Reproductive biology of the newly introduced emerald ash borer egg parasitoid, Oobius agrili, in the Mid-Atlantics
Date
2018
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Publisher
University of Delaware
Abstract
Oobius agrili (Hymenoptera: Encyrtidae) is a solitary egg parasitoid native to northeast Asia. It has been released in the United States since 2007 for biocontrol of invasive emerald ash borer (EAB) Agrilius planipennis (Coleoptera: Buprestidae). In order to develop a sound field release strategy that enhances the probability of its establishment in Mid-Atlantic area. We here evaluate the potential impacts of different releasing times and parasitoid diapause status on the reproductive biology of this introduced biocontrol agent under field conditions in Susquehanna State Park in northwestern Maryland. ☐ Vials were placed on the trees either early or late in the season with parasitoids that were either previously diapaused or non-diapaused. We measured the emergence, longevity, parasitism, and diapause of the subsequent generations. Early releases of both types of O. agrili produced fewer progeny in diapause, allowing for greater parasitism throughout the season. Non-diapaused adults are more likely to produce diapaused eggs than diapaused adults, regardless of release time. To learn more about the O. agrili’s lifecycle, we studied the overwintering behavior of both diapaused and non-diapaused populations of O. agrili in field cages in three climatically unique locations in the mid-Atlantic states. The study showed low mortality among overwintering parasitoids, regardless of year or field site. The timeline for O.agrili showed varied emergence between the three sites. The results of this study will help to determine how to better use this parasitoid for the control of A.plannipennis in mid-Atlantic states.