The Forest Service said Agrilus coxalis is a wood borer that is so rare it doesn't have an accepted common name, although it will most likely become known as "gold-spotted oak borer." The San Diego Union-Tribune said the wood borer is believed to be at least partly responsible for the death of 10,000 coast live oak and California black oak trees.

The beetle was first found in Southern California in 2004. While it has been found previously in Arizona, Guatemala and Mexico, there is no history of the insect attacking oak trees, the Forest Service said.

The newspaper said scientists suspect the oak borer lacks natural predators in California. Stress from drought may play a secondary role because the trees are unable to defend themselves properly from attack.