Drosophila suzukii (Matsumura) is an invasive global pest of small soft-skinned and stone fruits in the United States. The entomopathogenic nematode (EPN), Steinernema carpocapsae, is a promising biological control agent of SWD. Past studies suggest that EPNs can suppress SWD pupal emergence; however, many aspects of EPN applications are still under investigation to ensure applications are indeed practical to implement in the field. In this study, we were interested in investigating two understudied aspects of EPN applications for targeted control of SWD: (1) EPN compatibility with pupal parasitoid wasps of SWD, and (2) EPN virulence against SWD once applied through drip irrigation lines commonly used by caneberry growers in California. To determine if EPNs would adversely affect the survival of the pupal parasitoids Trichopria drosophilae and Pachycrepoideus vindemmiae, repeated sand petri dish bioassays were performed. A series of experiments was also conducted to evaluate EPN distribution, deposition, and infectivity of SWD following delivery through drip irrigation systems. To our knowledge, this study is the first to test whether field-applied EPNs can infect SWD. Our results suggest that simultaneous use of EPNs and pupal parasitoids may result in greater overall pest suppression of SWD mid-stage pupae, however, EPNs can negatively impact adult wasp emergence. Furthermore, EPNs applied through drip irrigation were shown to infect SWD mid-stage pupae. Thus, drip irrigation should be considered a practical option for executing EPN applications targeting SWD in soil
