胡芦巴不同溶剂粗提物对两种储粮害虫的驱避和触杀活性

Repellency and Contact Toxicity of Extracts by Different Solvents from Trigonella foenum-graecum L. against Two Pest Species

为开发环境和谐的植物性杀虫剂,以乙醇、乙酸乙酯、丙酮、氯仿、石油醚为溶剂采用温浸回流法对胡芦巴Trigonella foenum-graecumL.种子中的生物活性物质进行提取;并以主要储粮害虫杂拟谷盗Triboli-um confusumdu Val、谷蠹Rhyzopertha dominicaFbricius成虫为试验对象,采用滤纸药膜法对胡芦巴5种溶剂粗提物进行驱避、触杀活性测定。结果表明:5种溶剂粗提物对杂拟谷盗的驱避作用均优于对谷蠹的作用:在各粗提物剂量为1.6μg/cm2时,对杂拟谷盗处理7 d后的平均驱避率均超过80%,驱避等级为Ⅴ级,其中丙酮粗提物效果最好。但5种溶剂粗提物对谷蠹的触杀作用却均优于对杂拟谷盗的作用:处理72 h后,乙醇、乙酸乙酯、丙酮、氯仿粗提物对谷蠹成虫的LD50依次为0.112、0.102、0.106、0.100 mg/cm2,石油醚粗提物的触杀活性相对较差;乙醇、乙酸乙酯、氯仿粗提物用0.91 mg/cm2剂量处理72 h后,杂拟谷盗成虫的平均死亡率分别为95.56%、72.22%、87.78%;丙酮、石油醚粗提物用1.04 mg/cm2剂量处理72 h后,杂拟谷盗成虫的平均死亡率分别为57.78%和53.33%。

In order to develop environment friendly botanical pesticides, powdered seeds of Trigonella foentm- graecum L. were extracted with alcohol, ethyl acetate, acetone, chloroform, and petroleum ether at relatively high temperature by dipping the extract flask in warm water. The repellency and contact activities of the extracts by different solvents from Trigonella foenum-graecum L. seeds against adults of Tribolium confusum du Val and Rhyzopertha dominica Fabricius were examined using the filter- paper drug - film method under the laboratory conditions. Results show that all the five extracts exhibit higher repellency against T. eonfusum than against R. dominica. The average repellency against adults of T. confusum exceeds 80% on 7th d after treatment with an extract concentration of 1.6 μg/cm^2 for all the five extracts, the repellency level deserves degree V, and the acetone extract performs the best. However, all the extracts exhibit higher contact toxicity against R. dominica than against T. confusum. After the treatment of 72 h, the LD50 of the extracts by alcohol, ethyl acetate, acetone and chloroform against adults of R. dominica are 0. 112, 0. 102, 0. 106, 0. 100 mg/cm^2, respectively, and the petroleum ether extract exhibits relatively weak. As for the contact toxicity against adults of T. confusum, with an extract concentration of 0.91 mg/cm^2, the average mortality at 72 th h after the treatments of alcohol, ethyl acetate and chloroform extracts is 95.56%, 72.22%, 87.78%, respectively; with an extract concentration of 1.04 mg/ cm^2, the average mortality against adults of T. confusum at 72th h after the treatments of acetone and petroleum ether extracts is 57.78 % and 53.33 %, respectively.