"Why didn't Noah swat those two mosquitoes?" ―Unknown
And for that matter, why didn't he swat the Goldspotted oak borer?
Agrilus auroguttatus is an invasive pest contributing to the ongoing oak tree mortality occurring on federal, state, private, and local Native American lands in Riverside and San Diego County. If you have California Black Oak or Coast Live Oak, you need to watch for signs of this pest. Evidence of an infestation may include a weakening of the top of the tree or small “D” shape holes in the bark. As the weather warms, the insects exit the trees. They lay larvae that feed beneath the bark of oaks and damage the movement of nutrients in the tree. They do not kill the tree quickly, but they will weaken the tree and eventually kill it.
There are currently no effective tools for protecting trees once infestation occurs.
The only good news is that entomologists believe that trees larger than 20 inches in diameter seem more susceptible to them. Officials are still testing to determine if any insecticides are effective against this pest. If I find it in any of my oaks, I'm going to seriously consider burning them and isolating any other oaks that do not yet show signs of infestation.