烟草甲幼虫高毒力病原真菌的筛选

为筛选出对烟草甲2龄幼虫具有较好防治效果的病原真菌，在实验室条件下，采用浸渍法测定5株蜡蚧轮枝菌和5株球孢白僵菌对烟草甲2龄幼虫的毒力，筛选出2株对烟草甲2龄幼虫具有高毒力的白僵菌菌株Bb05和Bbr81，将2株菌株配置成不同浓度的孢子悬浮液，测定其毒力并对Bb05菌株的侵染过程进行观察。结果表明，接种孢子浓度1.0×10⁸mL^-1条件下，菌株Bb05处理烟草甲的累积死亡率最高，达77.78%，LT₅₀为8.18 d；菌株Bbr81处理烟草甲的累积死亡率为74.44%，LT₅₀为7.60 d。用不同浓度孢子悬浮液处理烟草甲2龄幼虫后，其累积死亡率随孢子浓度和接种时间的增加而增加，Bb05菌株的LC₅₀为8.3×10⁷ mL^-1，菌株Bbr81的LC₅₀为1.2×10⁷ mL^-1。筛选所得的2个菌株对烟草甲虫2龄幼虫的毒力较高，具有一定的开发应用潜力。

Screening for Highly Virulent Entomopathogenic Fungi Against Lasioderma serricorne (Fabricius) Larvae

In order to screen for entomopathogenic fungi with better control effect on the second instar larvae of Lasioderma serricorne, in this experiment, 5 strains of Verticillium lecanii and 5 strains of Beauveria bassiana were determined by the impregnation method. Two Beauveria bassiana strains Bb05 and Bbr81 with high virulence to the second instar larvae of Lasioderma serricorne were obtained, and the two strains were prepared into different concentrations of spore suspension, and their virulence was determined. The infection process of the Bb05 strain was observed. The results showed that, at the concentration of 1.0×10⁸ mL^-1, Bb05 had the highest cumulative death rate to L. serricorne (77.78%) and LT₅₀ (8.18 d). The cumulative mortality of strain Bbr81 and LT₅₀ was 74.44% and 7.60 d respectively. After treating the Lasioderma serricorne with different concentrations of spore suspensions, the cumulative mortality increased with the increase of spore concentration and inoculation time. The LC₅₀ of strain BB05 was 8.3×10⁷ spores mL^-1, and that of strain Bbr81 was 1.2×10⁷sporesmL^-1. The two strains were highly virulent to the 2nd instar larvae of tobacco beetle, and have a certain potential for development and application.