The Study On Insecticidal Activity Of 24 Plant Against Helicoverpa Armigera And Leucania Separata Walker

The growth and development effects of the powder of twenty-four Chinese plants on the larvae of Helicoverpa armigera were tested by diet-incorporated method in this article and we had a deep test of four high inhibitory rate extracts of the twenty-four Chinese plants,here were the results:1.The growth and development effects of the powder of twenty-four Chinese plants on the larvae of Helicoverpa armigera were tested by diet-incorporated method in this article.The result showed that the powder of Polygonum aviculare,Toona sinensis Roem,Rubia cordifolia L.,Acacia catechu Willd, Paeonia suffruticosa Andr and Pulsatilla chiensis Regel had much effect on the larvae of Helicoverpa armigera.All of that the inhibitory rate were below 75%and the Rubia cordifolia L.was the best one,which inhibitory rate reached 84.47%five days after treatment.At that moment the average weight of the larvae of Helicoverspa armigera were only 43.15mg while the average weight of Helicoverpa armigera larvae of the CK were 285.27mg seven days after changed the Rubia cordifolia L.into normal treatment still kept high inhibitory rate.Also the four treatment larvae duration prolonged several days and had much effect on pupation and eclosion.2.The antifeedant activity of Rubia cordifolia L.extracts against Helicoverpa armigera and Leucania separata Walker were tested.The results showed that the 95%ethanol extract were the best one,the antifeedant rate against Helicoverpa armigera after 24 hour were 90.76%and were 80.14% against Leucania separata Walker.The stomach toxicity of the petrol ether extract against Helicoverpa armigera and Leucania separata Walker were the best one and the adjusted mortality of petrol ether extract against Helicoverpa armigera after 24,48 hour were 20%,30.33%and 18.7%,22.6%against Leucania separata Walker.3.The Acacia catechu Willd,Pulsatilla chiensis Regel and Paeonia suffruticosa Andr 95%ethanol extract had better antifeedant rate against Helicoverpa armigera and Leucania separata Walker.The AFC₅₀against Helicoverpa armigera after 24 hour were 33.22,10.37,16.54 g.L^-1.The AFC₅₀against Leucania separata Walker after 24 hour were 15.41,25.28,3.80g.L^-1.The LC₅₀of Acacia catechu Willd. 95%ethanol extract against Helicoverpa armigera after 24 hour and 48 hour were 55.38,45.49 g.L^-1and the Pulsatilla chiensis Regel were 51.28,45.32g.L^-1and the Paeonia suffruticosa Andr were 136.52, 123.31g.L^-1.However,they had bad stomach toxicity against Leucania separata Walker and the LC₅₀ were all above 96.68 g.L^-1.4.The petrol ether extract and chloroform extract had much effect on the larvae of Helicoverpa armigera.The n-Butanol extract had the best antifeedant activity against Helicoverpa armigera and the best food refusal rate were 99.7%.The ethyl acetate extract had the best antifeedant activity against Leucania separata Walker and the AFC₅₀were 2.50 g.L^-124 hour after treatment.The ethyl acetate extract had better stomach toxicity and The LC₅₀were 5.68,5.30 g.L^-1after 24,48 hour against Helicoverpa armigera and 4.80,4.60g.L^-124,48 hour after treatment against Leucania separata Walker.5.Every component of the ethyl acetate extract by TLC had a certain effect on the growth and development of the Helicoverpa armigera.The component 4,6-7 and 9 had much effect on the Helicoverpa armigera and the component 4 were the best one.