Study On The Way Of Transmission Of Myzus Perscae And The Aphids Control By Using Of Fungi

In this study,Myzus persicae was used as the research object.On the basis of the identification of the toxic sources collected in the southern Anhui tobacco area,the relative expression of CMV in the stylet,head and abdomen of aphid was detected by fluorescence quantitative PCR?qRT-PCR?.Determine the time of virus holding and the efficiency of transmission,and made sure the way of transmitting CMV subgroup IB by aphids.At the same time,10 strains of entomopathogenic fungi were tested the virulence of Myzus persicae nymph,and 2 strains with high virulence to Myzus persicae nymph were screened.The main research results are as follows:1.Identification of toxic sources:Suspected tobacco leaves infected CMV were collected from the southern Anhui Tobacco Area?Huangdu Village and Shitian Village,Xuancheng City,Anhui Province?.Only three invaders were identified infection only by CMV.In addition,three strains were compound infection with TMV and CMV.By sequencing,the CMV CP sequences were compared.The six CMV samples were all CMV belong to subgroup IB.2.Detection of toxic conditions in various parts of the aphids:qRT-PCR was used to detect the virus in the stylet,head,and abdomen of the aphids,and the stylet,head,and abdomen of the aphids were detected.Among them,the highest rate of CMV in stylet was100%,followed by the rate of 88.89%in the head and 50%in the abdomen;3.The duration of aphid holding virus and its transmission efficiency:The aphids were fed with tobacco plants which infected with CMV,the rate of contain CMV gradually decreased with the prolongation of time,at the first 2 hours,the rate of infection was 62.5%,the rate of infection was 25%at 10 h.No virus was detected at 12 h and the duration of contain CMV was up to 10 h.The virus transmission efficiency at each time point was measured.The efficiency of virus transmission increased first and then decreased with time.Aphids were inoculated to healthy tobacco seedlings immediately after feeding,the incidence rate of tobacco seedlings was approximately 17%.When the aphid was treated with starvation for 6 hours,it was inoculated to the healthy tobacco seedling.The incidence of tobacco seedling was the highest?nearly 60%?.The 10 h after the treatment of aphid hunger was inoculated into healthy tobacco seedlings,the incidence of tobacco seedlings was about 15%.From the above results,the efficiency of the transmission of the aphids was not directly proportional to its poisoning rate.4.Screening of pathogenic fungi with high toxicity of aphids:Two strains of Beauveria bassiana Bb21 and B1 were screened out from 10 strains of entomopathogenic fungi,which were highly virulent to the aphid.The fatality rate was more than 90%and the rate of cadaver was 70%at high concentration of 1×10⁸ spores/mL.The mortality of strain B1was the highest,with LT₅₀ of 2.66 d at high concentration and LC₅₀ of 8.91×10³ spores/mL on day 7.The next strain was Bb21,with LT₅₀ of 4.99 d at high concentration and LC₅₀ of8.32×10⁴ spores/mL on day 7.And the higher the spore liquid concentration of the same strain,the higher the mortality.In the biological control of Myzus persicae,B1 and Bb21can be considered as important biological control materials.