杀葱蝇高毒力真菌菌株的筛选

Screening of Higher Virulent Fungal Strain against Delia antigua

从实验室保存的真菌菌株初步筛选获得6株对葱蝇有一定致病力的白僵菌菌株,通过室内生测进一步测定不同菌株对葱蝇幼虫的毒力。测试结果表明,在相同浓度的孢子悬浮液处理下(1×107孢子/m L),菌株CQBb119的致死率最强,第14 d对葱蝇幼虫的致死率达到77.78%,僵虫率达到58.52%,致死中时(LT50)为6.10 d。使用不同浓度孢子悬浮液处理葱蝇的各个虫态,结果显示,在不同浓度孢子悬浮液处理下,随着孢子悬浮液浓度的增加,葱蝇的死亡率逐渐升高,致死中时降低。在1×108和1×109孢子/m L浓度的菌液处理下,第14 d对葱蝇幼虫的LT50分别为5.48和4.94 d;LC50为1.35×106孢子/m L。菌株CQBb119对葱蝇成虫和蛹也有一定致死作用,但成虫和蛹的死亡率均未能达到50%。结果表明,球孢白僵菌菌株CQBb119对葱蝇幼虫具有良好杀虫活性,可以用于防控葱蝇的潜在生防制剂开发。

Six strains of entomopathogenic Beauveria bassiana were screened depending on virulence against Delia antigua. The virulence of these strains against D. antigua were further evaluated in laboratory. Bioassay results showed that the strain CQBb119 had the highest virulence. The accumulative mortality reached 77.78% and the cadaver rate reached 58.52%. The LT50 value was 6.10 d when D. antigua maggot were treated with 1×107 spores/m L spore suspension for 14 d. Inoculated on maggot, pupa, and onion fly of the D. antigua, the test results indicated that the mortality of D. antigua increased with the concentration of the spores suspension while the median lethal time fell. When treated with 1×108 and 1×109 spores/m L spores suspension of CQBb119, LT50 values of D. antigua maggot were 5.48 d and 4.94 d. The LC50 value at 14 th day was 1.35×106 spores/m L. B. bassiana CQBb119 had a certain virulence against the onion fly and pupa but the mortality was lower than 50%. The results indicated that the screened entomopathogenic B. bassiana CQBb119 had effective insecticidal activity, and could be used as a potential biological pesticide for controlling of D. antigua.