大青叶对小菜蛾杀虫活性部位的初步筛选

以乙醇为溶剂超声提取大青叶中的活性物质,并以石油醚、氯仿、乙酸乙酯、正丁醇、乙醇对提取物依次萃取,采用叶碟法测定提取物对小菜蛾的毒杀活性以研究大青叶对小菜蛾的杀虫活性部位。小菜蛾取食正丁醇提取物浸泡的甘蓝叶片后,24 h即全部死亡,取食石油醚、氯仿提取物浸泡的甘蓝叶片后,96 h全部死亡,取食乙酸乙酯、乙醇提取物浸泡的甘蓝叶片的小菜蛾幼虫在144 h内有不同程度死亡。结果表明:大青叶的各萃取物对小菜蛾均有一定的触杀作用,其中正丁醇和石油醚提取物中均含有较强毒杀小菜蛾的活性物质。

Preliminary Selecting of Insecticidal Activity Parts of Folium Isatidis against Plutella xylostella

In order to study the insecticidal activity parts of folium isatidis against Plutella xylostella,the active substance of folium isatidis was extracted through ultrasonic wave by using ethanol as the menstruum,the extract was leached respectively by petroleum ether,chloroform,ethyl acetate and n-butanol,and its insecticidal activity was determined by leaf disc method.The larvae of Plutella xylostella fed by cabbage leaves soaked in n-butanol extract were totally dead after 24 hours,and they fed by cabbage leaves soaked in petroleum ether extract were completely dead after 48 hours.There were various degrees of deaths for the larvae of Plutella xylostella within 144 hours after they fed on the cabbage leaves soaked in ethyl acetate and ethanol extracts.The results showed that every extract from folium isatidis had a certain contact toxicity against Plutella xylostella,and the n-butanol and petroleum ether extracts had much more active substance against Plutella xylostella.