The Asian chestnut gall wasp, Dryocosmus kuriphilus (Hymenoptera: Cynipidae), is a globally invasive pest of Castanea. Population regulators and geographic range expansion of the Asian chestnut gall wasp in North America with focus on natural enemy recruitment have been evaluated. After the initial discovery of the gall wasp in the U.S., there were biological control releases that included Megastigmus sp., Torymus sp., T. beneficus, T. koreanus, and T. sinensis. Of these introduced parasites, only T. sinensis has been recovered definitively. However, eight additional native parasitoid species have been collected in association with the gall wasp, some in great enough numbers to help regulate populations.