I find a specimen while I’m traveling in other countries, he (Lingafelter) is who I send it to if I need it identified,” Mr. Smith said.
Mr. Lingafelter got his job in the museum’s entomology department in 1996, on the same day the beetles were first found in New York, he said.
Mr. Lingafelter has traveled to China, Korea and Japan to study the beetles, and his office shelves are lined with jars of beetle larvae and pupae.
The Asian Longhorn Beetles are his favorite species, he said, in part because they are so colorful.
They come in a variety of shades, including white, yellow, black, orange, aqua and a deep, iridescent green. Each has spots, which are actually patches of densely packed hairs easily seen under a microscope.
“It’s really a beautiful group, for sure,” Mr. Lingafelter said.
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