Study On The Inheritance Of Resistance And Biological Fitness Of Blattella Germanica To Cypermethin

Blattella germanica is hardest control as an urban health pest worldwide distribution，whichharms to human life and the environment seriously. Blattella germanica is always the target ofinsectis control, however, the current means of prevention mainly through pesticides or chemicalcontrol. Significant resistance is found in many countries and locations with a large number ofuse of pesticides, so that the epidemic prevention work has increased the difficulty of it.Therefore how to control the Blattella germanica has become an urgent problem to be solved.Timely and accurately determining the occurrence, level of resistance and the pace of developmentof Blattella germanica and basing on this new approach form a new point of research on a newmethod and technology of eliminating Blattella germanica will help to make scientific andrational control strategies and help to research the study of the mechanism of toxicity ofpesticides. In the study of resistance, inheritance of resistance and biological fitness are basis tostudy the development of resistance and to solve problems.This study was based on susceptible strains(SS) and resistant strains(RR) of Blattellagermanica to cypermethrin for the study. Firstly, the Blattella germanica were breeded bycypermethrin; Then studied the Blattella germanica inheritance of resistance to cypermethrin, andhybridization strains relative fitness; Also studied the resistance impact of hybridization tocypermethrin、propoxur、dichlorvos and showed the recession without drug selection pressure forresistance; Finally, discussed the control strategies from the perspective of inheritance ofresistance and biological fitness, then providing new ideas and methods for the Blattellagermanica treatment. The main contents and results are as follows:(1) Blattella germanica breeded for resistance to cypermethrinFirstly resistant screening was conducted with15ppm concentration of cypermethrin onBlattella germanica in this study, cultivating resistant strains. Though comparing the resistantstrains and the susceptible strains found that LC50increasing from the original susceptible strainsof5.295ppm to21.202ppm, resistance ratio incresing4.004times.(2) The inheritance of resistance of Blattella germanica to cypermethrinThe Blattella germanica were hybrided by the orthogonal and reciprocal cross of sensitivestrains and resistant strains, analysising the inheritance of resistance to cypermethrin. The resultsshowed that the LD-P(log dose mortality probit) lines of the orthogonal(RS) lines and anti-cross(SR) lines of Blattella germanica to cypermethrin were basically the same slope, andthe male and female ratio closed to1:1, so the inheritance of resistance of Blattella germanica tocypermethrin was autosomal; The dominant D values of orthogonal lines and anti-cross lines ofBlattella germanica to cypermethrin were0.236and0.279between0-1, so the resistance genewas not completely dominant inheritance; Experimental results showed that the measuredresponse curve of BC-generation(Backcross) to cypermethrin in mortality of50%, F2generationto cypermethrin in mortality of25%,75%had no significant level at the slope, andΣχ2(BC)12.3378, Σχ2(F2)37.6869were greater than Σχ2(0.05)11.07, so the resistance gene waspolygenic.(3) The biological fitness of Blattella germanica to cypermethrinComparing the growth and reproductive characteristics of anti-cypermethrin Blattellagermanica strains, susceptible strains and hybridization strains, the results showed that the podspawning time, the egg pod off time, hatching egg pod, number of larvae hatching, egg podlength and width, larval emergence rate, developmental period, the proportion of male andfemale of Blattella germanica had obvious disadvantage, fitness decreasing by62%. A varietyof biological fitness of hybridization strains were between sensitive and resistant strains, andopositive and negative hybridization fitness were0.79,0.74respectively.(4) The impact of hybridization reaction to Blattella germanicaRR, SS, RS, SR, BC and F2strains of Blattella germanica tested by cypermethrin、propoxurand dichlorvos, the results showed that the KT50of hybridization strains of Blattella germanicawere lower than resistant strains, indicating that the hybridization strains of Blattella germanicahad low resistance, and hybridization had an impact on resistance, while this experiment alsoverified the resistance recession without drug selection pressure.(5) Prevention stragegies of Blattella germanicaThrough the study of inheritance of resistance and biological fitness of Blattella germanicastrains to cypermethrin thought that Blattella germanica was easy to hybrid in areas withoutgenerate resistance, low cross-resistance drug should be used in areas without generate resistance;No cross-resistance drug should be used in the area of resistance. This study provided the basiswheeling with pesticides and suspending and making timely adjustments for confrontationalstrategy, providing new theories, new prospects for the Blattella germanica control.