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.
For more information on this pest, infestation zones, and ways you can help limit the...
- Author: Akif Eskalen
[From the August 2015 issue of the UC IPM Green Bulletin]
Declining coast live oak (Quercus agrifolia) trees have recently been found throughout urban landscapes in Los Angeles, Orange, Riverside, Santa Barbara, Ventura and Monterey counties. A fungus associated with a specific beetle is causing the decline by spreading what is known as “foamy bark canker disease” (Figures 1 and 2).
The fungal species, Geosmithia pallida, was recovered from symptomatic plant tissues in association with the western oak bark beetle.../span>