Impact of biological control agents on Canadian emerald ash borer parasitoids

Three biological control agents have been released in Canada for the control of emerald ash borer. These species were released as part of the US-lead effort to reduce the impact of the pest on ash trees in North America. The first releases of Tetrastichus planipennisi were made in 2013 with Oobius agrili and Spathius galinae following in 2015 and 2017. Beginning in 2018 we initiated experiments to examine the impact and dispersal of these parasitoids in the Canadian ash ecosystem. These experiments were intended to determine if the parasitoids were contributing to population regulation, and to determine if and how far the insect has spread. To examine the impact of the parasitoids on population dynamics we used a series of sequential caging studies to partition the attack of parasitoids on resident emerald as borer in some of the oldest release sites. In our dispersal experiment we used pan traps established at 2-30 Km from the oldest release sites to examine dispersal in southwestern Ontario, Canada. The results of these experiments will be used to estimate the contribution of these biological control agents to regulation of emerald ash borer in Canada.