球孢白僵菌HFW-05对烟粉虱的致病力及组织病理影响

摘要

Temperature and humidity are key factors to affect the pathogenicity of Beauveria bassiana HFW-05. The pathogenicity of B. bassiana to Bemisia tabaci nymphs under different temperatures and humidities were studied in the laboratory. The histopathological changes of B. tabaci nymphs infected by strain HFW-05 also were observed. The corrected mortality of each period of B. tabaci nymphs treated by strain HFW-05showed the same curves. The infection peak day of different instar nymphs appeared on the 3rd-4th day after inoculation. The LC50 of the first to the third instar nymphs were 5.94×10 4,1.06×10 5 and 5.08×10 5conidia/mL , respectively. The LT50 were 2.54 d,2.68 d and 3.18 d, respectively. It showed very low pathogenic activity to the egg which infection rate was 24.9% after 6 d inoculation with 1×10 8conidia/mL concentration. Strain HFW-05 showed the highest pathoginicity to B. tabaci nymphs at 25℃ and 30℃. The pathoginicity of HFW-05 decreased when the temperature <25℃ or >30℃. The mortalities of the B. tabaci nymphs under different humidities showed significant differences. The nymphs died most quickly and the mortality was the highest under above 90% relative humidity, while the mortality decreased drastically under 70%-90% relative humidity. The mortality was about 60% under below 70% relative humidity. The conical lingula of B. tabaci nymphs was the most important invasive part. B. bassiana HFW-05 has the potential to be used for biological control against B. tabaci.%环境温湿度是影响白僵菌菌株致病力的关键因素,本文测定了不同温、湿度下白僵菌Beauveria bassiana HFW-05对烟粉虱Bemisia tabaci若虫及卵的致病力,同时观察了烟粉虱感病若虫的组织病理变化.结果表明,各浓度下烟粉虱若虫的校正死亡率随时间变化曲线基本一致,接种3-4 d时出现死亡高峰,白僵菌HFW-05对烟粉虱1龄、2龄、3龄若虫的LC50分别为5.94×10 4、1.06×10 5、5.08×10 5孢子/mL,LT50分别为2.54 d、2.68 d、3.18 d;白僵菌HFW-05对卵的致病力很低,1×10 8孢子/mL接种浓度下,卵的6 d感染率仅为24.9%.在25℃、30℃下,HFW-05对烟粉虱若虫表现出最强的致病力,高于或低于此温度时,烟粉虱若虫死亡速度减慢,死亡率降低.相对湿度发生变化时,烟粉虱若虫死亡速度和死亡率明显不同,相对湿度高于90%时,烟粉虱若虫死亡速度最快,死亡率最高,相对湿度介于70%-90%时,白僵菌HFW-05对烟粉虱若虫的致病力无明显差异,但校正死亡率显著低于环境湿度大于90%的处理,相对湿度低于70%时,烟粉虱死亡率也达到60%左右.组织病理学观察显示尾部舌状突是HFW-05侵染烟粉虱若虫的关键部位.研究结果表明白僵菌HFW-05在烟粉虱的生物防治中有较大的潜力.