六株牛蒡共生真菌的杀虫活性

为了进一步开发和利用滨海植物牛蒡（Arctium lappa）的生物资源,寻找新型微生物农药,对来自牛蒡的6株共生真菌NY-2,NY-3,NY-4,NY-5,NY-6和NG-1的菌丝体和发酵液分别进行了对卤虫（Brine shrimp）杀虫活性的研究.结果表明：杀虫实验24h后,6株共生真菌的菌丝体和发酵液的乙酸乙酯提取物均表现出不同强度的杀虫活性,随着加样浓度的增加,卤虫死亡率也随之提高.6株共生真菌的菌丝体/发酵液对卤虫的半数致死浓度（LD50单位：mg·mL-1）分别是0.476 2/0.116 8,0.477 9/0.068 7,0.685 1/0.254 4,0.090 8/0.028 5,0.312 7/0.190 5,0.662 3/0.085 8;经与3种常见化学农药氯氰菊酯、敌敌畏和氧乐果的杀虫活性对比,6株真菌的杀虫活性全部优于以上3种农药,特别是NY-5发酵液的LD50仅为0.028 5mg· mL-1,其杀虫活性是农药对照组活性最好的敌敌畏的21倍.牛蒡的共生真菌是一个良好的微生物农药的生物来源.

Insecticidal Activities of Six Symbiotic Fungi from Arctium Lappa

Six symbiotic fungi which were isolated from Arctium lappa were studied in terms of insecticidal activity to Brine shrimp with the intent of developing a new microbial pesticide.The fungi are namely as NY-2,NY-3,NY-4,NY-5,NY-6 and NG-1.And the results showed that the extracts,both from the mycelium and the fermentation broth,are of relatively higher insecticidal activity when compared with three kinds of chemical pesticides.The more extracts added into the tube the higher insecticidal activity it showed.The median lethal dose LD50 of each fungus （mycelium/fermentation broth） are 0.476 2/0.116 8,0.477 9/0.068 7,0.685 1/0.254 4,0.090 8/0.028 5,0.312 7/0.190 5,0.662 3/0.085 8 （mg · mL-1） respectively.Moreover,the insecticidal activity of the extract from NY 5 fermentation broth is 21 times of dichlorvos.Arctium lappa may be a promising resource for new microbial pesticides.