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Oak Borer or Woodpecker on Silver Oak (Quercus hypoleucoides ) #924146

Asked February 02, 2026, 1:43 PM EST

Hello, I have a young (approx. 10 year old) Silver Oak tree that I planted in my back yard. I live near Mt. Tabor Park. I was wondering if it might be susceptible to Mediterranean Oak Borer. I noticed these suspicious holes on the trunk this weekend that look vaguely like woodpecker holes due to their spacing, but would like some advice. I fear the worst! Thanks Pete Walter

Multnomah County Oregon

Expert Response

We've ruled out oak borer - the size of holes appears (although hard to be sure based on the image) to be greater than those made by the borer. 

The Mediterranean oak borer (MOB), Xyleborus monographus, makes small holes about the size of a pencil lead. You would likely see frass, sawdust. MOB can go after all oaks and other hardwoods, but so far in Oregon, they only appear to be a serious concern for Oregon white oaks, Quercus garryana.

More information about MOB: ODA : Mediterranean Oak Borer : Current Projects : State of Oregon and MOB_Pest_Alert.pdf

Sapsuckers create closely-spaced holes, so your picture suggests them as a possibility. Excluding the birds from that section of the tree can be accomplished by wrapping the trunk with burlap (or 1/4" mesh, either plastic or metal). 

Dr. Dana Sanchez Replied February 05, 2026, 2:24 PM EST
Thank you so much for this information. I’ve looked at it a little more closely and did not see any frass. I will wrap some burlap around that area very much. Appreciate the help you guys are great! 

On Thu, Feb 5, 2026 at 11:25 AM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied February 05, 2026, 7:00 PM EST

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