Toxicity And Mechanisms Of Bombys Batrticatus Ethanol Extract Against Helicoverpa Armigera

The cotton bollworm Helicoverpa armigera is one of worldwide important pest toagriculture. There are many studies to seek pest control measures for cotton bollworm everyyear. But each control measure breeds new problems and challenges. So it’s important for usto continue to looking for new routes. As a tradition Chinese medicine, Bombyx batrycatuswas found on its insecticidal activity by previous study. Study on toxicity and mechanism ofaction of Bombyx batrycatus ethanol extract (BBE) against Helicoverpa armigera, providenew material to animal origin pesticide. In this study, stomach poisoning action andantifeedant activity of Bombys Batrticatus ethanol extract were examined. we also tested theenzymatic activity of ALP, ACP, CarE and the expression level of ALP. In addition,cytotoxicity of Bombys Batrticatus ethanol extract to HZAM1was also studied. Followingwere the results:Bombyx batrycatus ethanol extract has strong stomach toxicity and antifeedant activity toH. armigera.4days of LC50is1.47mg/g and LC90is23.97mg/g to1th instar lavae.5days ofLC50is1.32mg/g and LC90is24.31mg/g to2th instar lavae.7days of LC50is1.22mg/g andLC90is16.63mg/g to3th instar lavae.9days of LC50is0.66mg/g and LC90is6.83mg/g to4thinstar lavae. On the other hand, compare with the control group,3th instar lavae feeded withBB extract have lower daily diet consumption and total accumulation of diet consumption. Inaddition, BB extract has no contact toxicity to3th instar lavae.The activity of ALP was inhibited by BBE. And this inhibition effect has concentrationscorrelativity and temporal dependent. The activity of ACP in the tested larvae was activated inthe6h and12h, following with be inhibited in24h,48h and72h. The activity of carboxylesterases (CarE) in the tested larvae was activated when the concentration of treatment wasrelatively high.The gene expression level of ALP in the midgut of3th instar lavae feeded with BBE wasdetermined. The results of RT-PCR and Western blot shown that the expression level of ALPwas significantly down regulated after treated with BBE.Cytotoxicity test shown that the morphology of HZAM1cell changed began to shrink,bubble cavitation, edge fog, even dead48h after treatment with BBE and the viability ofHZAM1cell were inhibited. The inhibition effect correlated with concentration and time. Genomic DNA was digested into fragment18h after treated with Bombys Batrticatus ethanolextract. And the degree of degradation of the genomic DNA has a concentration correlation.