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What's burrowing in my Goat Willow?

Over the past few months, I’ve noticed little piles of woodchips appearing around the base of my Goat Willow. There are a few holes around the base of the trunk, and I’m concerned something is burrowing around inside it, chewing through the trunk and expelling these woodchips.

The tree is approximately 5 meters tall, and less than 17 years old. The main trunk is approximately 30 cm in diameter but quickly splits into 2 separate trunks.

Please find a full selection of photos here:

Any ideas what this could be? Is it putting the tree at risk? If so, what can I do to save the tree?




  • OnopordumOnopordum Posts: 390

    That's very interesting. Where in the country are you?

    I can only think it's some kind of insect larva but I don't know what. Hornet Clearwing Moth maybe?

    I suspect that the trunk might already have been rotten inside the base, probably a consequence of the fork. I'm not sure there's a great deal you can do about it.

  • jcwackyjcwacky Posts: 5

    I'm up in Edinburgh.

    Thanks. I had wondered if it could be the hornet clearing moth, as it seemed to match the symptoms. Wasn't sure how common it was in Scotland though. And I couldn't find any info about if they were a threat to the tree. 

  • OnopordumOnopordum Posts: 390

    Looking at these again I'm thinking they might be Great Spotted Woodpecker holes in search of larvae of the Lunar Hornet Clearwing, not Hornet Clearwing. Seems Lunar is the one that feeds on Goat Willow, and it does occur in Scotland. Do you have woodpeckers coming to the feeders?

  • jcwackyjcwacky Posts: 5

    Thanks, although I've never seen a woodpecker here.

    So if it is the lunar hornet moth, where is the best place to go to find out if they are a threat to the tree and what I can do about it?

  • OnopordumOnopordum Posts: 390

    Since they burrow inside the trunk I don't think there's much you can really do - I'd just keep on observing and see how it develops. Willows are pretty tough and good as resprouting after damage if necessary.

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