蚜小蜂和粉虱座壳孢对烟粉虱的控制作用研究

研究了烟粉虱两种寄生性天敌桨角蚜小蜂(Eretmocerus sp．)和粉虱座壳孢(Aschersonia aley-rodis)单独使用和联合使用时对烟粉虱种群的控制作用。结果表明，在单独进行控制时，在一个世代内按5×10^6个孢子·ml^-1喷施粉虱座壳孢2次，对烟粉虱种群的控制作用达95．74％，按每株植株3头雌蜂的密度释放桨角蚜小蜂2次，对烟粉虱种群的控制作用达57.58％。在两者联合控制时，一个世代内喷施粉虱座壳孢2次，再释放桨角蚜小蜂1次或2次，对烟粉虱种群的控制作用达97．02％～97．91％，烟粉虱种群增长趋势指数低于1，种群数量逐渐下降，联合使用时，桨角蚜小蜂和粉虱座壳孢间无消极影响。

Effectiveness of Eretmocerus sp. And Aschersonia aleyrodis in controlling Bemsia tabaci populations

The effectiveness of Eretmocerus sp. and Aschersonia aleyrodis in controlling Bemisia tabaci populations on cucumber were determined in separated and combined greenhouse experiments. The results showed that after spraying A. aleyrodis (5 x 10(6) spores per ml, twice per generation) and releasing Eretmocerus sp. (3 female per plant, twice per generation), 95.74% and 57.58% of whitefly populations were controlled, respectively. However, when the two natural enemies were used together with the same rate mentioned above (A. aleyrodis spraying twice followed by releasing Eretmocerus sp. once or twice in one generation), 97.02%-97.91% of whitefly populations were controlled. Moreover, the increasing index of whitefly population (I) subjected to both natural enemies together was below I, indicating the substantial reduction in whitefly population. The combined treatments provided a better control effect of whitefly than separated ones, and there was no contradicted effect between both natural enemies.