Effects Of Abrus Precatorius Seed Extract On Biological Activities And Enzymes Of Brevicoryne Brassicae And Plutella Xylostella

In this paper,the biological activities of Abrus precatorius seed extracts against Brevicoryne brassicae and Plutella xylostella were studied,and the optimum extracted solvents for different biological activities of B.brassicae and P.xylostella were determined.The biochemical mechanism of petroleum ether extract of A.precatorius seed on contact toxicity B.brassicae and P.xylostella was discussed.It provided a theoretical basis for the development and utilization of botanical pesticides and the green control of B.brassicae and P.xylostella.The main results are as follows:1.43 species of insecticidal plants were screened preliminarily.The contact toxicity and deterrent effect of ethanol extracts from 43 insecticidal plants on P.xylostella and B.brassicae were studied.The results showed that 18 plants had contact toxicity effect of more than 50%and 15 plants had deterrent effect of 50%.Among the 43 plants,A.precatorius had the best contact toxicity on P.xylostella and B.brassicae,which were 80%and 85%.2.Bioactivity of A.precatorius seed extracts from different solvents against P.xylostellaand B.brassicae.The results showed that:(1)The extraction rates of Acacia seeds by five organic reagents,methanol,acetone,ethanol,ethyl acetate and petroleun ether,were]3.25%,8.15%,7.64%,2.54%and 2.13%.(2)Petroleum ether extract of A.precatorius seed had the highest contact activity to B.brassicae and P.xylostella,and LCso was 2.18 mg/mL and 7.22 mg/mL respectively after 72 hours of treatment.(3)In the study of the antifeedant effect of P.xylostella,the average antifeedant rate of ethyl acetate extract was the highest among the five extracts at 100 mg/mL concentration(39.95%).The average antifeedant rate of ethanol extracts was the lowest(25.62%).(4)In the study of stomach action,the average Corrected morality of ethyl acetate extract of A.precatorius among the five extracts at 100 mg/mL concentration was the highest(50.00%),and the average corrected morality of methanol extract was the lowest(29.17%).(5)Explored the selective oviposition deterrent effect of P.xylostella adults.The average oviposition deterrent rate of A.precatorius seed ethyl acetate extract among the five extracts at 100 mg/mL was the highest(53.99%),and average oviposition deterrent rate of methanol extract was the lowest(40.80%).(6)In the study on the deterrent effect of B.brassicae,the deterrent effect rate of A.precatorius seed ethyl acetate extract among the five extracts at 100 mg/mL was the highest(97.72%),and acetone extracts was the lowest(75.67%).3.The effect of petroleum ether extract ofA.precatorius seed on the activity of enzymes in P.xylostella and B.brassicae.The sublethal dose gradient of petroleum ether extract of A.precatorius seed against B.brassicae and P.xylostella and the time gradient of LC50 concentration of B.brassicae and P.xylostella were set up in this experiment.The results show that:(1)AChE activity decreases with the increase of sublethal dose of P.xylostella and B.brassicae,and the highest inhibition rate of AChE activity was 34.09%at LC50 concentration after 12 hours.The highest inhibition rate of AChE activity of B.brassicae was 56.43%after 24 hours.(2)The GST activity of R xylostellaand B.brassicae reached the highest at LC20 sublethal dose,and then the inhibition rate increased with the increase of LC50 concentration.The inhibition rate of GST activity in P.xylostella at LC50 concentration was 47.69%after 48 h,and the inhibition rate of GST activity in B.brassicae after 36 h was 66.20%.(3)The activity of CarE in P.xylostella was inhibited at sublethal dose,while the activity of CarE in B.brassicae showed a gentle upward trend.The activity of CarE in P.xylostella and B.brassicae at LC50 concentration was lo1ver than that in control group at 60 h.