不同温、湿度下白僵菌对棉铃虫幼虫的致病力

测试了不同温、湿度下白僵菌Beauveria bassiana对棉铃虫Helicoverpa armigera幼虫的致病力。实验设置了10、15、20、25、30℃ 5个温度水平，用高浓度（1×10<.sup8孢子/mL）、中浓度（1×10⁷孢子/mL）、低浓度（1×10⁶孢子/mL）的白僵菌孢子液分别感染1～4龄的棉铃虫。结果表明：三个浓度处理的棉铃虫在温度为25℃时的致死中时（LT₅₀）最短，死亡速度最快，死亡率最高；高于或低于此温度时，棉铃虫的LT₅₀延长，死亡速度减慢。相对湿度发生变化时，感病棉铃虫死亡速度和死亡率明显不同。相对湿度为95%左右时，棉铃虫死亡速度最快，死亡率最高；相对湿度低于70%时，棉铃虫死亡率显著降低。

The pathogenicity of Beauveria bassiana to Helicoverpa armigera under different temperatures and humidities

The pathogenicity of Beauveria bassiana to Helicoverpa armigera under different temperatures and humidities was studied in the laboratory. The 1～4 instar larvae of the cotton bollworm were infected with different concentrations of B. bassiana under 10, 15, 20, 25 and 30℃ conditions. The results showed that under 25℃, the LT₅₀s of the larvae treated with three different concentrations of B. bassiana were the shortest， the larvae died most quickly and the mortalities were the highest. The LT₅₀s were prolonged as the ambient temperature turned-higher or lower than 25℃, and the larvae died slowly under these temperatures. There were significant differences among the mortalities of the cotton bollworm under different humidities. The larvae died most quickly and the mortality was the highest under 95% relative humidity, while the mortality decreased drastically under 70% relative humidity.