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The
Asian longhorned beetle is a large wood-boring beetle native to
China and
other Asian countries. Its scientific name is Anoplophora glabripennis
and it is in the Order, Coleoptera along with
the other beetles. Populations of this beetle were recently discovered in New York and Chicago.
Larvae of the Asian longhorned beetle feed in many kinds of trees, including important
ornamental and forest species. This bulletin is designed to provide you with information
about the beetle and how to recognize it.
 The Asian longhorned beetle is an exotic insect - it is not
native to North
America. It was discovered infesting trees in two cities on Long Island,
New York, in 1996. Another population was found in a suburban neighborhood in Chicago in
1998. Larvae of the Asian longhorned beetle feed in the wood of tree branches, stems and
large roots. The large tunnels (galleries) created by larvae can cause branches or stems
to break and can eventually lead to tree death. Because the insect is not native to North
America, it has no known natural enemies here, and our trees have low resistance to this
pest. Currently, trees that are known to be infested with Asian longhorned beetles must be
cut down and destroyed, a process that is often distressing for residents in affected
areas. Many scientists and regulatory agencies are working together to locate any existing
populations of this beetle and to try to prevent new populations from becoming
established.
The Asian longhorned beetle is native
to China, Korea and Japan. Therefore, entomologists expect this beetle to be able to tolerate a wide range of weather conditions in North America. It could probably
survive at latitudes ranging from that of Cancun, Mexico, to Milwaukee, Wisconsin. Most experts believe that the Asian longhorned
beetle was accidentally introduced into North America from
China in wood crating, pallets or wooden
"dunnage" - the wooden logs and braces used to support cargo during
shipping. Once trees were infested, however, tree trimmers may have moved sections of
infested wood from one city to another, resulting in at least one additional infestation
in New York.
This is a large, handsome beetle
sometimes called the "star sky beetle" in Chinese
literature. The adults are shiny black with white spots on
the upper and lower body, and about I inch long and Y4
inch wide. The antennae are very long, with alternating black and white bands.
Larvae are plump, white to pate yellow grubs. The legless body is round. Larvae will be
found in the wood of tree branches, stems or large roots. Young larvae are small, but
older larvae can be l to 2 inches long.
Adult beetles are usually active from May to October, with peak activity
occurring in midsummer. After mating, a female adult chews a
round or oval pit through the outer bark and into the
cambium area between the bark and the wood. She then deposits an
egg under the bark at the bottom of the pit. Adult beetles live for several weeks, and
each female can lay from 25 to 40 eggs during her lifetime. The eggs hatch within I to 2
weeks, and the young larvae feed in the cambium area, just under the bark.
 Older
larvae tunnel deeper and feed in the wood. Larvae periodically push coarse sawdust and
fecal particles out of their galleries. The larvae spend the winter in the wood. They
pupate in late spring or early summer, and the new adults emerge from the tree in early to
midsummer. The large adults each leave a round hole in the tree where they emerge. The
young adults will feed on the bark of twigs and small branches before mating. The Asian longhorned beetle generally has one generation per year, although some beetles require two
years to complete their development.
 Hosts of the Asian
longhorned beetle include many species that are important ornamental
or forest trees in North America. In Asian countries, the beetle will infest
maples, box
elder, poplars, willow,
mulberry, plum, pear, black locust and elm trees. In the New York
infestation, several species of maple were infested, including Norway, sugar and silver
maple, and sycamore. Horsechestnut, poplar, box elder and willow trees were also infested.
Asian longhorned beetles will attack live, apparently healthy trees, young and
old trees, stressed trees, and recently cut trees, logs or stumps. To date, the two known
infestations of Asian longhorned beetles in North America have occurred in urban areas.
Chinese scientists have reported that trees growing in windbreaks and plantations are
attacked by Asian longhorned beetles more often than trees in forest stands.
Tree damage is caused mainly by the larvae
feeding in tunnels in the sapwood and heartwood of the tree.
An individual tunnel, called a gallery, may be 4 to 6 inches
long and 1/2 inch wide. High numbers of galleries or
repeated attacks will eventually kill individual branches or even
whole trees. Branches and trees with high numbers of galleries are also likely to break in
strong winds. Feeding by adult beetles on twigs and small branches can cause some small
twigs to die. These small wounds and the pits chewed out by egg-laying females could also
lead to infection by tree diseases.
When an adult Asian longhorned beetle
completes its development and emerges from a tree, it leaves a round hole about
1/2 inch in
diameter. These round holes can be found anywhere on the tree, including branches, the
trunk or large exposed roots. Piles of coarse, sawdust-like frass may be found in the
crotch where a branch meets the main stem or at the base of an infested tree. Sap
may run from the wound, darkening the bark of the tree. You may also be able to find the
small round or oval pits in the bark where adult females laid eggs. When an infested
branch or stem is cut and split open, the tunnels created by the feeding larvae will be
present in the wood. Asian longhorned beetles often seem repeatedly to infest the same
portion of the tree year after year until that area dies or breaks off.
There are many species of
longhorned beetles in
North America. These native beetles also feed in tunnels in the sapwood of many kinds of
hardwood and conifer trees. Pine sawyer, for example, is a common beetle found in most
pine forests. Other native species include the
sugar maple borer, the locust
borer and the poplar borer. Entomologists can help you distinguish between native
wood-boring beetles and the Asian longhorned beetle.
Currently, federal agencies are attempting
to eradicate the two known populations of Asian longhorned beetles in the
United States. Trees throughout the
areas known to be infested are carefully examined for signs of Asian longhorned beetle
presence. All trees infested with Asian longhorned beetles must be cut down and chipped to
ensure that no life stages survive. Scientists hope soon to begin working with Chinese
colleagues to find new management options for ornamental trees infested with Asian long-
homed beetle. At the present time, there are no known strategies for managing this insect
with insecticide treatments. Also, there are no predators, parasitoids or diseases known
to affect Asian longhorned beetles in North America.
Federal and state regulatory agencies
regularly inspect ships, crates and dunnage at shipping ports and warehouses throughout the state. These
inspections are designed to detect new populations of exotic pests before they can become
established. Traps and trap logs are often used to help regulatory personnel find
wood-boring beetles, bark
beetles and other pests likely to infest crating material and dunnage. Inspectors are trained to carefully examine crates and other wooden material that
is shipped from Asian countries to ensure that this material is not infested by the Asian
longhorned beetle. Information on the Asian longhorned beetle, including color photos, has
been provided to warehouse operators and importers to enlist their assistance in detecting
new Asian longhorned beetle populations. In addition, new regulations recently took effect
that require crates and dunnage shipped from China to be free of bark and kiln-dried or
fumigated to reduce the risk of future introductions of wood-boring pests.
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