UC ANR is committed to providing an accessible and inclusive web experience for all users. If you encounter an accessibility barrier or need content in an alternative or remediated accessible format, please contact anraccessibility@ucanr.edu.
Signs & Symptoms Identifying the presence of MOB infestations Look-alikes Other pests with similar symptoms Waste Disposal How to handle infested wood and green waste Reporting How to report an infested tree...
Pest Alert in Spanish, August 2021 Pest Alert, July 2020 Establishment of a non-native xyleborine ambrosia beetle, Xyleborous monographus (Fabricius) Coleoptera: Curculionidae Scolytinae), new to North America in California, June 2020 Reducing the Spread of Invasive Pests in Cut Wood, UC IPM Green B...
The Mediterranean oak borer (MOB) is an ambrosia beetle native to the Mediterranean region, including Europe, the Middle East, and North Africa, where it primarily attacks oak species.
All ambrosia beetles (like MOB) grow fungi inside their galleries and use it as food for larvae and adults. Some of these fungi can be pathogenic and cause tree diseases that may lead to tree decline and, sometimes, tree death.
MOB attacks at least 12 species of oaks. In California, it has been found infesting two species of white oak: most commonly valley oak and, to a lesser extent, blue oak. A single, very limited attack was found in a severely distressed California black oak. Valley Oak Valley Oak in Calistoga.
MOB creates tunnels (or galleries) in the trunks and branches of host trees. It initially attacks the crown of the tree, where it will kill individual limbs. Infestation can continue over several growing seasons, eventually invading the main trunk and killing the entire tree.
Oak trees infested with MOB are most easily identified by damage caused by the beetles tunneling activity (galleries) in the xylem. MOB galleries are often: Trellis-like Very crowded and intersecting Fanning out in a single plane 1.2-1.
In Northern California, two native ambrosia beetles in the genus Monarthrum also create black-colored galleries in oaks. Monarthrum galleries branch from a single point like a palm leaf and do not cross over neighboring galleries.
Take the following steps to limit the spread of MOB: Moving infested wood artificially spreads pests to other areas. Buy It Where You Burn IT, Dont Move Firewood. firewood.ca.gov Cut stumps as low to the ground as practical and cover with soil if possible.
Under a collaborative program, agencies and organizations are working together to determine the distribution, impact and possible prevention methods of tree mortality caused by Mediterranean Oak Borers/Pathogen Complex Disease (MOB/PC).
