## 4 Discussion  
These results demonstrated that the suppression of the development and reproduction of _P. operculella_ increased with increasing X-ray doses. The most radiotolerant stages were pupae and adults, and the most radiosensitive stage was eggs. Similar to our findings, [PERSON] et al. [28] reported that all stages of _Helicoverpa armigera_ and its reproduction were inhibited by X-ray irradiation. In the present study, the hatching rate of the \(F_{1}\) generation was investigated for pupae and adults, which means that the pupae and adults are generally studied to be more radiotolerant than the eggs and larvae [17; 18; 19]. Moreover, the population of emerged adults from the irradiated eggs and larvae was smaller than the irradiated pupae and adults. In addition, the emerged adults (female and male) were difficult to successfully populated that the mating timing of female and male are not right. So, the results were difficult to investigate until the next generation. While the research on the effects of ionizing energy on _P. operculella_ following X-ray irradiation is insufficient, many studies have been performed on gamma-rays [29; 30; 31; 32; 33]. Although gamma-irradiation was not performed in this study, [PERSON] et al. [33] reported that the gamma-irradiation of the eggs and larvae of _P. operculella_ at 120 Gy inhibited adult emergence and that emerged adults were deformed following gamma-irradiation at 80 Gy. In addition, [PERSON] et al. [29] reported that _P. operculella_ male adults irradiated with gamma-rays at 500 Gy showed no difference in mating ability from normal adults. However, other authors reported that the mating ability and frequency of mating decreased under 25 Gy of gamma-irradiation, and at 45 Gy, the sterility of _P. operculella_ male adults was 91% [31]. In addition, [PERSON] et al. [30; 32] suggested that 150 Gy of gamma-irradiation should be applied to completely control _P. operculella_. When X-ray irradiation was applied to the pupae, the lifespan of newly emerged adults was shortened as the dose increased. This result was similar to the results of a study on gamma rays [33]. The comet assay is likely to be used in genotoxicology and biological monitoring studies to detect DNA damage under various pest control strategies [34]. In this study, X-ray irradiation was shown to induce DNA damage in _P. operculella_ adults. The induction of DNA damage in insect pests irradiated with ionizing energy has also been observed in previous studies [17; 18; 19; 20; 23; 35; 36]. [PERSON] et al. [19] reported that DNA damage in _Spodoptera litura_ was not complete at electron beam irradiation doses of 100 Gy and above. However, the frequency of the ratios recorded at 30 and 50 Gy indicated repair to almost the same level observed in the control (0 Gy). In this study, DNA damage was not completely repaired 212 h after irradiation at a dose of 150 Gy or above. In addition, at doses of 50 and 100 Gy, irradiated adults were not repaired at 0 Gy. [PERSON] et al. [19] confirmed that DNA damage caused by low-dose irradiation (30 and 50 Gy) was repaired by multiple DNA repair systems and did not affect the hatchability of the \(F_{1}\) adults when irradiation was performed at low doses. In this study, the induction of DNA damage in _P. operculella_ adults by X-ray irradiation was confirmed only in females. However, according to the results reported in female and male _H. armigera_ adults exposed to gamma-irradiation, females showed higher radiotolerance than males, as males exhibited longer tail moments than females [20]. In addition, only the susceptibility of _P. operculella_ to X-rays was evaluated, and it is still necessary to perform an empirical evaluation, as in previous studies [21; 24; 25; 37; 38]. At quarantine sites, empirical tests for radiotolerant stages should be carried out, excluding inspection for pupal and adult insects that can be seen with the naked eye [39].