An oak's Public Enemy #1, the goldspotted oak borer. Photo provided by UC.

Scientists at the University of California are asking for the public’s help in combating a tiny beetle that’s threatening our native oaks.

The goldspotted oak borer has already killed 20,000 coast live oaks, black oaks and canyon live oaks in the San Diego area. The fear is that the beetles could spread throughout the state aboard loads of cheap firewood generated from the many dead and dying trees.

The beetle is native to southern Arizona, Mexico and Guatemala. Scientists suspect it hitch-hiked its way into California on firewood, since until now, the Mojave Desert had served as an inhospitable barrier.

The voracious appetite of the beetle’s larvae is the problem. The larvae feed on the cambium, which is the layer beneath the bark. According to UC, “Larval feeding destroys the cambium’s vascular system, which carries water and nutrients through the tree. The tree starves and dies.”

That’s obviously not a pretty sight. And beyond the threat to our beautiful oaks, the beetles endanger our oak woodlands and all the other species that thrive there.

UC entomologists are now searching for the best natural predators to attack the strain of beetles that’s killing the southern California oaks.

In the meantime, they offer the following tips to keep the goldspotted oak borer from spreading to other parts of the state:

• Do not transport oak firewood into or out of campgrounds or parks.

• Chip infested oak wood to 1-inch pieces

• Cover stored oak firewood with 6 mm, UV-stabilized, durable plastic tarps in the spring. Secure all the edges of the tarp to the ground to prevent beetles from escaping.

• Season oak firewood. Remove the bark and place the wood in direct sunlight.

For more information about the beetle, visit the UC Riverside Center for Invasive Species website at

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