Male Asian longhorned beetle US Forest Service

Introduction

A new and potentially serious threat to some of North America’s most beautiful and popular trees is the Asian Longhorned Beetle (Anoplophora glabripennis).  Native to parts of Asia, the beetle is believed to have arrived in North America in the wooden packing material used in cargo shipments from China.  Isolated Asian Longhorned Beetle infestations have been discovered in Brooklyn and Amityville, New York, and in Chicago, Illinois.  In all instances where Asian Longhorned Beetles have been found, authorities have reacted quickly to stop the infestation from spreading. 

Sawdust from beetles chewing their way out of a tree US Forest Service

Trees favored by the Asian Longhorned Beetle are predominantly maples, but infestations have also been discovered in horsechestnuts, poplars, willows, elms, mulberries and black locusts.  Currently, there is no known chemical or biological defense against the Asian Longhorned Beetle and, in North America, they have few natural predators. In all cases of infestation, the affected trees are cut down and the wood destroyed.

What do they look like?

Mature Asian longhorned beetles are very large insects with bodies ranging from 1 to 1 ½ inches (2.5-4 cm) in length and antennae which can be as long as four inches (10 cm).  They are shiny and black with white spots and long antennae banded black and white.  These beetles have wings and can fly, although only for short distances because of their size and weight.

What does it do?

The Asian longhorned beetle is extremely destructive.  The damage is caused by beetle larvae which burrow deep within a tree to feed on its food and water conducting vessels.  Continued feeding causes structural defects and eventually kills the life-sustaining cambial layer by girdling.  Mature beetles then burrow out of the tree leaving holes the diameter of ball-point pens.  Heavy Asian Longhorned Beetle infestations can kill otherwise healthy adult trees.

When is it active ?

Mature beetles emerge from trees beginning in late May and lasting through October with a frequency peaking in July.  Tree infestations can be detected by looking for tell-tail exit holes 3/8 to ¾ inches in diameter (1.5-2 cm) often in the larger branches of the crowns of infested trees.  Sometimes sap can be seen oozing from the exit holes with coarse sawdust or ‘frass’ in evidence on the ground or lower branches.

What can a homeowner do to control the Asian longhorned beetle?

If you detect the presence of Asian Longhorned Beetles, contact local forestry officials immediately so that they can takes steps to contain the outbreak.  Unfortunately, the only way currently known to combat the Asian Longhorned Beetle is to destroy the infested trees.  But, while cutting down mature trees is a tragedy, it is preferable to permitting this new menace to spread.

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