不同接种方式下球孢白僵菌对小菜蛾的致病力

本文比较了4种接种方式下球孢白僵菌Bb02菌株对小菜蛾2龄和3龄幼虫的致病力。当孢子悬浮液浓度为1×107个/mL时,球孢白僵菌对小菜蛾2龄幼虫校正死亡率为浸虫法73.79%,涂抹法68.28%,喷雾法51.72%和浸叶法33.79%;对3龄幼虫的校正死亡率为喷雾法57.93%,浸虫法57.24%,涂抹法55.86%和浸叶法28.28%,虽然浸虫法的校正死亡率稍低于喷雾法,但两者差异不显著。同时,2龄和3龄幼虫以浸虫法处理僵虫率最高,分别达31.25%和29.55%;致死速度最快,LT50分别为3.62 d和4.63 d。认为浸虫法最适于室内准确评价球孢白僵菌对小菜蛾的致病力。

Pathogenicity of Beauveria bassiana to diamondback moth by using different inoculation methods

The pathogenicity of Beauveria bassiana strain Bb02 against the second and third instar larvae of the diamondback moth, Plutella xylostella L., was investigated by using four inoculation methods in the laboratory. It was shown that the mortality of larvae varied with different inoculation methods at a concentration of 1×107 conidia/mL suspension. The highest mortality 73.79% of second instar larvae was obtained by insect immersing method, compared to other inoculation method (68.28% by insect smearing, 51.72% by insect spraying and 33.79% by cabbage leaf immersing). However, there were no significant differences between the highest mortality 57.93% by insect spraying method and 57.24% by insect immersing method, when third instar larvae was provided. Insect immersing method had also resulted in the highest total cadaver rates (31.25% of second instar larvae and 29.55% of third instar larvae) and the shortest LT50 values (3.62 days of second instar larvae and 4.63 days of third instar larvae) after treatment in the bioassay. It was indicated that insect immersing method was the most effective inoculation method in the bioassay in assessing the pathogenicity of B. bassiana against the diamondback moth.