An exotic beetle has invaded Southern California and targeted coast live oaks. The tiny western oak bark beetle has long been a threat to the oaks but this variety brings a fungus with them that is now wreaking havoc on the iconic oaks. These pests are about the size of a grain of rice. Beetle infestation is identified by the red sap and cream colored foam that pours from holes in the trunks and branches. This is the first symptom of infestation as the sap leaks from the insect entry holes. The beetles lay eggs which grow into larvae beneath the bark and feed on the widespread fungus rather than the tree itself. A single tree can be infested with many beetles at once which greatly increases the chances of death. If just the branches are infected, they can be pruned to stop the spread of the disease. The fungus called foamy bark canker disease blocks water and nutrients from circulating inside the oaks which causes the evergreen tree to turn brown. Once the sap and foam stop flowing, the only evidence of a problem is the small holes. The beetle is infecting trees in Los Angeles, Thousand Oaks, Orange, Santa Barbara, and Monterey counties. The disease is raising wildfire danger concerns as dead trees provide wildfire fuel. In addition to killing the prized trees, the wildlife that depend of the habitat of the oaks is also affected. Species include the Red-shouldered hawks, big, flycatcher’s mule deer, rodents, and quail. Additionally, these oaks are in danger of widespread wife fires due to the drought. Researches from the University of California have been unable to discover the origin of this insidious pest, but they are determined to find and eradicate the source. The insects can be further spread by moving infested firewood.
Orange County Register, Sunday May 11, 2014. Brooke Edwards Staggs, Staff Writer.