Kenneth R. Law, USDA APHIS PPQ, Bugwood.org
Exit holes in canopy:
Pennsylvania Department of Conservation and Natural Resources, Bugwood.org
ALB egg sites, Dennis Haugen, USDA Forest Service, Bugwood.org
Asian Longhorned Beetle (ALB) is a large black beetle native to China, with unique white spots on its abdomen and antennae. Sometimes its legs have a bluish color. It seems to prefer maple trees, but has been found to damage many more tree species, including Ash, Birch, Sycamore, Willow, Elm and others. ALB are pretty big for an insect, an adult can grow to be up 1-1.5 inch long, with antennae up to three inches in length! In spite of its size, the majority of its life cycle happens inside of trees, making it hard to detect. Eggs are laid on the bark of trees; after hatching, larvae burrow into the tree and create
“galleries” by eating tissues under the bark. Then it bores deeper into the tree to pupate. Finally the adult chews its way out of the tree, leaving a characteristic
dime sized round exit hole. Egg laying sites are also distinctive and can be numerous, seen as small rough impressions in the bark. All of this can happen high up in the crown of the tree, making it difficult to find new infestations until trees begin to die.
ALB infestations have been found in New York, New Jersey, Massachusetts, Illinois, Ohio and most recently in South Carolina. Some infestations have been eradicated, meaning the beetle has been removed completely from the area. In New York, Ohio, and Massachusetts ALB is being managed cooperatively by state and federal agencies. As part of this process some host trees are removed completely while others can be treated with pesticides. ALB usually is spread when people accidentally take them somewhere new, especially in firewood. Limiting movement of untreated wood is very important to prevent pests such as ALB.
Monitoring and Reporting:
This insect is not yet in Prince William County, however, early detection can help to prevent ALB from establishing in our area. Our branch performs trap surveillance and also visual monitoring for ALB in late summer and fall.
Residents are encouraged to keep an eye out for this beetle:
-Adult Beetles are particularly active around August- this is a good time to check your trees for the beetle, evidence of tree die back, frass and sawdust at the base, exit holes and egg deposit sites.
-If you suspect that you have seen the beetle, take a photo or capture and freeze it if possible. Sightings can be reported to the Virginia Department of Agriculture and Consumer Services at 804-786-3515, the United States Department of Agriculture at 866-702-9938 or online here.
The PWC Mosquito and Forest Pest Management Branch is also available to investigate.