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Animal and Plant Health Inspection Service
U.S. Department of Agriculture
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Asian Longhorned Beetle - Find It


Exit Hole

Egg Site




Look for Signs of Damage

Besides seeing the beetle itself, there are distinctive signs that can be found on a tree that may mean your tree is infested, and if you see a beetle or suspect that tree damage is caused by the ALB, please report it by calling the hotline at 1-866-702-9938 or filling out the online Report It form:

  • Exit holes – In the warmer months the adult beetles chew their way out of the tree leaving, ¼ inch or larger, perfectly round exit holes.
  • Egg sites – Adult female beetles chew up to 90 oval depressions, called oviposition sites or egg sites, into the bark of the host tree. She lays a single egg beneath the bark at each site. These look like little wounds on the tree, and you can sometimes see the chew marks on the edges.
  • Frass – As the larvae tunnel and feed, it often pushes sawdust-like material or excrement, called frass out onto the ground around the tree or onto the tree branches.
  • Tunneling – After the egg hatches, the larva tunnels into the growing layers (phloem and cambium) of the tree and eventually into the woody tree tissue (xylem). If you have a fallen branch or are cutting wood, you may see this tunneling.


Other Signs of Damage

  • Weeping sap – Tree sap may be seen flowing from the wounds or egg sites.
  • Unseasonable yellowing leaves – Seeing leaves turning colors sooner than they should could indicate the tree is under stress.
  • Branches dropping or dying – If the tree has lost a branch or has a dead branch showing it could be a sign that something is wrong.


Report it!

If you see a beetle or suspect that tree damage is caused by the ALB, please report it by calling 1-866-702-9938 or fill out the online Report It  form.

Before reporting it, please record the area where you found the insect or damage. If possible, capture the insect you think is an ALB, place it in a jar, and freeze it. This will preserve the insect for easy identification. It is also a good idea to take digital pictures of the insect and/or tree damage.

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