Asian longhorned beetle, Anoplophora glabripennis, is a major pest of maples and other hardwoods in China and Korea. It was discovered in Brooklyn, New York in 1996, with subsequent detections in the Chicago area in 1998 and in northern New Jersey in 2002. The pest was found in Austria in 2001, and in 2003 additional infestations were discovered in Toronto, Ontario and in Montpellier, France. Adult beetles have also been found inside warehouses in a number of locations around the country, but have not been found outdoors at these sites. The insect is believed to have entered North America inside wood packing materials used in the cargo industry, and it was likely introduced several times. All infestations are believed to predate regulations that require treatment of wood packing materials to eliminate hitchhiking insects and fungi.
Asian longhorned beetle is a serious threat to North American forests because of the number of species it can infest and its ability to attack healthy trees. The preferred hosts are maples (Norway, sugar, silver, and red), but the insect has also been found to attack other species such as birch, horse chestnut, poplar, willow, elm, ash, and black locust. Tunneling by the larvae causes branch death and canopy dieback, and sufficient tunneling can girdle a tree and kill it. If the insect became established and spread throughout much of North America, there would be serious environmental and economic impacts, primarily to maple forests and industries that use maple.
Asian longhorned beetle belongs to a Family of beetles known as 'longhorns' or 'longhorned beetles' because of the adults' long antennae. The adults are about 1 - 1.5" long, shiny black with white spots, and have banded black and white antennae. Several native beetles found in Wisconsin have a similar appearance, so specimens should be forwarded to experts for identification.
Adult beetles emerge from infested trees during the summer and are present from July through September. They may remain on the tree they developed in, or they may fly short distances to infest new trees. The eggs are laid on the tree, hatch, and the larvae tunnel beneath the bark to feed in the phloem. Older larvae will burrow deeper into the wood. The following summer, adults will emerge by chewing a ½" diameter exit hole through the bark. Other symptoms of infestation include canopy dieback, darkened pits chewed into the bark where the female laid an egg, oozing sap at these pits (created by the tunneling larvae), and small 'sawdust' piles created by the tunneling adults.
Since the discovery of Asian longhorned beetle in 1996, well over $100 million has been spent in an attempt to find this insect and eradicate it from North America. Detection and control of the pest is labor intensive, as trees must be carefully examined for signs of infestation. Since the insect remains hidden beneath the bark for most of its life cycle, the only practical way to eliminate it is to cut down infested trees and chip or burn them. Nearby trees may also be infested but signs of the insect are missed, so these trees are typically removed and destroyed, too. To date, thousands of trees have been removed in an attempt to eradicate the insect wherever it has been found. Infested areas are also quarantined to prevent the movement of potentially infested wood, nursery stock, firewood or other articles that could contain the insect.
Asian longhorned beetle has not been found infesting trees in Wisconsin, and the best way to manage the insect is to eliminate it from North America. Regulations have been changed to require that wood packing materials be free of bark and treated to kill any insects in the wood. Cargo and shipping materials can be inspected in their country of origin and upon arrival in North America so that the pest is not reintroduced. In addition, quarantines are in place in the infested areas, to stop the movement of potentially infested material into uninfested areas such as Wisconsin.