灰毛豆甲醇提取物的杀虫活性

研究灰毛豆(Tephrosia purpurea)各部位提取物的杀虫活性及其作用方式。结果表明,灰毛豆对白纹伊蚊Aedes albopictus Skuse幼虫、菜青虫Pieris rapae(L.)、斜纹夜蛾Prodenialitura(Fabricius)幼虫和黄曲条跳甲Phyllotreta striolata(Fabricius)成虫都有杀虫活性。灰毛豆种子、树皮、根皮、豆荚、枝条和树叶的甲醇提取物对白纹伊蚊4龄幼虫24h的LC50值分别是22.1,97.7,36.6,142.6,165.6和618.3mg.L-1,树干木质部没有杀虫活性;灰毛豆种子、树皮和根皮甲醇提取物对3龄菜青虫24h的触杀毒力LC50值分别是232.1,206.3和236.7mg.L-1;种子、树皮、根皮、枝条、树叶和豆荚对3龄菜青虫的24h胃毒毒力LC50值分别是192.6,168.4,249.7,524.5,1001.0,和510.7mg.L-1。在取食或接触有提取物的叶碟后,5龄菜青虫会出现取食量减少和生长发育变慢的亚致死现象。这些研究结果表明,灰毛豆除茎干木质部以外的其它各部位均含有杀虫活性成分,其作用方式为胃毒和触杀。

Insecticidal activity of methanol extracts from Tephrosia purpurea

Insecticidal activity of methanol extracts from every part of Tephrosia purpurea was reported for the first time. The result showed that T.purpurea possessed insecticidal activity against the 4th instar larvae of Aedes albopictus Skuse, the 3rd instar larvae of Prodenia litura, the 3rd instar larvae of Pieris rapae (L.), and adult of Phyllotreta striolata (Fabricius). The LC_ 50 value of methanol extracts from the seeds, the stem bark, the root bark, the bean-pod, the branch, and the leaf against the 4th instar larvae of A. albopictus were 22.1, 97.7, 36.6, 142.6, 165.6, and 618.3 mg·L -1 at 24 h after treatment,respectively. The xylem of trunk did not present insecticidal activity. The methanol extracts from the seeds,the stem bark, and the root bark possessed contact toxicity against the 3rd instar larvae of P. rapae,with corresponding LC_ 50 value of 232.1,206.3,and 236.7 mg·L -1 at 24 h after treatment. The methanol extracts from the seeds, the stem bark, the root bark, the branch, the leaf, and the bean-pod exhibited stomach toxicity against the 3rd instar larvae of P. rapae,with respective LC_ 50 values being 192.6, 168.4, 249.7, 524.5, 1 001.0, and 510.7 mg·L -1 at 24 h after treatment. Reduction of food consumption and growth inhibition for the 5th instar larvae of P. rapae were sublethal effect after the insect pest contact or eat leaf disc with extracts from active part. The findings suggested as follows: every part of T. purpurea except xylem of trunk exhibited insecticidal activity. The action mode were stomach action and contact action.