Oak-mortality
Guides
Agrilus auroguttatus
Goldspotted Oak Borer
Agrilus auroguttatus, the goldspotted oak borer, is a jewel beetle native to southeastern Arizona that became invasive in southern California around 2004. In California, it has caused extensive mortality in oak forests, killing an estimated 80,000 trees, primarily affecting red oaks. The species exhibits significantly higher population densities in its invasive range compared to its native range, where it coexists with a more diverse community of native borers. It was previously treated as a subspecies of Agrilus coxalis but is now recognized as a distinct species.
Agrilus bilineatus
two-lined chestnut borer, twolined chestnut borer
Agrilus bilineatus is a metallic wood-boring beetle native to eastern North America that attacks oak trees (Quercus spp.) and chestnut (Castanea spp.). Unlike most Agrilus species that develop in dead twigs and branches, it is a trunk borer of living trees and represents a significant forest pest. Adults emerge from June through September with peak activity in late June to July. The species has been introduced to Turkey, where it poses an emerging threat to European oak and chestnut species.