Goldspotted oak borer. First identified in eastern San Diego County in 2004, the goldspotted oak borer, Agrilus auroguttatus, has killed over 25,000 California native red oaks since its arrival and has now been detected in Riverside County. Larvae feed deep within the phloem, and adults are rarely seen. Infestations are recognized by the presence of D-shaped exit holes on trees, often accompanied by bark staining and crown decline. There are currently no good ways to manage the pest in moderate to severely infested trees. Contact your agricultural commissioner if you find infestations outside the known infested area.
Photo Bark staining on coast live oak caused by larvae of the goldspotted oak borer. [Photo by Tom Coleman, USDA Forest Service]
For more information on this pest, infestation zones, and ways you can help limit the spread, see the University of California Goldspotted Oak Borer web site and UC IPM Pest Notes: Goldspotted Oak Borer.
[Text taken from the original article “Exotic Pests Invade California Landscapes” by Mary Louise Flint]