The oriental fruit moth, Grapholita molesta  Busck, is a major pest of fruit trees worldwide, it is necessary to develop green control technology instead of the traditional chemical pesticide. Although the sterile insect technique (SIT) is a safe and effective method for controlling G . molesta , the high cost of mass rearing irradiated pupae hinders its widespread adoption. In this study, we identified the optimal sub-sterilizing X-ray dose for G . molesta  adults and evaluated its effects on the mating competitiveness of males, growth and reproduction of the F 1   generation population, and the sterility rate of field- caught males. The results showed that the sub-sterilizing dose of 1-day-old male was 130 Gy, which rendered most males sterile (76.34%) and females nearly sterile (97.41%). Moreover, the sterile trait of the male parents that had been irradiated with 130 Gy of X-rays was successfully transmitted to the F 1   generation, whose sterility rate (84.13–93.61%) exceeded that of F 0   males. The F 1   generation population exhibited significantly lower values for the net reproductive rate (R 0 ), intrinsic rate of increase (r ), and finite rate of increase (λ ) compared to the non-irradiated group. Furthermore, the competitive mating index and sterility rate of irradiated males were the highest when they were paired with unirradiated males and females at a release ratio of 20:1:1. The irradiating wild males captured by sex pheromones in peach orchards with the sub-sterilizing dose achieved a 75.69% sterility rate, comparable to the laboratory-reared population. This study introduces a novel X-ray irradiation method for adult G . molesta  captured in the orchard field and lays a theoretical foundation for promoting the wide application of the SIT.

Grapholita molesta  /  sterile insect technique (SIT)  /  X-ray  /  sub-sterilizing dose  /  mating competitiveness