Asian Longhorned Beetle

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Asian Longhorned Beetle — A New Invasive Tree Pest In South Carolina

The Asian longhorned beetle (ALB; Anoplophora glabripennis) is not easy to miss – adults of this large, black beetle with white spots, black and white striped antennae, and blueish feet are between 1 and 1 ½” long (Fig. 1). ALB larvae are equally striking as the large, white segmented larvae can be nearly 2” in length (Fig. 2). Established populations in the U.S. are found in Massachusetts, New York, and Ohio, and a new infestation was recently found in Charleston County, South Carolina.

Adult Asian longhorned beetle
Figure 1. Adult Asian longhorned beetle next to a penny. Photo by J. Boggs, Ohio State University, Bugwood.org.
Asian longhorned beetle larva
Figure 2. Asian longhorned beetle larva. Photo by J. Boggs, Ohio State University, Bugwood.org.

ALB uses several different tree species as hosts (Table 1), many of which grow in South Carolina. Host trees can be found in natural or managed landscapes, such as lawns, medians, or public areas.

Table 1. Known host trees for ALB.

AshesFraxinus spp.
BirchesBetula spp.
Buckeyes and horsechestnutsAesculus spp.
ElmsUlmus spp.
Golden rain treeKoelreuteria paniculata
KatsuraCercidiphyllum japonicum
MaplesAcer spp.
Mimosa treeAlbizia julibrissin
Mountain ashSorbus spp.
PoplarsPopulus spp.
SycamorePlatanus spp.
WillowsSalix spp.

Adults emerge in late spring or summer, creating large round exit holes as they chew their way out of the tree (Fig. 3). Adults then mate and feed on the bark of small twigs, though this feeding damage is negligible in comparison to that done by the larvae. Adult females then chew an “oviposition pit” into the bark and deposit an egg (Fig. 4). The egg hatches and the larva chews its way into the tree. As the larva grows, it makes larger and larger tunnels (Fig. 5), and these tunnels eventually kill the tree and make it highly susceptible to breaking. For this reason, larvae are the most damaging life stage of ALB. In many cases, feeding by larvae results in sawdust or shavings being deposited on the tree trunk, branches, or base of the tree (Fig. 6).

ALB exit hole
Figure 3. ALB exit hole chewed by an adult when it left the tree. Photo by J. Boggs, Ohio State University, Bugwood.org.
ALB oviposition pit
Figure 4. ALB oviposition pit at the end of a finger. ALB emergence holes can be seen above and below the pit, and numerous additional oviposition pits can be seen at the bottom of the image. Photo by D. Haugen, USDA Forest Service, Bugwood.org.
Feeding by larval ALB
Figure 5. Feeding by larval ALB can cause large tunnels inside a tree, severely weakening the tree and increasing its susceptibility to breaking. Photo by J. Boggs, Ohio State University, Bugwood.org.
Sawdust/shavings and frass from ALB larvae
Figure 6. Sawdust/shavings and frass from ALB larvae. Photo by PA Dept. Cons. and Nat. Res., Bugwood.org.
Asian longhorned beetle
Figure 7. The cottonwood borer (top) looks similar to the ALB (female in the middle, male on the bottom) but lacks the striped antennae and blue feet and can be characterized as white with black spots rather than black with white spots. Photo by G.J. Lenhard, Louisiana State University, Bugwood.org.
 

The cottonwood borer (Plectrodera scalator) is a native longhorned beetle that looks similar to the ALB (Fig. 7). This beetle is not damaging and can be found in natural habitats across the state.

More information on the ALB can be found on the Asian longhorned beetle Clemson Extension fact sheet. If you think you have found an ALB, please contact the Clemson Department of Plant Industry at invasives@clemson.edu or by calling 864-646-2140.

For more Information on Asian Longhorned Beetle see, HGIC 2021 Asian Longhorned Beetle

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

Author: , Assistant Professor in the Department of Forestry and Environmental Conservation at Clemson University