【作者】 蒲玮；

【导师】 侯太平；

【作者基本信息】 四川大学 ， 农药学， 2003， 硕士

【摘要】 通过室内实验、田间观察以及资料调查总结相结合的方法，系统研究了菜青虫的生物学特性，建立了一种快速简便的分龄方法，总结了菜青虫的为害特点和发生规律，提出了菜青虫的防治策略。针对菜青虫防治为目的，对25种有毒植物进行了毒杀和拒食活性的测定。研究发现，瑞香狼毒和巴豆的效果最好。在此基础上，采用不同极性溶剂对瑞香狼毒、巴豆中的活性成分进行了提取分离。结果表明，以乙醇为溶剂可获得较高的提取得率和杀虫活性。分别以不同极性溶剂对乙醇粗提物进行了分极萃取，所得萃取物的生物活性测试结果表明：狼毒和巴豆的正己烷萃取物对菜青虫有较强的毒杀作用和拒食活性。在100倍稀释浓度下，72h内瑞香狼毒正己烷萃取物对菜青虫毒力达91.7％，拒食活性为79.2％；巴豆正己烷萃取液对菜青虫毒力达84.4％，拒食活性为75.0％。72h内两种植物LD₅₀分别为2.26×10³ppm、2.31×10³ppm，AFC_<sup>50分别为2.03×10³ppm、2.42×10³ppm。初步判定这两种植物中毒力较强的活性成分主要是一些非极性或极性较弱的物质。更多还原

【Abstract】 Through experiment and observation as well as collecting and investigating materials, we studied the biological characters of Peris rapae L. A new quick method was built to distinguish the insects of different instar larvas. We summarized its harmfulness and generating rules, came up with a tactics to biocontrol the pest.We tested 25 kinds of poisonous plant species against Peris rapae L. for poison and antifeedant activity. Stellera chamaijasme L. and Croton tiglium L. have been found appearing the best toxicity. On that base, we extracted from the two plants with several different solvents and found the ethanol extract has higher extract rates and toxic activity. Then we made gradient extraction from the anhydrous ethanol extract of the two plants with different solvents. The result showed that the n-hexane extract had significant stronger poison and antifeedant activity against Peris rapae. When diluted the n-hexane extract of the two plants at a concentration of 100 times dilution respectively, the death rates of insects in 72h reached as high as 91.7% and 84.4%, the average antifeedant rates reached as high as 79.2 %and 75.0%. LD50 reached to 2.26× 103ppm, 2.31 ×103ppm. AFC50 reached to 2.03×103ppm, 2.42×103ppm. Finally we drew an elementary conclusion that the fairly strong poisonous components in the two plants were mainly non- polar or weak-polar substance.更多还原