Abstract
The goldspotted oak borer,
Agrilus coxalis auroguttatus Schaeffer (Coleoptera: Buprestidae), is a new threat to several native oak species in California (CA) (Coleman & Seybold 2008a, b). The beetle larvae feed in and damage the outer xylem, cambium, and phloem of coast live oak,
Quercus agrifolia Née (Fagaceae), California black oak,
Q. kelloggii Newb., and canyon live oak,
Q. chrysolepis Liebm., killing these trees after several years of repeated injury. Infested trees can be identified by crown thinning and dieback, D-shaped adult emergence holes primarily on the main stem, and dark black or deep red staining on the bark exterior resulting from the wound response to the extensive larval feeding. The first record of
A. c. auroguttatus in CA is from 2004 (Westcott 2005), but the species was first linked with continuing tree mortality in CA in June 2008 (Coleman & Seybold 2008a, b). The invasive CA population is hypothesized to have been introduced from Arizona (AZ) during the mid- to late 1990s, most likely on firewood (Coleman & Seybold 2009, 2010). In support of this, the CA and AZ populations are considered to have identical subspecific status (Hespenheide & Bellamy 2009). The nominate subspecies,
Agrilus coxalis coxalis Waterhouse, is considered native to southern Mexico and northern Central America (Hespenheide & Bellamy 2009).
Citation
Coleman, T.W. ; Seybold, S.J. 2010. Verification of a useful character for separating the sexes of the goldspotted oak borer, Agrilus coxalis auroguttatus (Coleoptera: Buprestidae). Pan-Pacific Entomol. 86:58-62.
