Hymenopteran Parasitoids Attacking the Invasive Emerald Ash Borer (Coleoptera: Buprestidae) in Western and Central Pennsylvania

We conducted field surveys of the emerald ash borer (EAB), Agrilus planipennis Fairinaire, and associated larval parasitoids in western and central Pennsylvania (Cranberry Township in Butler County and Granville in Mifflin County) in the spring and fall of 2009. The survey procedure involved destructively debarking sections of the main trunk (bole) of EAB-infested green ash (Fraxinus pennsylvanica Marsh.) trees from the ground to the height of 2 m. Three species of the hymenopteran parasitoids were consistently recovered from EAB larvae observed in both survey sites, including two indigenous species of braconids, Spathius laflammei Provancher (= Spathius benefactor Matthews) and Atanycolus nigropyga Shenefelt and the exotic (accidentally introduced) eupelmid Balcha indica (Mani & Kaul). In addition, there are three unidentified species of hymenopteran parasitoids including two braconids Atanycolus sp. [possibly Atanycolus disputabilis (Cresson)] and Spathius sp. (at the Butler Co. site) and one ichneumonid Dolichomitus sp. (at the Mifflin Co. site). These parasitoids together parasitized 0.5-4.6% and 0.5-1.5% of the sampled EAB hosts at the Butler and Mifflin Co. sites, respectively. Parasitism rate by each species or group of those hymenopteran parasitoids varied between the two survey sites-with parasitism rates being generally higher at the Butler Co. site than at the Mifflin Co. site. Studies are needed to determine if those new associations of North American indigenous braconid parasitoids with EAB may play a complementary role in controlling this invasive