Research Of Resistance Mechanisms Of Blattella Germanica To High Effect Cypermethrin And Management Policy

Acting as one of the vital vetor insects in the world, Blattella germanica has invaded our country strongly and strongly since 1990s. At present, medical management is main measure to control population number of vetor insects. Since 1980s, being a new kinds of insecticide, Pyrethroid insecticides have been widely used in pest management in agriculture, forestry and family. But a lot of insects have developed resistance to Pyrethroid, pesticide resistance has been a critical restrictive factor for medical management of many vetor insects. Recently medical management and researchs relative to cockroach, for example Blattella germanica, have been more and more conspicuous. The rapid and accurate determination of occurrence and development of resistance and resistance level is very significant to establish reasonable management policy. At the same time, researchs of toxicity mechanism of insecticides and rapid and accurate determination methods are the base of the work.The texts took Blattella germanica susceptible strain as research object and refered to the method of GB 13917.1-13917.8—92 for insecticide registered testing indoor effect. What more, we did some improvement in some ways. We determined five low lethal concentrations of high effect cypermethrin that their lethal rates were not more than 30% through many experiments. Firstly, we observed the influence of different concentration insecticide on action and death-rate of Blattella germanica susceptible strain. The test results displaied that high effect cypermethrin can intensively influence equilibrium and action capability of Blattella germanica susceptible strain and had intensive lethal effect that showed concentration-effect correlation.Secondly, we determined acetylcholinesterase (AChE) , Superoxide dismutase(SOD) , Na-K-ATP_ase, Ca-ATP_ase and Glutathione peroxidase (GPX) activities of Blattella germanica susceptible strain when we sprayed quantitative high effect cypermethrin of different concentration on them for 24hours, 48hours, 72hours, 96hours, 120hours and144hours in laboratory, so that we could thoroughly research the operational mechanisms of high effect cypermethrin and the dosage effect and the time effect correlation between high effect cypermethrin and different enzymes' activities of Blattella germanica. The results showed AChE, SOD, Na-K-ATPase, Ca-ATP^e and GPX were all one of the targets of high effect cypermethrin. After we analysed the results of these enzymes' activities we could find that high effect cypermethrin had apparently inhibitory effect on AChE, Na-K-ATPase and Ca-ATPase and the results showed the dosage effect and the time effect correlation between them. At the same time, we could see high effect cypermethrin had apparently inductive effect on SOD and GPX and not only the correlation of the inductive intensition and the concentration of high effect cypermethrin was positive relationship for some degree but also the inductive time effect of high effect cypermethrin of different concentration was different. The variety of different enzymes' activities in time order imply that we must consider insecticide resistance and pesticide tolerance questions when we use high effect cypermethrin. We should reasonably control insecticide concentration of our using and scientifically establish spraying time in order to prevent resistance of Blattella germanica and prolong usable life of insecticides.Thirdly, field strains of Blattella germanica were captured from JiNa^ QingDao and DongYing and compared with susceptible strain. I discussed the senses and utilization of the indexs of molecule toxicology in factually resistant monitoring. The results showed AChE, SOD and GPX activities were effective indexs of resistant monitoring and Na-K-ATPase and Ca-ATPase activities can only be reference indexs. Determining structure variation of Na-K-ATPase and Ca-ATPase or their genes may be more effective than their activities, but it need more researchs.The experiments may perfect the operational mechanisms researchs of high effect cypermethrin and the resistant mechanisms researchs of Blattella germanica to high effect cypermethrin in order that we can provide theoretical basis and useful methods for management of Blattella germanica. There were some reports relative to the correlation between insect resistance and different enzymes' activities in domestic and foreign papers and magazines, but the effect and operational mechanisms of higheffect cypermethrin on AChE, SOD, Na-K-ATPase, Ca-ATPase and GPX of Blattella germanica and the correlation between these enzymes' activities and resistance of Blattella germanica have few or no reports. Especially, there aren't such systemic research reports as ours in our country for the present. It may be that we only care much about resistance of Blattella germanica because their invasions are strongly and strongly for recent years. It can say that my research fruits are advanced in domestic researchs. Of course, in the resistant mechanisms researchs of Blattella germanica to high effect cypermethrin, some molecule toxicology mechanisms such as "if some enzymes molecular structure varies when resistance to high effect cypermethrin results" still need to be researched and perfected thoroughly.