Mediterranean oak borer (MOB), Xyleborus monographus, is a novel and major concern for Washington’s urban forests and oak tree population. Learn how you and your community can become more prepared and stay in the loop about MOB by registering to attend the online workshop hosted by Washington State University.

The workshop will focus on the biology, impacts, monitoring, and management of invasive ambrosia beetles,with an emphasis on the Mediterranean oak borer. It will include 7-8 presentations and a discussion to identify needs and coordinate responses in Washington.

Mediterranean Oak Borer (MOB) is an invasive ambrosia beetle that primarily infests living oak trees. Washington is home to not only the native white oak, the Garry oak, but several other species that may be susceptible to MOB. While MOB has not been found in Washington state yet, it has been located in our neighboring state of Oregon.

MOB was first captured in the PNW in a trap near Troutdale, OR in 2018. Then in 2022, it was confirmed in two Oregon white oaks (Quercus garryana) near Troutdale and Wilsonville. And then in 2023, approximately 30 trees were confirmed positive for MOB in Wilsonville.

This beetle bores into the tree, just below the bark, and carries with it a fungus that then spreads through the tree’s conductive tissue, causing that vascular system to clog and susceptible trees to wilt.

Insects like MOB are often spread through humans transporting infested firewood or other wood products. Arboriculture and Urban Forestry professionals should arm ourselves with the knowledge needed to identify, prevent, and manage this forest pest before it becomes a statewide issue for our only native oak species. We need to be monitoring for this pest and preparing for its arrival due to the close proximity to our bordering Washington cities that have Oregon white oak populations. Don’t forget to register for the online workshop today!