Effects Of Diapause Genetic Regularity Of Asian Corn Borer(ACB),Ostrinia Furnacalis,and Its Influence On The Control Effect Of Beauveria Bassiana

In this study,aiming at the diapause genetic regularity of Asian corn borer（ACB）,Ostrinia furnacalis,and its control effect on Beauveria bassiana.The following experiments were conducted,The genetic structure of votine populations in the sympatric area and the dection of per and pdfr genes in the identification of ACB voltinism;Assessing the control effects of B.bassiana on the larvae of diapaused and non-diapaused ACB on artificial diets;Applying B.bassiana in greenhouse to control different voltine ACB.The main results were as follows:1.The population genetic regularity of ACB voltinism was detected using the mitochondrial COI gene and COII gene which were purified from ACB pupae that developed from the breaking diapaused overwinter larvae.Thirty-five and thirty haplotypes were identified in COI and COII genes respectively.There was one specific haplotype of COI gene linked to the univoltine population and there were 33 distinctive haplotypes of COI gene related to the bivoltine population.One specific haplotypes of COII gene were confirmed matched to the univoltine ACB population and 28 haplotypes were congruous with the bivoltine ACB population.The H35 of COI gene clearly sorted out the univoltine and bivoltine ACB populations,but COII gene did not clearly sort out the univoltine and bivoltine ACB populations.The per and pdfr genes of ACB pupae which were developed from the breaking diapaused overwinter larvae from Yitong and male ACB adults which were collected using pheromone lures in Gongzhuling were tested.Results showed that all the samples were bivoltinism.2.The mortality of ACB larvae on artificial diets under different diapause conditions was determined.In terms of B.bassiana treatment of diapause condition（8L:16D）compared with non-diapause condition（16L:8D）,it was found that diapause treating increased the mortality,pupating rate obviously and decreased the survival rate in the B.bassiana treatments of 1^st instar larvae;the diapause treating decreased the mortality and survival rate of the 3^rd instar larvae significantly,and increased the pupating rate significantly;diapause treating obviously reduced the mortality and survival rate of 5^thinstar larvae,and increased the pupation rate significantly.Compared with the treatment of B.bassiana under non-diapause conditions,the mortality of the 3^rd instar larvae under full darkness ascended significantly,and its survival rate and pupation rate were decreased significantly.3.In the simulated drought experiment in greenhouse,Beauveria bassiana granules and B.bassiana suspensions could reduce the damage of the 1^st or 2^nd generation ACB on sweet maize.It is proved that B.bassiana suspensions as endophytes can replace B.bassiana granules to control the 2^nd generation ACB on sweet maize.However,the control effect of B.bassiana suspensions was not significant effective when the 1^st and the 2^nd generations of ACB caused serious damage in the same field.In the future,it is promising to use the existing irrigation equipment to control the 2^nd generation ACB by root-irrigating with B.bassiana suspension.This study showed that root irrigation with B.bassiana suspensions could effectively control the 2^nd generation ACB;the diapaused status of O.furnacalis induced by short light had effects on the insecticidal activity of B.bassiana;there was a strong gene flow between the different voltine ACB populations in the sympatric area.