UCCE Master Gardeners of Orange County
University of California
UCCE Master Gardeners of Orange County

Shot hole borers

Shot hole borers text

Invasive shot hole borers, both polyphagous shot hole borers and Kuroshio shot hole borers are killing trees throughout Orange County.  Both beetles introduce Fusarium fungus into the tree, which eventually kills the tree.  Over forty species of trees can be affected.

Polyphagous shot hole borers make tiny holes in the bark of trees they invade, about the size of the tip of a ballpoint pen.  On some species of trees, the hole may be ringed with a sugary exudate (avocados) or a dark stain.  Other symptoms can include branch dieback and the presence of sawdust-like frass.

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Depending on how extensive the infestation is, you have several management options.

Click here for an online assessment tool.

If you can’t find the answer on the site, don’t despair! We also have the capacity to personally assist you through our hotline.  Just contact us by email or by phone (voicemail) at 949 809-9760 and we will respond to your inquiry.
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