By Jonathan L. Larson, Entomology Extension Specialist, Kentucky Pest News

In the spirit of invasive species awareness, the USDA has declared August as “Tree Check Month.” Specifically, the hope is that people will serve their community by checking for the Asian longhorned beetle (ALB), an invasive longhorn beetle pest that could be devastating to Kentucky forests and landscapes. While this pest is not known to currently live in the Bluegrass State, there are active infestations in Ohio, South Carolina, Massachusetts, and New York as of 2023. August is the peak season for finding adult beetles, and you are asked to contribute 10 minutes of your time by participating in Tree Check Month to help make sure that ALB hasn’t snuck into Kentucky.

Asian Longhorned Beetle Basics

Asian longhorned beetle is a pest that was first accidentally imported to the U.S. in 1996. This initial find was in Brooklyn, NY and was eventually eradicated. Unfortunately, other populations popped up in other parts of New York State, as well as New Jersey, Massachusetts, Illinois, and Ohio in the U.S., and Ontario in Canada.

Adult beetles are 1 to 1.5 inches long with antennae that are longer than the rest of the body. They are black with white splotches on the back, and the antennae are black and white. The legs and feet can have a bluish color. Larvae are cylindrical; they are a type of “roundheaded borer,” and can be up to 2 inches long. Larvae are more cryptic, as they live under the bark of the tree but can be discovered when trees are taken down.

Most of our native longhorn beetles aren’t considered primary pests of trees as they tend to opportunistically feed on dead and dying trees. ALB can infest healthy trees, and over time, the larvae inside will kill the tree. They can be found in 13 different host trees: ash, birch, elm, golden raintree, horse chestnut, Katsura, maple, mimosa, apple, mountain ash, London planetree, poplar, and willow. Larvae will feed down into the heartwood of the tree. When infested trees are cut, the inside often looks like Swiss cheese. Once a tree is infested, there is no way to save it. Areas where this is pest is discovered are quarantined, and infested trees are destroyed. There have already been thousands of trees removed in the United States.

What Should You Do?

To participate in Tree Check Month, go out into your landscape and see if you have any of the hosts listed above. If you do, then inspect your tree for symptoms such as:

• Large exit holes.
• Pits chewed into the bark.
• Sawdust-like material at the base of the tree.
• Dead branches in the upper canopy.

Adult beetles can also be spotted; they are large and in charge, so they can be obvious. They may be on trees themselves or they can be discovered on cars, outdoor furniture, sidewalks, and walls. The latest infestation (in South Carolina) was discovered due to the observations of a citizen in the infested neighborhood. Without their attention, state and national officials would not have known the pest was there. By participating in Tree Check Month, you can help protect the trees of Kentucky and ensure we haven’t been invaded. You can report suspect beetles or symptoms to the UK Department of Entomology through our Facebook page (Kentucky Bugs) or through the Office of the State Entomologist (reportapest@uky.edu).

More Information

If you want to learn more about Tree Check Month or the Asian longhorned beetle, you can find info at the following USDA sites:

• USDA Asks Public to Help Check Trees for Asian Longhorned Beetle (link)
• Asian Longhorned Beetle (link)