采用9种极性不同的溶剂利用冷浸法从马齿苋(Portulaca oleracea L.)干粉中制备提取物,测定了其对棉蚜(Aphis gossypii Glover)的毒杀和拒食活性。浸渍法实验结果表明,处理24h后,马齿苋甲醇提取物对棉蚜的毒杀活性最高,LC₅₀为6.63mg·mL^-1(以干粉计,下同);二氯甲烷提取物在质量浓度为100mg·mL^-1时对棉蚜的拒食率最高,达83.03%。处理48h后,丙酮提取物对棉蚜的毒杀活性最高,LC₅₀为1.88mg·mL^-1;二氯甲烷提取物在质量浓度为100mg·mL^-1时拒食率仍表现为最高,达83.97%。在质量浓度为25mg·mL-1时,以石油醚提取物的拒食率最高,处理24和48h对棉蚜的拒食率分别达到71.25%和81.20%。

ried powder of Portulaca oleracea L. were extracted by the dipping method with methanol, ethanol, acetone, ethyl acetate, ether, trichloromethane, dichloromethane, benzene and petroleum ether, and bioactivity of the extracts against Aphis gossypii Glover including contact toxicity and antifeeding toxicity were approached. The results indicated that the methanol extract showed the highest contact toxicity with 6.63 mg·mL^-1(dried powder) of LC₅₀among the 9 different extracts and the dichloromethane extract had the highest antifeeding toxicity with antifeeding rate 83.03% at the quality concentration 100mg·mL^-1(dried powder) in the extracts after 24 h. After 48 h, the contact toxicity of the acetone extract was the highest with LC₅₀1.88 mg·mL^-1 and the dichloromethane extract had the highest antifeeding toxicity with antifeeding rate 83.97% at the quality concentration 100 mg·mL^-1.Under the concentration of 25 mg·mL^-1, the antifeeding rate of the petroleum ether extract was the highest, reached to 71. 25% and 81. 20% after 24 and 48 h respectively. The sequence of bioassay results for both contact toxicity and antifeeding toxicity of the 9 extracts from P. oleracea were also arranged respectively.