Frequently Asked Questions

Where is the current infestation of the goldspotted oak borer located?

The current infestation of the goldspotted oak borer is centered around the Cuyamaca Rancho State Park and the Descanso Ranger District, Cleveland National Forest. The infestation is not isolated to state and federal land, but is also impacting privately owned land.

How can I save my trees from the goldspotted oak borer?

Research is currently underway to assess the efficacy of insecticides. Properly managing infested oak firewood can reduce localized populations and potentially reduce tree mortality. Tarping infested firewood with clear plastic during the warm summer months can potentially reduce beetle populations.

Where did this beetle come from, and how did it get here?

The beetle is native to Guatemala, southern Mexico, and southeastern Arizona. It was first collected in southern California in 2004, but has likely been in the area since the late 1990’s. Researchers believe that the goldspotted oak borer was introduced into southern California on firewood or expanded its range from native regions.

What trees does the goldspotted oak borer attack and kill?

The goldspotted oak borer can attack and kill coast live oak, California black oak, and canyon live oak. This beetle is only currently known to feed on oak tree species. Engelmann oak in southern California is not a known host of this species.

What are the symptoms of injury from the goldspotted oak borer?

Dark black or red staining and D-shaped adult exit holes on the main stem and larger branches and crown thinning and die-back in the canopy all together signify injury from the goldspotted oak borer.

How fast is this beetle spreading?

This group of beetles are very good fliers and can fly up to 10 miles at a time, but commonly stay near its food source (oak trees). However, moving firewood can introduce this beetle into additional areas of California. Please, do not move firewood!