Asian Longhorned Beetle
Emerging Threat Note: This insect is not established in Tennessee, but we actively monitor for it and encourage residents to report potential sightings.
The Asian longhorned beetle (ALB; Anoplophora glabripennis) is a federally quarantined wood-boring beetle that causes significant damage to trees in North America. While not found in Tennessee, this beetle has been detected and quarantined in multiple states since it was first detected in 1996 in New York. Preventative measures, such as not moving untreated firewood, along with early detection and eradication are the most effective ways to protect our Tennessee forests from this pest.
This beetle is native to China and Korea, and was found in the U.S. in 1996, and likely introduced to the U.S. multiple times in wood packaging material from its native range. Currently, populations exist in only 4 states, all of which have active quarantine areas where eradication efforts are in effect. Beetles are often inadvertently moved to new places in cut firewood or wood packaging material.
This insect causes damage to trees by tunneling throughout the sapwood and heartwood of trees or branches. Larval tunneling greatly reduces the tree’s strength, making infested trees potentially hazardous. This tunneling within the sapwood can also damage a tree’s ability to move water and nutrients through its trunk or branches, eventually killing these trees within 7 to 9 years. There is no known treatment once a tree is infested, so removal of infested trees is always necessary, both to reduce hazards and prevent the spread of this damaging pest into new areas.
Asian longhorned beetles are large (1-1½” long) with shiny black wings and bodies with white spots and long black and white-banded antennae; antennae can be 1.5 to 2 times the body length of the beetle. Adults chew perfectly round holes (~ ½” diameter) when they exit the tree; a general rule of thumb is that a standard No. 2 pencil can typically be inserted at least an inch into exit holes of ALB. Trees infested with Asian longhorned beetle may show unseasonable yellowing or dropping leaves, sap seeping from the bark, or dead or dying branches.
Females will chew shallow depressions in the bark where eggs will be laid, which may be visible along with the round exit holes in trees within infested areas. These eggs are laid in many hardwood species, especially maples. As larvae develop, they tunnel through the cambium and heartwood of branches or the trunks of trees. This tunneling can be visible in trees or branches if they break or are cut, and sawdust and frass may be visible around the base of trees or branches where infestations of ALB are present.
Because other native beetles may cause some similar symptoms in trees, it is helpful to find the beetle itself to properly identify it. However, reporting any suspected ALB is important to detecting a possible infestation early and proactively managing it.
Currently, infestations exist only in Massachusetts, New York, Ohio, and South Carolina, although infestations have been detected and eradicated in Illinois, New Jersey, parts of New York, and Ontario, Canada. The most recent infestation, near Charleston, South Carolina, was detected in 2020. All known infestations are under federal quarantine and eradication efforts are underway to eliminate ALB from these areas and prevent its spread.
Early detection is vital to managing this pest. Current infestations in the U.S. have primarily been detected and reported initially by homeowners, emphasizing the importance of reporting suspected pests to state or federal agencies.
Once infestations are detected, the United States Department of Agriculture, Animal and Plant Health Inspection Service can issue a quarantine and begin efforts to eradicate the pest. Eradication of the pest involves removal of trees and destruction of infested material.
What Can You Do?
To prevent the spread of ALB to new areas, the easiest step that can be taken is to not move untreated firewood. If traveling to areas with ALB infestation, follow all regulations for movement of wood materials. Movement of firewood or untreated wood packaging has been linked to the movement of ALB and a variety of other forest pests.
If you find suspect beetles or damage, please report sightings to the Forest Health Program Specialist at the Report a Pest link: