Parasitoids and associated insects emerging from trees colonized by native Agrilus in Wisconsin

We examined parasitoids and other co-occurring insects associated with three native Agrilus species, twolined chesnut borer (Agrilus bilineatus), bronze birch borer (Agrilus anxius), and bronze poplar borer (Agrilus liragus), in Wisconsin. Wisconsin is on the western leading edge of the invasive Emerald ash borer, Agrilus planipennis, and has at least two established populations. Research in other areas has shown that some native natural enemies can cause mortality to A. planipennis, so our objective was to generate baseline data that could help both gauge this potential and evaluate potential nontarget effects of various control programs. Infested Quercus rubra, Quercus robur, Betula papyrifera, and Populus tremuloides were felled during the summers and falls of 2010 and 2011 from various locations throughout Wisconsin. Trees were sectioned into approximately 0.76-0.91 meter lengths, and the ends were waxed to prevent desiccation. Logs were stored at ~4 ¡C until transferred to rearing containers starting in January 2012 and ending in July 2012. Rearing containers were held at approximately 27 ¡C. Emerging insects were collected daily for 4 months and identified. After emergence had terminated, the bark was removed, and the presence and size of Agrilus galleries, and parasitism, were quantified. Additional laboratory studies were performed to identify sources of volatiles that influence orientation of parasitic wasps.