球孢白僵菌对烟草甲幼虫的毒力测定

 为筛选对烟草甲幼虫高毒力的生防真菌,生物测定了球孢白僵菌Beauveria bassiana菌株Bb050722在28℃,25℃,21℃,18℃下对烟草甲Lasioderma serricorne (Fabricius)二龄幼虫的毒力。结果表明,25℃下烟草甲二龄幼虫开始死亡时间较早,其中1.46×10⁸,1.46×10⁷,1.46×10⁶孢子/mL处理后第9d,11d,12d死亡率达到100%。21℃时第4d出现死亡,但是死亡率上升缓慢,只有1.46×10⁸孢子/mL处理在接种后第12d死亡率达100%,在28℃和18℃,烟草甲二龄幼虫分别在第6d和第4d开始死亡。用时间—剂量一死亡率模型处理数据得到:在1.46×10⁸孢子/mL浓度处理下,18℃,21℃,25℃,28℃时球孢白僵菌对烟草甲二龄幼虫的LT₅₀分别为6.3d,3.9d,3.6d,4.1d。结果表明菌株Bb050722对烟草甲防治有一定潜力。

Virulence of Beauveria bassiana against the InstarLarvae of Lasioderma serricorne (Fabricius)

In order to select the fungus which is highly virulent to Lasioderma serricorne (Fabricius), the virulence of the isolate Bb050722 of Beauveria bassiana against the 2nd instar larve of L. serricorne under the condition of 18℃, 21℃, 25℃ and 28℃ was tested in the laboratory. The result showed that the maximum mortality 100% of L. serricorne under the temperature of 25℃was on the 9th d,11th d and 12th d with the inoculation of 1.46×10⁸, 1.46×10⁷ and 1.46×10⁶ spores /mL, respectively. As the temperature was 21℃, the L. serricorne died on the 4th d with a slow increase of mortality, only when treated with 1.46×10⁸ spores /mL, the mortality came up to 100% in the 12th d. At 18℃ and 28℃, the L. serricorne respectively died on the 6th d and 4th d. Data processed with the Time Dose Mortality model (TDM) revealed that the lethal time (LT₅₀) of the B. bassiana against L. serricorne under 18 ℃,21℃,25℃ and 28℃ were 6.3 d, 3.9 d, 3.6 d and 4.1 d, respectively. The fungal strain is contributive to the prevention and control of L. serricorne.