Asian Longhorn Beetle

Order:   Coleoptera
Family:   Cerambycidae

Identification: Longhorn beetles can easily be distinguished from other beetles by their unusually long antennae.  The antennae of most species of Cerambycids extend up to or  past the abdomen.  There is usually a sexual dimorphism between males and females, with males having much longer antennae (see photo).  Additionally, Cerambycids have unusually shaped eyes (like kidney beans) with the antennae originating from around the middle of the eye.  The Asian Longhorn Beetle (ALB), Anoplophora glabripennis, is a large, robust beetle.  The elytra (hardened wings of a beetle) are a shining black with irregular splotches of white.  The antennae are quite striking with bands of black and gray.  The feet and legs are decorated with a pubescent slate blue color.  Since its discovery in Bellingham, we have received many calls of eyewitnesses to this beetle.  However, most have turned out to be the Banded Alder Borer (see photo) which commonly occurs in our area and is not usually a problem.  You can easily distinguish this beetle with ALB by the banded pattern across the elytra and no splotches.  The alder borer is also generally slender as compared to ALB.  Finally, the thorax is usually gray with a large black spot in the center.  Bring in anything that looks similar to these descriptions.

Development & Damage: Wood-boring beetles can be very long-lived depending on the quality of their food.  In fact, this is the longest lived insect ever recorded.  In Idaho, there is a beetle that has fed on wood for almost forty years!  Insects need the right nutritional requirements in order to turn into adults.  By feeding this beetle dry wood, entomologists in Idaho have been able to keep it in its larval stage for this long period.  So for the Asian Longhorn beetle, its lifecycle can take anywhere from 1-30 years for a full generation.  However, it is believed that most of the population matures in 1-2 years.

The host range of ALB is quite large, attacking just about any hardwood (deciduous) trees.  Maples are generally the preferred host for the beetles.  In fact, the two predominate maples occurring in our area were at the top of its menu.  Chestnuts are also reported to have high infestation rates.

Females chew small circular holes to lay eggs into.  Upon hatching, the young larvae feed on the bark layers of the branch making small tunnels inside the branch.  As the larvae grow, they move into the woody, dead tissue of the tree’s vascular system.  It is here where the majority of the beetle's life is spent mining out the wood.  Once the larvae mature, they pupate.  Adults eclose sporadically throughout the summer.  Most sightings in North America have occurred in early to mid-June.  The adults chew their way out of the tree, leaving up to a ½ inch hole in the branch or trunk and cause a large amount of sap to flow.  High infestations of ALB can be easily seen from afar.  The trees are riddled with bullet holes and a tremendous amount of die back is seen in the canopy.  Usually the trees are first topped along the main trunk then the infestations move into the lateral branches of the canopy.

Background: The beetles originate from temperate, southern China.  ALB is currently a pest in China on planted wind breaks used to slow down encroaching deserts.  This beetle belongs to a species complex of a few different species occurring there.  As of yet, only A. glabripennis has come to North America.  With increased international trade, we can expect to see more exotic pest introductions.  The beetles come in on pallets used in shipment of products from Asia.  This was the case that was reported in Bellingham on July 20, 1998.  The beetle was seen on a cargo pallet and there was evidence of feeding on the pallets.  The first North American infestation was found in Brooklyn N.Y. (1996)and now is now in Chicago (1998).  Coincidentally, I had the opportunity to see the damage first hand in mid-July in Chicago.  We definitely don’t want this critter in our neighborhood.  I saw approximately 50 sugar maples all topped and dying.  Trees under 6 inches in diameter were killed by only a dozen beetles.  It looked as if someone unloaded shotguns into the trees.  In fact, that was what the holes were believed to be, initially, in New York.  The only solution is to eradicate the beetles before they spread.  All trees in infested areas will be removed and burned.  This is an expensive process that will take at least 5 years to complete and a few million dollars.  So far, the tree-less buffer zones made in Brooklyn have been successful at containing the infestation.  Again, we don’t want this one in Bellingham.  As with most ills in our lives, early detection is the only shot, so keep your eyes peeled.