Lethal and sublethal impact of sulfoxaflor on three species of Trichogramma parasitoid wasps (Hymenoptera: Trichogrammatidae)

Sulfoxaflor is the first sulfoximine insecticide registered for controlling piercing-sucking pests in agricultural settings. Parasitoid wasps of the genus Trichogramma are effective biocontrol agents against a wide range of insect pests. In this study, we explored the impacts of sulfoxaflor on Trichogramma dendrolimi, Trichogramma ostriniae and Trichogramma confusum under lethal and sublethal-concentration exposure in laboratory. The acute toxicity WA indicated that sulfoxaflor possesses high toxicity to T. dendrolimi, T. ostriniae and T. confusum with LC(50)s of 0.12, 0.24 and 0.32 mg a.i. L-1, respectively. Parasitism of the three Trichogramma spp. were significantly impaired when the host eggs were exposed to low lethal concentrations of sulfoxaflor. The adult emergence rates of the subsequent generation of T. dendrolimi were compromised in all treatments. However, adult emergence rates of T. ostriniae and T. confusum were not profoundly affected at 0.0215 mg a.i. L-1. Results of IOBC categorization demonstrated that sulfoxaflor at 0.0215 mg a.i. L-1 was harmless to the parasitism of three Trichogramma spp., but being harmless to the adult emergence of their progeny at all WA concentrations. Overall, application of sulfoxaflor in association with T. dendrolimi, T. ostriniae and T. confusum should be carefully schemed in agricultural environments.