Resistance Examination Of Helicoverpa Assulta And Primary Studies On Resistance Mechanism In China

The purpose of this paper is to examine the resistance of Helicoverpa assultain main planting tobacco areas of our country.Besides, the resistance mechanism isalso studied. The resistance of Helicoverpa assulta that came from six differenttobacco regions in Shandong,Hubei and Henan province to four kinds ofinsecticides that was fenvalerate , phoxim , methomyl and chlorfenapyr wasmeasured by topical application method.And the resistance strain wasestablished.The resistance mechanism was studied by means of synergist andenzyme dynamics.At the same time ,many kinds of insectsides were filtered bytopical application method. The main results were as follows:1. The resistance of Helicoverpa assulta that came from six different tobaccoregions in Shandong,Hubei and Henan province to four kinds of insecticide wasmeasured by topical application method.Results showed that the resistance ofXuchang population in Henan province to fenvalerate was the highest and theZigui population in Hubei took second place and the Changyang Hubei populationwas the lowest, which reached 64.89 fold and 28.49 fold and 5.53 foldrespectively.And the resistance of other populations were little higher than that ofChangyang population. Six Helicoverpa assulta populations bringed variousdegrees of resistances to phoxim and methomyl. And there were a little differenceon toxicity to chlorfenapyr ,but their value of LD50 were higher comparativelywhich shows this kind of pesticide was not sensitive to Helicoverpa assulta.2.Synergism of four kinds of pesticides by five synergist were measured,theresults showed that:The resistance to fenvalerate was related to the improving ofthe activity of detoxifcation enzyme and that of GST. The resistance to phoximand methomyl was related to the improving of the activity of isozyme and thereducing of the cuticle penetration. The resistance to chlorfenapyr was related tothe improving of the activity of GST. 3.The activity of Care,ACHE and GST of the fourth instar larva of helicoverpaassult were measured ,the result showed that:the quantity and the activity of Careof fenvalerate-resistance population were higher than the sensitive population,and italso showed that it not only differed from the quantity but from the qulity. thequantity and the activity of Care of other three resistance population didn't havedifference evidently from the sensitive population.The activity of ACHE ofresistance population didn't have difference evidently from the sensitivepopulation,which showed that the passivation of ACHE wasn't the main reason toproduce resistance.The activity of GST had difference between the resistancepopulation and the sensitive population,which showed that the detoxifcation of GSTwas related to the production of the resistance. 4.The cuticle penetration of the resistance population within 1 hour was higherthan that of the sensitive population to fenvalerate,and it showed a decreading trendwith the increasing of the time.And the results above showed that the decresing ofthe cuticle penetration was related to the resistance to fenvalerate.5.Screening for seven kinds of drugs showed that the virulence of beta-cyfluthrinand Indoxacarb was the highest,and chlorpyrifos, profenofos and endosulfan alsowere perfect pesdticide to manage the orient tobacco budworm. Chlorfluazuron,a chitin synthesis inhibitors, and spinosad ,a insecticidal antibiotic,have perfect...