Tree Care

5 Signs Your Tree has ALB

By Sheereen Othman | August 1, 2016

Today marks the first day of Tree Check Month—the annual campaign to check for signs of Asian Longhorned Beetle (ALB). ALB is an invasive insect that feeds on certain hardwood trees, eventually killing them. ALB is most active during the summer and fall, which makes the signs of ALB infestation easier to spot. It’s important to routinely check trees for disease and pests to prevent the spread of them to other trees.

If you spot any of the following signs on your trees, they may be affected by ALB. Once a tree is infested, it must be removed to prevent it from infecting other trees. Thousands of trees have already been lost to ALB, making it important to stay proactive in identifying the signs.

Signs of ALB

  1. Exit holes: Adult beetles chew their way out of the tree, leaving one-quarter inch exit holes.
  2. Egg Sites: Female beetles chew up to 90 oval depressions, called oviposition sites, or egg sites, into the bark of the host tree, and then lay a single egg beneath the bark resembling a wound on the tree.
  3. Frass: As the larvae feed they leave a sawdust-like excrement on the ground or branches.
  4. Tunneling: Larva tunnel through the layers of the tree.
  5. Dead branches: If the tree has lost a branch or has a dead branch showing, it could be a sign that something is wrong.

There are certain trees that are prone to the pest. If you have any of the following trees it’s especially important to routinely check them.

Trees at Risk

•  Ash

• Birch


Goldenrain tree


• Katsura

London planetree


• Mimosa


• Poplar

• Willow

If you think you’ve spotted signs of damage from ALB contact your state ALB eradication program office or plant health director’s office.

Missed our first post about ALB? Catch up on it here.

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  • Reply Devon Olson August 4, 2016 at 12:49 am

    This is definitely something to watch out for now that I’ve read your info. During my time landscaping I don’t think I’ve come across any ALB infestations, however, in Vancouver I know that we have had a huge problem with pine beetles killing off hundreds of trees in dense forest areas. I like how you give the signs of what to look for because some may just assume that a beetle wouldn’t cause this severe harm to the trees.

  • Reply Barbara Elliott August 10, 2016 at 3:41 pm

    I was so disappointed to fill out the tree survey only to find that if I do not donate I cannot even submit let alone be eligible for the prizes! Is this even legal ? To bad Arbor Day has to stoop to such trickery!

  • Reply The Member Services Team August 11, 2016 at 9:41 am

    Hi Barbara,

    Thank you for your comments concerning our survey. Your feedback is important to us and has been forwarded to the appropriate department here at the Arbor Day Foundation.

    The free gifts, as well as the ten tree seedlings are sent as a “Thank You” for becoming a member of the Arbor Day Foundation. With a membership contribution, we will send a subscription to our bimonthly Arbor Day newsletter, and a copy of the Tree Book with important tree care information and discounts on nursery stock.

    The annual Tree Survey has been popular and helpful for us to identify people’s sentiments about trees and benefits of trees. To receive the best response, we work with many respected environmental nonprofits, charities, publishers, and gardening companies to try to identify people who might be interested and inclined to participate in the Tree Survey.

    Barbara, if you have any further questions or comments, please feel free to contact our Member Services team at 1- 888-448-7337, Monday through Friday, 8:00 a.m. to 7:00 p.m., Central Time.

  • Reply JJ- August 23, 2016 at 4:04 am

    I tried the links for the ALB eradication for the websites and they come up with error 404 website not found. Perhaps a server issue with owner. Can you please recheck the links?

  • Reply Tree Pros August 25, 2016 at 8:41 pm

    Wow, this is the first I’ve ever heard of ALB. I guess I’ll have to start watching out for this. That really sucks that tree must be removed if infested.

  • Reply Tree removal September 12, 2016 at 7:09 pm

    I own a tree company and thought I know a thing or 2 about trees and bugs and trees with diseases. But this is the first I’ve ever heard of ALB. I guess I’ll have to start watching out for this. Is there no other way other than removing the entire tree if we spot ALB? WOuld sure hate to remove a whole tree!

    • Reply Sheereen Othman September 19, 2016 at 8:57 am

      Unfortunately, the only way to prevent ALB from spreading is by removing the tree altogether. Leaving an infected tree can lead to wider infestation.

  • Reply Bob October 25, 2016 at 2:00 pm

    Wow, I hadn’t heard of ALB before this article either. Great information to know. In my years as an Arborist, I haven’t come across it yet, but I’m glad I stumbled across this article just in case I do in the future.

  • Reply Emily August 12, 2017 at 9:42 pm

    Another pest that attacks the trees are the so-called “drill larvae” they eat the wood from the trunks and branches until they kill the tree. They´re very common in young trees, mostly fruit trees. The main treatment is to remove heavily affected trees to prevent them from infecting others; it is also recommended to introduce into the holes produced by the larvae, cotton wires filled with insecticides to clean the nests.

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