Asian Longhorned Beetle (Anoplophora glabripennis)

Tagged as: Asian longhorned beetle, Anoplophora glabripennis

The Asian longhorned beetle is an insect that can do very serious damage and even kill trees while it is in its larval stage. It was first discovered in the Ravenswood area of Chicago in 1998, as well as in two Chicago suburbs, Addison and Summit. A previous infestation was discovered in New York in 1996. It is believed that the beetle, while in the larval or pupal stage, was transported here in the wood of shipping crates from Asia.

HOSTS

In the Chicago area, the host tree has overwhelmingly been maple (Acer spp.), specifically Norway, sugar, and boxelder. However, horse chestnut, black locust, elm, rose of Sharon, and green ash have also been attacked. The insect is native to China, Korea, and Japan, where it attacks maple (primarily silver maple and boxelder), poplar, willow, mulberry, plum, pear, black locust, and elm. In New York, in addition to maples and horse chestnuts, poplars and willows have been attacked.

LIFE CYCLE

Adult beetles emerge from the trees from May to October by chewing their way out of the trunks. Peak emergence time is thought to be July. The exit holes are between 3/8" and 11/4" inches in diameter, round and very deep. Most of the exit holes found in Chicago are in the larger branches of the trees. Sometimes heavy sap is seen oozing out of the emergence hole or egg niches, and occasionally an accumulation of coarse sawdust and frass is seen at the base of an infested tree.

The adult Asian longhorned beetle is about 11/4" in length, and glossy jet black with small white spots on its wing coverings. It has long antennae that are distinctly banded black and white. The antennae of the males are 21/2 times their body length, while the female antennae are 13/4 times their body length. Because they are heavy-bodied insects, they cannot fly great distances.

After mating, female beetles chew depressions in trees to lay eggs. These depressions can be oval to round in shape. In Chicago, oviposition scars (where eggs are deposited) were frequently found lower in the trunk, as low as a few inches above the soil line. When the eggs hatch, the larvae begin feeding under the bark. The first three instars (larval stages) feed in the tree’s phloem (food-conducting vessels), then late third and early fourth instars feed on xylem (water-conducting vessels). Mature larvae burrow winding galleries in the heartwood. This is what eventually kills the tree during a heavy infestation.

CONTROL

Presently, there is no known control in this country, besides destroying infested trees. Because most of the Asian longhorned beetle’s life cycle is spent deep inside the tree, they are difficult to control. The beetles do have a few natural enemies in their native Asia, including nematodes, woodpeckers, and parasites, but their natural enemies are unable to keep them from being a serious problem even there.

Early detection of infestations and quick response treatment is important to limit the spread of this insect because it may become a significant tree pest in this country. If you believe you have seen the Asian longhorned beetle, please collect an adult beetle in a jar, place the jar in the freezer, and notify the U.S. Department of Agriculture in your state. In Illinois, call the Illinois Department of Agriculture hotline number at

1-800-641-3934

The following is a list of trees not known to be susceptible at this time to attack by the Asian longhorned beetle:

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