Insects and Spiders - invasive

Mediterranean Oak Borer (Xyleborus monographus) on Aug 14, 2024

Submitter does not have a specimen
EDRR Status: Population assessed

Description of specimen

I observed multiple perfectly round approximately 1/16th of an inch entry wounds on the main trunk of the tree. There are several entire mature branches dying back in the crown above.

Commentary

No definitive signs of MOB. The exit holes were far too large (see new image with sharpie for scale), MOB holes are the width of the tip of a ballpoint pen. I did see extensive thinning and branched back potentially due to drought or disease (no evidence of fungal rot indicated externally). Spoke to the landowner about providing supplemental water as a test to see if it rebounds.

Christine Buhl
Aug. 21, 2024, 5:03 a.m.

Location

There is a 22.5" DBH Oregon White Oak in the front yard at 731 NE 157th Avenue Portland, Oregon

Expert Reviewer

Christine Buhl
Oregon Dept. of Forestry

© 2025 Portland State University | Contact us for questions regarding site content