假臭草对菜青虫杀虫活性的研究

测定了假臭草根、茎、叶的甲醇提取液对菜青虫的生物活性。结果表明假臭草根、茎、叶的甲醇提取液对菜青虫无触杀活性;假臭草提取液对菜青虫的拒食活性强弱依次为叶茎根,在浓度为1 g/mL时拒食率分别为36.51%、63.34%和79.33%;假臭草茎和叶的甲醇提取液对菜青虫有一定的胃毒作用,在浓度为1 g/mL时,假臭草叶和茎甲醇提取液对菜青虫的胃毒活性分别为66.67%和33.33%。

Insecticidal Activity of Plant Extracts from Praxelis clematidea against Pieris rapae

Bioactivity of methanol extracts of Praxelis clematidea against mixed instar of Pieris rapae were reported. Results showed that extracts of roots, stem and leaves of Praxelis clematidea had no contacting effect on Pieris rapae. Among these methanol extracts from Praxelis clematidea, the extract of leaves of Praxelis clematidea antifeedant activity the strongest activity, and the extract of roots of Praxelis clemati- dea antifeedant activity the lowest activity. The antifeedant activity of Pieris rapae were 36. 51%, 63.34% and 79.33% respectively when the concentration were 1 g/mL. The extract of leaves and stem of Praxelis clematidea had stomach action on the Pieris rapae. At the concentration of 1 g/mL, the cor- rected mortality of the Pieris rapae was 66.67% and 33.33%.