Using molecular techniques to guide the management of the invasive goldspotted oak borer Agrilus auroguttatus schaeffer (Coleoptera: Buprestidae)

The goldspotted oak borer (Agrilus auroguttatus) is a buprestid beetle which is native to oak woodlands in southeastern Arizona. The goldspotted oak borer’s introduction into southern California has caused widespread mortality to three species of native California oaks. This beetle was probably introduced into southern California via the movement of infested oak firewood, and since 2002, tree mortality from A. auroguttatus has been conservatively estimated at >21,500 trees. However, A. auroguttatus is not a pest in its native range. The disproportionate levels of attack by A. auroguttatus in its native and introduced range suggests that a classical biological control program with co-evolved host specific parasitoids can potentially be a permanent, low cost, environmentally safe, and pest-specific management strategy for this invasive beetle. The development of an effective classical biological control program requires several components such as basic life history information on the pest, and the identification of host specific natural enemies from the pest’s area of origin. The use of DNA-based techniques has the potential to identify the area of origin for California’s invasive population. Identification of this area within the native range of goldspotted oak borer could facilitate the collection of natural enemies that have evolved to exploit the genotype of the invading pest population. Preliminary results from our molecular analyses suggest that the Dragoon Mountains in Arizona is a likely source of the California population. However, further collections are necessary in order to definitively pinpoint the geographic source of the California population of A. auroguttatus.