几种虫生真菌对烟青虫的致病性研究

Studies on Pathogenicity of Several Fungal Species on Helicoverpa assulta

用 4种真菌共 9个菌株的固体培养物以及真菌与 Bt的混合物 ,分别对烟青虫 2龄幼虫进行了毒力测定 ,结果表明 :( 1 )球孢白僵菌和莱氏野村菌两个菌种对烟青虫幼虫有明显的防治效果 ,且前者优于后者 ;在白僵菌中 5 S0 3菌株毒力最高 ,对烟青虫 2龄幼虫的致死中时 ( LT50 )为 6.1 0 d,校正死亡率为 86.96% ,僵虫率为 33.33% ;另外两个菌株 Bb3和 Bb98-1的毒力也较高。 ( 2 )真菌 ( 5 S0 3)与 Bt混用 ,对防治烟青虫具有相互增效作用。

In this paper,virulence of the solid products of the four fungal species (total 9 strains) as well as the mixture of the fungi and Bt (Bacillus thuringiensis) formulation to H.assulta larvae were tested. The results showed as follows: (1) Virulence of different fungal species and strains was various.Beauveria bassiana and Nomuraea rileyi had obvious controlling efficacy to H.assulta,and the former was prior to the latter. Virulence of the B.b strain 5S03 to H.assulta was highest, the LT 50 for the 2nd instar larvae of H.assulta was about 6 10 days, adjusted death rate was 86 96 percent,and muscardine cadaver rate was 33 33 percent.(2) The controlling efficacy to H.assulta was enhanced when the strain 5S03 was mixed with Bt.