天祝天然草地3种有毒植物提取物对粘虫的生物活性

测定了3种有毒植物露蕊乌头，铁棒槌和马先蒿的4种溶剂的提取物对粘虫的杀虫活性。结果表明：露蕊乌头甲醇、乙醇提取物对粘虫均具有一定的触杀活性，LC50分别为3．63、5．79g／L；露蕊乌头甲醇提取物，马先蒿丙酮提取物和铁棒槌甲醇提取物对粘虫的胃毒活性表现较强，杀虫活性LC50分别为2．13，2．82和3．22g／L，马先蒿和铁棒槌的石油醚提取物对粘虫无胃毒活性。3种植物的4种溶剂的提取物对粘虫均表现出一定的拒食活性，其中甲醇提取物的拒食活性都较高，露蕊乌头甲醇提取物对粘虫的拒食活性明显高于其他提取物，当质量浓度达到0．2g／mL时，拒食率为97．6％。而3种植物石油醚提取物的拒食活性均较差。

Insecticidal activity of three poisonous plant extracts against Mythimna separata

Laboratory studies were conducted to determine and compare the insecticidal activities of extracts from 3 poisonous plants in Tian Zhu alpine grassland.The results show that only the carbinol and ethanol extracts of Aconitum gymnandrum have determinate contact toxicity agaist armyworm with the LC50 values at 3.63,2.82 and 5.79 g/L.The carbinol extracts of A.gymnandrum,A.szechnyianum and Pedicularis scrophylariaceae exhibited strong insecticidal activity,their armyworm insecticidal LC50 values were 2.13,2.82 and 3.22 g/L respectively.The petroleum ether extracts of the three plant specises had weak insecticidal activity,such as petroleum ether extracts of A.szechnyianum and P.scrophylariaceae showed no significant stomach toxicity against armyworm.The extracts of the three different plant species which distilled from the 4 solvents exhibited difinite antifeedant activity to armyworm as well.The antifeedant activity of carbinol extracts from A.gymnandrum were obviously stronger than the others,and when the root extract of A.gymnandrum at 0.2 g/mL provided 97.6% inhibition of antifeedant rate in armyworm.The results also show that the antifeedant activities of petroleum ether extracts from the three poisonous plants were relatively weak.