Dieback
Guides
Agrilus pseudocoryli
hazel stem borer
Agrilus pseudocoryli is a metallic wood-boring beetle in the family Buprestidae, commonly known as the hazel stem borer. It develops within stems of hazelnut plants (Corylus spp.), where larval tunneling causes dieback. The species has been documented as a pest of hybrid hazelnut cultivars in the Great Lakes region, with damage severity varying by cultivar. Adult activity occurs from early June to mid-July.