Sterility ofCydia pomonellaby X ray irradiation as an alternative to gamma radiation for the sterile insect technique

Abstract

The codling moth Cydia pomonella is a major pest of global significance impacting pome fruits and walnuts. It threatens the apple industry in the Loess Plateau and Bohai Bay in China. Sterile insect technique (SIT) could overcome the limitations set by environmentally compatible area-wide integrated pest management (AW-IPM) approaches such as mating disruption and attract-kill that are difficult to suppress in a high-density pest population, as well as the development of insecticide resistance. In this study, we investigated the effects of X-ray irradiation (183, 366, 549 Gy) on the fecundity and fertility of a laboratory strain of C. pomonella, using a newly developed irradiator, to evaluate the possibility of X-rays as a replacement for Cobalt60 (60Co-γ) and the expanded future role of this approach in codling moth control. Results show that the 8th-day is the optimal age for irradiation of male pupae. The fecundity decreased significantly as the dosage of radiation increased. The mating ratio and mating number were not influenced. However, treated females were sub-sterile at a radiation dose of 183 Gy (20.93%), and were almost 100% sterile at a radiation dose of 366 Gy or higher. Although exposure to a radiation dose of 366 Gy resulted in a significant reduction in the mating competitiveness of male moths, our radiation biology results suggest that this new generation of X-ray irradiator has potential applications in SIT programs for future codling moth control.

Side effects of X‐ray irradiation on flight ability of Cydia pomonella moth

“…This resulted in the moths receiving a dosage of 366 Gy of irradiation, as our previous investigation demonstrated that the application of 366 Gy of X-ray irradiation effectively induced complete sterility in male codling moths. 6,16 2.3 Flight ability 2.3.1 Flight performance of both genders of coding moth at different ages To determine the flight performance of male and female moth at different ages, we used the FXMD-24-USB insect flight information system (Henan Hebi Jiaduoke Industry and Trade Co., Ltd, Hebi, Henan, China). We kept the daily-emerging adult females and males separately in rearing boxes and fed them cotton balls in 10% honey water every day.…”

“…4 As one of the best-known representatives of tortricids that threaten the apple industry in the Loess Plateau and Bohai Bay, 5 this pest has been identified as an invasive alien species, and has been included in the key management list of invasive alien species issued by six departments including the Ministry of Agriculture and Rural Affairs of China. 6 Currently, various methods have been used to control C. pomonella, including agricultural, mechanical, chemical, and biological measures. 7 However, environmentally-friendly methods such as agricultural practices, pheromone-mediated mating disruption, and attract-kill have their limitations when dealing with highdensity of pest population.…”

“…15 In our previous study, we successfully employed X-ray radiation instead of 60 Co-γ radiation to administer a dosage of 366 Gy, which effectively sterilized male C. pomonella in laboratory and orchard environments. 6,16 Nevertheless, sterilization also resulted in a significant reduction in the mating competitiveness of male C. pomonella, a phenomenon that likely occurs across various insect species. 17 Consequently, comprehending the underlying mechanisms responsible for this decrease is crucial for optimizing programs utilizing SIT technology to manage C. pomonella.…”

“…Since the first report of the invasion of C. pomonella in Xinjiang Uygur Autonomous Region of China in 1957, 3 this pest has spread to 195 counties in Xinjiang, Gansu, Ningxia, Inner Mongolia, Heilongjiang, Jilin, Liaoning, Hebei, and Tianjin as of the end of 2021 4 . As one of the best‐known representatives of tortricids that threaten the apple industry in the Loess Plateau and Bohai Bay, 5 this pest has been identified as an invasive alien species, and has been included in the key management list of invasive alien species issued by six departments including the Ministry of Agriculture and Rural Affairs of China 6 …”

“…Though recent research has confirmed the suitability of X‐ray irradiation for controlling the Diptera species Ceratitis capitata and Anastrepha fraterculus 15 . In our previous study, we successfully employed X‐ray radiation instead of 60 Co‐γ radiation to administer a dosage of 366 Gy, which effectively sterilized male C. pomonella in laboratory and orchard environments 6,16 . Nevertheless, sterilization also resulted in a significant reduction in the mating competitiveness of male C. pomonella , a phenomenon that likely occurs across various insect species 17 .…”