Extracts and Bioassays of Active Substance of Ajuga Nipponensis against Pieris Rapae L.

Ethanol,n-butanol,ethyl acetate and chloroform are used to obtain the active ingredients from the overground part plant of Ajuga nipponensis,and the bioactivity of the extracts against the 3th instar larvae of Pieris rapae L.is investigated.The results show that the extracts of Ajuga nipponensis have insecticidal effect on Pieris rapae L.,anti-feeding rate and correction mortality in chloroform and ethyl acetate extract are significantly higher than that in other group,The rates of deterring the continuation of feeding of chloroform extract and ethyl acetate extract reached 92.00% and 90.00% respectively;the 24h and 48h correction mortality in chloroform extract reaches 21.23% and 32.69% respectively;and that in ethyl acetate extract reaches 20.67% and 31.24% respectively.Conclusion: the extracts of four organic solvent from Ajuga nipponensis have antifeedant effect and contacting toxcity on Pieris rapae L.the insecticidal effect of chloroform and ethyl acetate extract are most significant.