筋骨草内昆虫蜕皮激素类似物对杨干象的杀虫作用

摘要

Eight kinds of phytoecdysteroids extracted from different parts of Ajuga multiflora Bunge (Labiatae) that were collected from different places at different time were tested for killing effects on the 2-instar larvae of Cryptorrhynchus lapathi L by adding them to the artificial diet of larvae. The experimental results indicated that adding 1-3-mL phytoecdysteroids to the artificial diet could lead 58%-100% of 2-instar larvae of C. lapathi to death within 24 days. The phytoecdysteroids extracted from the whole plant of A. multiflora which was collected before flowering time were much more effective than those extracted from the plants collected at flowering and after flowering periods, and the modified mortality rate of larvae reached 65.22%, 85.07%, and 98.11% at the dosage level of 1-mL, 2-mL, and 3-mL extracts, respectively. The extract made from root of A. multiflora plant was more effective in killing efficiency than those from stem and leaves, and the average death rates of larvae were up to 100%, 98.20% and 98.32% at dosage levels of 1-mL, 2-mL, and 3-mL extracts, respectively. The killing speed of the extracted phytoecdysteroids was slower than that of triflumuron, hexaflumuron or deltamethrin emulsifiable concentrate. The mortality rate of larvae is closely related to the feeding duration on the diets containing phytoecdysteroids. Feeding on the diets with addition of phytoecdysteroids for 16 days, more than 80% of treated 2-instar larvae of C. lapathi were led to death. The killing effect of the extracts was little affected by the growth areas of A. multiflora plant and the adding way to artificial diet.%从不同地点、不同时间采集的多花筋骨草植株不同部位中提取出昆虫蜕皮激素类似物，通过向幼虫人工饲料中添加昆虫蜕皮激素类似物的方法，研究了筋骨草中植物源蜕皮激素对杨干象2龄幼虫的杀虫作用。实验结果表明：（1）在人工饲料中加入1-3 ml的筋骨草提取物，在24天内可以杀死 58%~100%的幼虫；（2）从开花前的筋骨草中提取出的物质的杀虫效果明显优于从花期和开花后的植物中提取出的物质的杀虫作用, 其1 mL、2 mL和3 mL剂量全株提取物的杀虫效果分别达到65.22%、85.07%和98.11%（幼虫校正死亡率）;（3）植株的根部提取的昆虫蜕皮激素类似物的杀虫效果要比茎部或叶部提取的好，1 mL、2 mL、3 mL剂量提取物的杀虫效果分别达到100%、98.20%和98.32%；（4）筋骨草提取物的杀虫速度较慢，处理杨干象2龄幼虫16天后杀虫率才超过50%；（5）幼虫取食加有筋骨草提取物的饲料时间长短直接影响幼虫死亡率，16天的取食，幼虫死亡率达到80%以上。筋骨草采集地点和填加植物源蜕皮激素的方式对杀虫效果的影响较小。