August is Tree Check Month!

The USDA has declared August as “Tree Check Month” to foster awareness of the Asian longhorned beetle (ALB), an invasive pest that could be devastating to Kentucky forests and landscapes. Currently, the pest is not known to live in the Bluegrass State. There are active infestations in Ohio, South Carolina, Massachusetts, and New York as of 2022. August is the peak season for finding adult beetles and you can contribute 10 minutes of your time to help make sure that ALB hasn’t snuck into Kentucky by participating in Tree Check Month.

Asian Longhorned Beetle Basics

Asian longhorned beetle is a pest that was accidentally imported to the U.S. first 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 hard to find as they live under the bark of the tree but can be discovered when trees are taken down.

Figure 1: Adult Asian longhorned beetles are distinctive black longhorn beetles. They have white splotches on their back and antennae that are longer than the rest of their body. (Photo: M. O’Donnell and A. Cline, Wood Boring Beetle Families, USDA APHIS PPQ,

Most of Kentucky’s 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.

ALB can be found in 12 primary hosts: 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 sized exit holes.
  • Pits chewed into the bark.
  • Sawdust-like material at the base of the tree.
  • Dead branches in the upper canopy.
Figure 2: Asian longhorned beetle creates distinctive symptoms such as large exit holes that adults emerge from (top image) and egg laying pits that females chew into the bark (bottom image). (Photos: Joe Boggs, Ohio State University,

The adult beetle can also be found. 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 their Facebook page (Kentucky Bugs), through the Office of the State Entomologist, or through your local Extension office (locate KY Extension offices here).

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

  • Free Downloads for Tree Check Month (link)
  • Asian Longhorned Beetle (link)

By Jonathan L. Larson, Entomology Extension Specialist

Posted in Landscape Trees & Shrubs
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