Study On Resistance Mechanisms Of Tetranychus Urticae Koch To Fenpropathrin

Two-spotted spidedr mite(Tetranychus urticae Koch) is one of the most pest mite population on fruit trees,vegetables and crops,the kind of pyrethroid acaricide was used to prevent mite like fenpropathrin for a long time. The pyrethroid acaricide became the critical acaricide in China since has these characters, such as,high virulence to mite,compatibility is good with environment,low-toxic to human and animal,non-residue contamination and safety to natural enemy.But it also brought the mite resistance to acaricide,for example the Tetranychus urticae Koch,for the great quantity,unitary and continuous various used.The thesis had clearly definited the horizon of resistance by field monitored the Tetranychus urticae Koch in He Xi area of GanSu province,which can be used to guiding peasant for production;fifteen kinds of acaricide were tested out the cross-resistance admeasurement on FeR Tetranychus urticae Koch, thought proliferated the population by amphoterotoky and cultivated the FeR strain in laboratory.These have provided the reliable theory about the acaricide to take turns reasonably and use thoughtlessly;The analysis to the biochemistry and physiology of the FeR strain, made clear the relation of the in vivo detoxifieation enzyme changes of FeR to resistance to acaricide,providing the basis references of technology about monitoring for resistance of the Tetranychus urticae Koch to fenpropathrin.The results obtained are summarized as follows:1.Testing the selection and cross-resistance about Tetranychus urticae Koch to Fenpropathrin.Thought proliferated the population by amphoterotoky and cultivated the S strain of Tetranychus urticae Koch in laboratory,which was collected from XingLongShan of GanSu Province.The resistance rise to fenpropathrin was detached for five stages: F₃^F₅,F₅^F₁₁,F₁₁^F₁₂,F₁₂^F₁₄ and F₁₄^F₁₉, The resistance rised quickly by resistance selection in laboratory;Resistance index up to 88.37-fold on F₁₉, and would be rising.The result showed that resistance of Tetranychus urticae Koch to cyhalothrin reached to 12.21-fold,Celastrus angulatus was 10.82-fold,these had obviously cross-resistance;But the omethoate,fenbutatin oxide,fenpyroximate,cypermethrin and azocyclotin only amounted to 6.35-fold,7.54-fold,6.878-fold,9.79-fold and 6.65-fold,which had not very obvious for cross-resistance.2.The biochemistry mechanism of resistance about Tetranychus urticae Koch to FenpropathrinThe analysis of variance about the carboxylesterases activity was extremely notable between resistance strain and sensitive strain of Tetranychus urticae Koch,such as,the FeR enzyme vigour is 1.0969-fold of S enzyme vigour;Under identical reaction condition,the OD value increased as well as the enzyme concentration increased,the OD value was 0.27 as the enzyme concentration was 2.5pr/mL of FeR,but S strain OD value was 0.245,the FeR was the 1.102-fold than the S,indicated that the activity of CarE in any stage relevant to the resistance strengthen. The activity of the phosphoric acid and the Alkaline phosphatase about FeR were 0.1410μM/mg.pr/30min and 0.1181μM/mg.pr/30min,while the S strain of the two enzymes were lower than FeR strain as 0.1328μM/mg.pr/30min and 0.0072μM/mg.pr/30min,The analysis of variance of phosphatase showed notable difference between the FeR and S strain.Those testified that the Tetranychus urticae Koch became resistance to fenpropathrin was relevant to the activity increase of the phosphatase,and the increase was one of the reasons for Tetranychus urticae Koch became resistance.The trend about activity of Glutathione S-transferase enzyme of S strain reduced,through determined the changes of OD value within 3 mins,the activity of FeR higher than S in addition to the first 40s,which explained that the activity increase of GSTs enzyme caused to the resistance,and the resistance increased gradually with time extension.Mixed function oxidase was one of the importance detoxifieation enzymes,the activity of FeR(0.1628mmol·L^-1·mg^-1Pro·(30min)^-1)was the 2.9471-fold than the S(0.0550 mmol·L^-1·mg^-1Pro·(30 min)^-1),the resistance-flod of the MFOs was the highest in three detoxifieation enzymes and showed that had the extremely notable difference,when all is said,MFOs could be the key enzyme for Tetranychus urticae Koch became resistance.3.Monitored the resistance about the Tetranychus urticae Koch of corn to seven insecticide in 3 areas of He Xi.Monitored the resistance level to seven kinds of acaricide on the Tetranychus urticae Koch of corn populations in order to tested the situation about the field resistance of Tetranychus urticae Koch of corn to common acaricides through the mothod of bioassay in Wu Wei,ZhangYe and Jiu Quan territory of GanSu Province,the results can be used to guiding peasant for production. indicated that difference population has difference resistance level on the seven kinds of acaricide, The resistance of mite to Fenpropathrin belonged to medium and not obviously in the 3 areas;The resistance to beta-cyfluthrin like this:Wu Wei population> Zhang Ye population> Jiu Quan population;compared with the others, the resistance leval to avermectin, dicofol and pyridaben were low respectively in the 3 areas.