Overwintering developmental stages of emerald ash borer in North Carolina

The invasive woodboring beetle emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) first was detected in the US in 2002 near Detroit, Michigan, USA. Since then it has continued to expand its range into the southern and midwestern sections of the country. Emerald ash borer was discovered in North Carolina, USA, in 2013, and is currently reported from more than 60 counties in the state. The present study was undertaken to begin determining the phenology of emerald ash borer in its newly expanded range below 40 degrees N latitude in North America. Here we report 4 yr of data on the overwintering stages of emerald ash borer in north-central North Carolina, obtained by debarking infested trees harvested from a single site near the northern border with Virginia, USA, with 1-yr additional data from a site about 39 km away. Results indicated that most emerald ash borers overwinter as fourth instars, with a small proportion advancing to the J-larva stage. Parasitoids that emerged from cocoons collected from emerald ash borer galleries and from logs held in emergence cages also were identified. These Hymenoptera include specimens of Xorides (Exomus) humeralis (Say) (Ichneumonidae), Atanycolus cf. cappaerti Marsh and Strazanac (Braconidae), Balcha indica (Mani & Kau) (Eupelmidae), Spathius sp. Nees (Braconidae), and Wroughtonia sp. Cameron (Braconidae).