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Pierce's disease is a disease of grapes caused when the bacterium Xylella fastidiosa colonizes the water-conducting system (the xylem) of the host plant and creates a significant blockage. It is spread from plant to plant by sap-feeding insects, such as sharpshooters and spittlebugs.
Under the Hood: The Silent Invasion The Mediterranean Oak Borers Threat Grows by Tim Carl, Napa Valley Features, 2/1/2025 Mediterranean oak borers detected in Lake, Napa, Sonoma counties Morning Ag Clips, 8/6/2020 Attention to oak woodland conservation does not wane amid COVID-19 crisis by UC ANR,...
The Beetle Learn more about the Mediterranean Oak Borer The Disease Learn more about the pathogenic fungi behind the disease Host Trees MOB attacks at least 12 species of oak Distribution MOB has been found in Amador, El Dorado, Lake, Marin, Mendocino, Sacramento, Sonoma and Yolo Counties Counties Impact MOB…
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.
