The Asian Longhorned Beetle (ALB) is originally from China and the Koreas. It is a large 1 to 1 1/2” long beetle that is black with white spots, long black and white striped antennae, and bluish feet.
The first ALB in the United States was found in New York in 1996.
Established populations of the Asian Longhorned Beetle can be found in New York, Massachusetts, and Ohio. A population in Hollywood, South Carolina, in Charleston County was confirmed in June 2020.
Different large longhorned beetles live in South Carolina and often get confused with the Asian Longhorned Beetle. The cottonwood borer is most often confused with the ALB, but it is slightly larger than ALB (about 2” long), is predominately white with black spots, lacks the blueish feet, and has solid black antennae.
Another longhorned beetle confused with ALB is the whitespotted sawyer, which lacks white spots on the antennae and does not have bluish feet.
Several longhorned beetles, known as prionids, can be confused with ALB, but these beetles and brown, not black, and lack the white spots on their body and antennae.
The Asian Longhorned Beetle has a broad range of host species and will feed on 12 different tree genera. Maples, elms, birches, and willows are preferred hosts.
Although not preferred, ALB will feed on planetrees, poplars, horse chestnuts, buckeyes, mimosa, katsura, golden raintree, ash, and mountain ash. Many of these trees are found across South Carolina in both natural and managed landscapes.
Asian Longhorned Beetles adults emerge from host trees in late spring and summer. Adults will emerge from a large round hole in the tree, from which they chewed. Adults will mate and feed on twigs and green bark. Females will chew a concave depression in the bark and deposit a single egg.
Larvae hatch in about 14 days and chew into the tree, feeding on the phloem and xylem, where they feed until they are ready to pupate. Their feeding causes large galleries in the tree, which weakens the tree and makes it susceptible to breaking. Larvae pupate in the wood and adults emerge the following year.
Prevention is the most effective management method. Sadly, once a tree has been infested with ALB, there is little that can be done other than removing the tree. Removed trees should be burned on site or chipped. It is possible to move ALB long distances in pieces of wood like firewood. Contact insecticides will kill adults, but their short time outside the tree makes this management strategy ineffective. Once larvae are inside the tree, insecticides will not work.
Clemson Department of Plant Industries and USDA APHIS are working together on managing the current infestation in South Carolina. If you think you see an Asian Longhorned Beetle, please capture the insect or take a photo and contact the Clemson Department of Plant Industry (invasives@clemson.edu or by calling 864-646-2140). The USDA APHIS webpage has additional ALB resources available at AsianLonghornedBeetle.com.
For more information on Asian Longhorned Beetle, please visit the Home and Garden Information Center website at hgic.clemson.edu. Tune in on Tuesday nights to watch “Making it Grow” at 7 p.m. on SCETV or mig.org. E-mail Outen at callenb@clemson.edu.
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