Effect Of Irradiation On The Fecundity Of Grapholita Molesta

The oriental fruit moth,Grapholita molesta is an important fruit tree pest,which poses a serious economic threat to the fruit industry such as pears and peaches.Agricultural,physical,biological,and chemical control methods are widely used in the prevention and treatment of G.molesta,but these prevention and control measures have varying degrees of defects in terms of control effect and environmental friendliness.The sterile insect technique（SIT）can effectively overcome the shortcomings of the above prevention methods.In order to evaluate the application potential of SIT technology in the control of G.molesta,this study first carried out an indoor experiment and analyzed the influence of traditional radioactive ⁶⁰Co-γrays on the reproduction of G.molesta.On this basis,the analysis was more than ⁶⁰Co-γrays.In order to provide a safe alternative source（X-ray）on the reproductive ability,lifespan,flight ability and mating competitiveness of G.molesta,and provide a theoretical basis for the further use of SIT technology based on irradiation in the field to control G.molesta.The main results are as follows:Compared with the control group,⁶⁰Co-γrays of different irradiation doses（0,25,50,75Gy）irradiated male pupae 1 day before emergence,and there was no significant difference in adult emergence rate among the treatment groups,indicating that irradiation has no significant effect on the emergence rate.Compared with the control group,there was no significant difference in the number of eggs produced per female and the mating rate of male moths that had been irradiated at 25 Gy,50 Gy,and 75 Gy after mating with normal female moths.As the irradiation dose increased,the hatching rate of the irradiated group gradually decreased.Compared with the control group,with the increase of the irradiation dose,the average life span of the males in the irradiation group decreased to varying degrees.The effect of 67 Gy and 133 Gy X-rays on the emergence rate of male pupae of G.molesta at different ages（2 d,5 d,8 d）shows that 8 days of age is the most suitable pupal age for irradiation,and there was no significant difference in pupa emergence rate compared with the control group.After 67 Gy and 133 Gy irradiated male pupae,the number of single female eggs and the hatching rate of eggs after the emergence of male moths and normal female moths were significantly lower than those of the control group.The life span of male moths in the 67 Gy and 133 Gy irradiation treatment groups was significantly shorter than that of the control group.As the irradiation dose increased,the mating rate gradually decreased.The mating rate of male moths irradiated by 133 Gy was significantly different from that of the control group.Irradiation has no significant effect on the mating frequency of male moths and female moths,but the average daily egg production of female moths in the irradiated group after mating is significantly reduced compared with the control.The higher the radiation dose,the smaller the change in daily egg production.The spawning period is also significantly shortened.There was a significant difference in the number of eggs laid by females between the control group and the 67 Gy and 133 Gy irradiated groups on the 3rd to 10th days.There was no significant difference in the number of eggs laid by the females in the 67 Gy and 133Gy irradiation groups.Irradiation has no obvious effect on the flight ability of male moths after emergence,but the mating competitiveness of its male moths is reduced.Both X-ray and ⁶⁰Co-γ-ray irradiation reduced the reproduction-related parameters of G.molesta,indicating that both types of rays have the potential to be used in the control of G.molesta,and X-rays can theoretically replace ⁶⁰Co-γrays for prevention and control of G.molesta,this research result provides theoretical guidance for further optimization of irradiation conditions and the use of SIT technology to control G.molesta.