Study on Contact and Antifeedant Activity of Portulaca oleracea Extracts against Plutella xylostella

[Objective] The aim was to provide the clue and the theoretical basis for developing the new botanical insecticide with the Portulaca oleracea as material.[Method] The extracts were prepared using 9 kinds of solvents with different polarity from P.oleracea dry powder by cold dip method and the contact and antifeedant activity of the extracts against P.xylostella were detected.[Result] P.xylostella dry powder extracts at 100 mg/ml had higher contact and antifeedant activity against P.xylostella.The contact activity of methanol extract from P.xylostella against P.xylostella treated for 24 h was highest and that of acetone extract was highest after the moth was treated for 48 h.The contact activity of each extract was increased after P.xylostella was treated for 48 h compared with that treated for 24 h.When each extract was 25 mg/ml,the antifeedant activity of petroleum ether extract was highest and the antifeedant activity of each extract was decreased compared with that when each extract was 100 mg/ml.[Conclusion] The solvent extracts with big polarity from P.xylostella dry powder had better toxic action against P.xylostella and the solvent extracts with small polarity had higher antifeedant activity against P.xylostella.