## 4 Discussion  
Based on this study, we confirmed that electron beam irradiation almost equally inhibits the normal development and reproduction in acaricide-resistant and susceptible strains of two-spotted mites. _Tetranychus urticae_ is usually controlled by pesticides and exhibits a characteristic resistance associated with its short life cycle. In this study, we investigated the effect of electron beam irradiation on the egg, protonymph, and adult stages of _T. urticae_ strains with 100-, 700-, and 5,000,000-fold greater resistance than the susceptible strain to acequinocyl, bifenazate and etoxazole, respectively. It has been reported that even though the electron beam is less penetrative than gamma rays, it can effectively control insect pests and prevent decay when used on cereals, nuts, spices, dried vegetables, tea leaves, and a few types of germinating seeds [16,17]. A previous study also reported that insect pests resistant to insecticides exhibit resistance to ionizing radiation. According to [PERSON] et al. [11], _R. dominica_ exhibiting resistance to a phosphine fumigant was more highly resistant to electron beams and gamma rays than the susceptible strains of _R. dominica_. Another study showed that phosphine-resistant strains of _Tribolium castaneum_ (Herbst) (Coleopterara: Tenebrionidae) were more tolerant to gamma rays compared with a susceptible strain [18]. Phosphine induces the formation of reactive oxygen radicals, which also generate other radical species [19]. It has been reported that phosphine-resistant insects with mechanisms to prevent oxidative damage also exhibit resistance to electron beams. Therefore, in this study, we investigated whether acaricide-resistant _T. urticae_ also exhibited resistance to electron beam irradiation. As a result, there were some differences between the resistant and susceptible strains of _T. urticae_, but these did not significantly affect the overall conclusion. The hatching rate of eggs of all strains of _T. urticae_ decreased with increasing electron beam irradiation dose. Hatching was suppressed completely at 150 Gy. The number of eggs laid by adults (successfully hatched) of BR, ER, and S strains of _T. urticae_ decreased as the irradiation dose increased; however, when the AR strain was irradiated with 50 Gy, the number of eggs increased and then decreased again at 100 Gy, suggesting a resurgence of the insect pests. We confirmed that the emergence of adults from irradiated nymphs was not significantly affected by electron beam irradiation except for the AR strain at 300 Gy. In addition, at 200 Gy, the longevity of the ER strains decreased significantly, but there was no significant difference in the other groups. Although significant results were obtained for each group, the goal of our study was to determine whether acaricide-resistant mites were also resistant to electron beam irradiation. From this point of view, there were no significant results overall. In our previous study results, there was no effect of electron beam irradiation on the susceptible and insecticide-resistant cotton aphids [20]. Figure 1: Changes in the expression of _T. urticae_ proteins induced by electron beam irradiation. Protein was harvested from the S, AR, BR, and ER strains at 2, 4, and 6 days after electron beam irradiation (400 Gy) and analyzed by 10% SDS-PAGE. M, protein size marker; S, susceptible strain; AR, acequinocyl-resistant strain; BR, bifenazate-resistant strain; ER, etoxazole-resistant strain. Since electron beam irradiation induces abnormal reproduction and development in insect pests depending on the insect species and stage of development, a large amount of basic data is required for ionizing radiation to be utilized for quarantine disinfection.