The sterile insect technique as a novel management tool for control of pepper weevil (Anthonomus eugenii Cano) in greenhouse and field pepper crops

The pepper weevil (PW; Anthonomus eugenii Cano) is a significant pest of pepper crops in North America, associated with up to 50% crop losses in severe infestations, and together with PW management, result in millions of dollars in economic damage annually. Larvae develop entirely within pepper buds and fruit causing premature fruit drop. This cryptic lifestyle also means that insecticide sprays are generally ineffective for managing PW, which is exacerbated by resistance in this species. Furthermore, no biocontrol agent targeting PW is currently commercialized. The sterile insect technique (SIT) is a novel approach to PW management, though it is an established method used to control a diversity of other pests worldwide. This foundational study focuses on producing high-quality sterile male insects for a PW-SIT system. We showed that 100% of late-instar PW pupae of both sexes irradiated at 110 Gy of gamma radiation failed to produce adult offspring, and egg sterility was >97%. The longevity of irradiated weevils was shorter than non-irradiated weevils, though it may be sufficiently long for a viable PW-SIT system. Of relevance is that irradiated males produced significantly less sperm than non-irradiated controls, and their ability to compete for mates in a field cage test was also impacted. Finally, flight activity was also decreased in irradiated insects, but not completely absent. Taken together, this study suggests a PW-SIT program may be feasible, and lays the groundwork for development of a sustainable new tool for PW suppression both in field and greenhouse pepper crops.