The Effect of X-ray Irradiation on the Fitness and Field Adaptability of the Codling Moth: An Orchard Study in Northeast China

Abstract

The codling moth, Cydia pomonella (L.), is an invasive agricultural pest of pome fruits and walnuts in China that threatens the apple industry in the Loess Plateau and Bohai Bay; it has developed resistance to many insecticides. Sterile insect technique (SIT) combined with area-wide integrated pest management (AW-IPM) can reduce the risk of resistance to insecticides and effectively control some insect pest species. Our previous laboratory experiment found that irradiation with 366 Gy of X-ray caused the males of the codling moth to become sterile. However, the sterility and adaptability of males after being irradiated with 366 Gy X-ray in the field are still unclear. In this study, we investigated the effect of X-ray irradiation on the fitness of male adults that emerged from pupae irradiated with 366 Gy to explore their adaptability and mating competitiveness, and to examine the effect of releasing sterile male insects in orchards in northeast China on the fruit infestation rate of the Nanguo pear. The results showed that 366 Gy of X-ray irradiation significantly reduced the mating competitiveness of males and the hatching rate of the eggs laid by females pairing with sterile males. Meanwhile, the lifespan of the sterile male moths was significantly shorter than that of the normal ones in the field. A pilot test showed that the release twice of sterile male moths in the orchards had no significant effect on the fruit infestation rate. Our field experiments provide a scientific basis for the further optimization of the SIT technology program for controlling C. pomonella.

Linalool fumigation improves mating competitiveness of males for population suppression of the global fruit pestCydia pomonella

“…In our recent studies, male C. pomonella pupae irradiated with 366 Gy of X-rays exhibited mating competitiveness indices of 0.001 in laboratory 13 and 0.0088 in orchards. 37 In this study, when subjected to 200 Gy of X-ray irradiation, the mating competitiveness index of sterilized male C. pomonella decreased, indicating a decline in mating competitiveness post-irradiation. Nevertheless, compared to the impact of 366 Gy irradiation, the mating competitiveness index of C. pomonella males following 200 Gy irradiation increased to 0.17 in laboratory conditions and 0.096 in orchards, suggesting that an optimized irradiation dose can enhance the mating competitiveness of sterile insects to a certain degree.…”