Proactive assessment of a native North American egg parasitoid, Anastatus reduvii (Hymenoptera: Eupelmidae), as a potential biological control agent of Lycorma delicatula (Hemiptera: Fulgoridae), in California

• Anastatus reduvii is native to and widespread in North America and easy to rear. • Anastatus reduvii parasitized 79% of L. delicatula egg masses, with a 31% parasitism rate. • Exposure to A. reduvii reduced hatch of L. delicatula from 90% to 33%. • Rearing A. reduvii on different hosts did not significantly affect its performance. The spotted lanternfly, Lycorma delicatula , native to parts of East Asia and the Indomalayan region, is a polyphagous herbivore poised to become a major global agricultural pest. Since its establishment in the US in 2014, L. delicatula continues to expand its range, and its invasion into California is highly anticipated. Proactive work evaluating Anastatus orientalis , an egg parasitoid of L. delicatula in its native range, as a potential biological agent determined this parasitoid is too polyphagous for release in the US, and no other suitable egg parasitoids have been identified. Consequently, the potential of native North American egg parasitoids to provide biotic resistance to the L. delicatula invasion is being assessed. In a quarantine laboratory study, Anastatus reduvii, an egg parasitoid native to and widespread in North America, including California, parasitized 79% of L. delicatula egg masses with an average egg parasitism rate of 31%. Egg masses exposed to A. reduvii exhibited significantly reduced L. delicatula hatch rates (33%) compared to unexposed control egg masses (90%). These observed rates are comparable to that of A. orientalis attacking L. delicatula egg masses. Rearing A. reduvii from eggs of five different host species did not significantly affect parasitism or L. delicatula mortality, although parasitism was substantially higher compared to previous work using A. reduvii reared exclusively on Pentatomidae eggs. Mass-rearing of A. reduvii is highly feasible and continued investigations into the suitability of this egg parasitoid as a biological control agent for L. delicatula in the US are recommended.