Big Apple Has A Worm – The Asian Long-horned Beetle

One of the first U.S. sightings of the Asian long-horned beetle was in 1992 in Loudonville, Ohio, according to an article in the January-February 2000 issue of Audubon magazine. These beetles arrived in solid-wood packing materials in a shipment from China. Larvae of the beetles were camped inside the untreated lumber nourishing themselves on the wood. The larvae later pupated and metamorphosed into adult beetles and bored their way out into the spotlight for the first time in the U.S. Following its initial U.S. emergence, the beetle did not raise much concern until four years later when it stepped into the spotlight again to remain there indefinitely.

According to Audubon, the 1996 discovery in Brooklyn prompted the Animal and Plant Health Inspection Service to carefully monitor the city and surrounding areas for presence of the pest. Inspectors soon found the beetle in Amityville, New York, which is about 30 miles east of Brooklyn. In December 1996 a state quarantine was ordered, followed by a federal quarantine in early 1997. The quarantines restricted movement of wood and related agricultural products from designated areas.

Surprisingly in 1997, the adult beetles did not emerge until late July, which is much later than the normal May hatching date. Despite the late emergence, scientists weren’t overly optimistic about the possible disappearance of the beetle. "We were hoping that we wouldn’t find it, but we figured we’d probably find it. And we did," said E. Richard Hoebeke, an entomologist at Cornell University and associate curator of the Cornell Insect Collection.

The beetle was discovered in Queens and Lindenhurst, New York, later in 1998, according to Audubon. These two discoveries were near the edge of and even outside of the created quarantine lines. In July of that same year the beetle showed up 900 miles away in Ravenswood, Ill., a Chicago suburb. Here, scientists found more than 50 infested trees, including Norway maples, silver maples, box elders, elms and horse chestnuts. By August, 300 trees were infested in Ravenswood, and infestations were also discovered in DuPage County, which is 20 miles to the Southwest of Ravenswood, according to Audubon. The Chicago area discoveries prompted similar quarantines to the ones imposed in New York. Once again, cargo shipments from China were blamed as the likely mode of transportation for the pest.

During the summer of 1999 the beetle was discovered in three sites outside the Chicago quarantine area. The pest was also spotted in three new sites in New York, including an infestation four blocks from Central Park, according to Audubon. Scientists and the government are waiting in anticipation of the upcoming hatching of the beetles to determine how widespread they are this year.

A Destructive Life Cycle
According to the Audubon article, "After mating in early summer, a female finds a secure spot on a branch and chews a hole in the bark with her strong mandibles. She then turns around and deposits a single white egg, 1/5- to 1/4- inch in length, and covers it with a cement like substance … Over the course of her 40- to 60-day lifetime, a female can lay as many as 40 eggs. After a week or two, the egg hatches and the larva gnaws inward, penetrating the inner bark and riddling it with tunnels." The article also states that larvae grow to two inches or longer and can bore several feet before pupating. The adults then chew out an exit hole after winter to start the destructive cycle again. Adult beetles can usually be found from May to October.

The Asian long-horned beetle is native to Japan, Korea and the southern sections of China and has no known natural enemy in North America. The larvae of the beetles cut through the sapwood of trees, which prevents fluids from reaching the leaves. This malnutrition causes branches to weaken and die. Severe infestations may kill a tree, according to Audubon, but that may take years of tunneling. However, damaged trees that do not die are useless for lumber.

About the only use a beetle-damaged tree has is for firewood, which is exactly what officials do to fight the spread of the pest. However, the trees are not sold as firewood. The entire trees, including the stumps, are instead cut, chipped and burned immediately to kill the larvae inside. Burning has been the most effective way to eliminate the pest, especially because of the beetle’s low dispersal rate. Joe Cavey, an entomologist with the U.S. Department of Agriculture/Animal and Plant Health Inspection Service, based in Riverdale, Md., said, "It doesn't even fly a mile from its source. If we keep up our efforts, we’ll have a good shot at containing it. It’s the best shot at eradicating anything like this in my 21 years of service."

Because most pesticides don’t penetrate tree bark and the beetles spend several months inside trees during their larval stage, pesticides used thus far have been fairly ineffective at controlling the pest. However, this season field tests are being conducted in Chicago of the systemic pesticide Merit, according to Win McLane, a USDA official. Merit is to be tried on 240 non-infested trees – in four different areas of 60 trees each – in Ravenswood. In each area of 60 uninfected trees, Merit will be injected into the soil around 15 trees and injected into the trunks of 15 others. The remaining 30 trees will be controls to compare their experience to that of the treated trees. Officials hope Merit might be able to protect trees that haven’t been attacked by the beetle yet. Similar tests are being planned for New York City and Long Island. "Officials are optimistic these field tests will provide an alternative to tree removal in the battle against this pest," the USDA said in a statement.

Last year, officials removed 4,300 Asian long-horned beetle infested trees in and around New York City and another 1,200 trees in the Chicago area. A majority of these trees are maples because of the tree’s popularity as a shade tree in northeastern cities and its popularity among the beetles themselves. Nina Bassuk, Cornell professor of floriculture and ornamental horticulture, took a survey of Brooklyn trees in 1990. She found that 27 percent of the 110,000 street trees in Brooklyn are Norway maples – the trees the beetle attacks most often. "I think this could be devastating for the city," Bassuk said. "After all, the Norway maple is the most widely planted shade tree in New York State."

Lawrence Hanks, a long-horned beetle expert at the University of Illinois, was quoted in the Audubon article, stating, "If it becomes established, the Asian long-horned beetle could wipe out a quarter of the shade trees now growing in U.S. cities."

Several steps are currently in place to promote education of the Asian long-horned beetle to customs agents and the general public as well. Hoebeke and Cavey are currently preparing a detailed description and diagnosis of the larval stage of the Asian long-horned beetle for an upcoming issue of The Coleopterists Bulletin. Also, the USDA’s Agricultural Research Service (ARS) has awarded Hoebeke a $50,000 grant to help eradicate the beetle. Hoebeke will receive the grant to research and help produce a comprehensive, illustrated handbook for the identification of the beetles’ genus group. The handbook, to be written in collaboration with ARS entomologist Steven Lingafelter, will be used by authorities to help stop infestation of the beetle at U.S. borders. Public education includes a USDA-produced one-minute film segment about the beetle, according to Audubon. The segment, which airs in the New York area, is narrated by America’s Most Wanted host John Walsh.

The New York beetle infestations may threaten the state’s maple industry and autumn-foliage tourism industry. However, spread of the beetle could also threaten the U.S. lumber industry, especially if it finds high lumber producing areas such as the Pacific Northwest. "If we are importing products from China or Asia and those products come shipped with wood – such as crates, blocking, pallets, even large spools for wire – we’ve got to be concerned," said Hoebeke. "This really should become a national concern."

The potential impact of the miniscule Asian long-horned beetle is enormous. Economists estimate up to $138 billion in damage to the U.S. economy if the beetle were to spread nationwide, according to a Reuters news release. "If this pest moves into the hardwood forests of the United States, the nursery and forest products industries could experience severe economic losses," the USDA said in a Federal Register notice.