A new and potentially serious threat to some of North America’s most beautiful and popular trees is the Asian Long-horned 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 Long-horned Beetle infestations have been discovered in Brooklyn and Amityville, New York, and in Chicago, Illinois. In all instances where Asian Long-horned Beetles have been found, authorities have reacted quickly to stop the infestation from spreading.
Trees favored by the Asian Long-horned Beetle are predominantly maples, but infestations have also been discovered in horse chestnuts, poplars, willows, elms, mulberries, black locusts, and many other varieties.
Asian Long-horned Beetles are very large insects, with bodies ranging from 1 to 1 ½ inches (2.5-4 cm) in length and with antennae which can be as long as four inches (10 cm). They are shiny and black with white spots and have long antennae that are banded black and white. These beetles have wings and can fly, although only for short distances because of their size and weight. The Asian Long-horned Beetle, like all types of boring insects, are extremely destructive because, as the beetle larvae burrow deep within a tree to feed, they disrupt the tree’s vascular system. Continued feeding causes structural defects in the tree 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. Active Asian Long-horned Beetle infestations, if left untreated, can quickly kill otherwise healthy adult trees.
Mature beetles emerge from trees beginning in late May and lasting through October, 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’ evident on the ground or lower branches.
If you suspect the presence of Asian Longhorned Beetles, contact local USDA officials immediately so that they can take steps to contain the outbreak.