Sensitivity of the Egg Parasitoid Trissolcus japonicus (Hymenoptera: Scelionidae) to Field and Laboratory-Applied Insecticide Residue

The spread of adventive Trissolcus japonicus (Ashmead, 1904) populations in North America is anticipated to increase biological control of Halyomorpha halys (Stal; Hemiptera: Pentatomidae), the brown marmorated stink bug. In an agricultural context, biological control will succeed if it can be integrated in an environment with insecticide applications. We investigated T. japonicus compatibility with nine conventional and organic insecticides commonly used in integrated pest management in perennial crops. Through evaluating mortality and longevity in field and laboratory trials, we determined that T. japonicus fares poorly when exposed to residues of neonicotinoids and pyrethroids. Spinosad resulted in the highest percentage of T. japonicus mortality, 100% in the laboratory and 97% in a field trial. The anthranilic diamide, chlorantraniliprole, had the lowest lethality, with no differences compared to an untreated control. Trissolcus japonicus survived insecticide applications in hazelnut orchards, and over 50% of wasps remained alive after contact with the anthranilic diamides, chlorantraniliprole and cyantraniliprole, the biopesticide Chromobacterium, and an untreated control. Our results indicate that T. japonicus is unlikely to survive and parasitize H. halys in settings that coincide with broad-spectrum insecticide application. Future T. japonicus redistributions could continue in orchards treated with anthranilic diamides and Chromobacterium. As H. halys is a landscape-level pest, orchards may also benefit from biological control if T. japonicus are released in unsprayed areas adjacent to agriculture and in urban sites.