A legend tells the tale of a comet that passed near the earth long ago. As the tail of the comet swept by, millions of tiny pieces broke off and fell to the ground. These celestial bodies came to life as beautiful beetles. The Chinese call Anoplophora glabripennis the starry sky beetle because of its spectacular markings, starbursts of white set in a field of jet black. It is also known as a longhorned beetle due to its remarkably long antennae common to beetles in the family Cerambycidae.
During spring and summer, adult beetles eat tender tissue in the canopies of trees. They mate and then return to the trunk and large branches where they use powerful jaws to chew ragged “egg-niches” in the bark. Once the egg niche has been made, the lady turns around and deposits eggs in the hole. Eggs hatch into larvae called roundheaded borers. The name describes the round shape of their body in cross section. The larvae are angels of death as they bore through the life-giving cambium and vascular tissues of the tree. Larvae may take more than a year to develop under the bark. After feeding, larvae pupate under in the wood and later emerge through large round exit holes in the bark. During this time, serious structural damage occurs as the borers kill tissues and drill large galleries through the wood.
Infested trees spew sawdust as larvae eject material from their galleries. Large amounts of dieback in the canopy and death are other symptoms of infestations. These symptoms resemble those of other deadly agents that develop in the woody tissues of plants like the emerald ash borer and other roundheaded borers we met in previous episodes of Bug of the Week. In its native range of Japan, Korea, and China Anoplophora glabripennis attacks many kinds of deciduous trees including willows, poplars, elms, and fruit trees. In China it has a preference for trees under
severe stress that are dying or already dead. In the United States, maple, elm, chestnut, and willow are on the preferred food menu.
History of Asian longhorned beetles
Asian longhorned beetle was first detected in the United States in Greenpoint, Brooklyn, in 1996 by a landlord who thought local pranksters were drilling holes in the maple trees on his properties. An inspector for the local parks and recreation department soon found a large black and white beetle that was subsequently identified as Asian longhorned beetle by Dr. Richard Hoebeke of Cornell University. How did the Asian longhorned beetle get here? It probably arrived in wooden packing material used to crate products manufactured in Asia. Packing material used for crates is often low grade lumber. Lumber used for crates may contain larvae of wood-boring beetles like Asian longhorned beetles. Unfortunately, only a small proportion of crates are inspected and opportunities abound for stowaways to slip through foreign ports and arrive at warehouses in this country. Since the first detection in Asian longhorned beetle in Brooklyn, New York infestations of the beetle were found in several other boroughs of New York City, in Amityville and Islip on Long Island, in several cites in New Jersey, in Chicago and its suburbs, and in the Toronto-Vaughn area of Canada. As part of a quarantine and eradication program for this pest, the United States Department of Agriculture spent million of dollars removing thousands of infested trees and potential hosts for this pest in three states. More than 30,000 trees have been treated with insecticides in an effort to stem the spread of Asian longhorned beetle in the past two years. It is estimated that if this pest were to become widely established in this country and left unchecked the impact in our urban forests would be a loss of 34.9% of total tree canopy cover, well over one billion trees valued at more than $669 billion.
Efforts to control the species
What can be done to help stop this threat? As cities develop plans to plant trees along streets and parks, they should consider the composition of the existing tree community. If a city is already well stocked with trees such as maple, elm, and ash that are vulnerable to pests such as Asian longhorned beetle and emerald ash borer, alternative species should be considered. Lists of replacement trees for areas infested with Asian longhorned beetle have been developed. Many infestations of deadly exotic borers have been discovered by curious and observant citizens who reported their findings to authorities. Learn what these exotic invasive pests look like and learn how to recognize their damage. If you suspect your trees are infested by these pests, report your concerns immediately to your state Department of Agriculture or Cooperative Extension.
We thank Dr. Richard Hoebeke for providing the inspiration and specimens for this Bug of the Week. For more information, please visit the following web sites.