Quick Summary
The Western Oak Bark Beetle (WOBB) is a small (2mm long) beetle that spreads a fungus (Geosmithia pallida) when it bores into oak trees. Wet discoloration can be observed from the beetle entry holes, including foamy liquid down tree trunks.
Western Oak Bark Beetle, Pseudopityophthorus pubipennis
What to look for:
- wet discoloration on trunk and primary branches
- reddish sap exiting from entry holes after initial attack, followed by foamy, cream-colored liquid
- attack on trees already stressed by drought, disease or other injuries
NOTE: these symptoms can appear similar to ISHB symptoms, but beetle holes are SMALLER
Western Oak Bark Beetle damage
The current distribution map of this pest can be found here.
More Information and Resources:
UCR Eskalen Lab Foamy Bark Canker Disease/Western Oak Bark Beetle
UCR Eskalen Lab Foamy Bark Canker + western Oak Bark Beetle Guide