球孢白僵菌对葱地种蝇成虫的毒力及繁殖力的影响

Virulence of Beauveria bassiana to Adults of Delia antiqua(Meigen) and Effects on Their Reproduction

本文采用浸虫法测定了4株球孢白僵菌对1日龄葱地种蝇(本文称葱蝇)成虫的毒力,筛选出高致病力的菌株,描述了感染症状,测定了其亚致死剂量LC20和LC50对存活1日龄葱蝇成虫生物学参数和繁殖力的影响,并比较了5.8×103和5.7×105孢子/m L对1日龄和10日龄葱蝇成虫死亡率和单雌产卵量的差异。结果表明菌株Bb01对葱蝇成虫的致病力最强,其LC50为1.76×106孢子/m L,其次为菌株Bb03和Bb02,其LC50分别为4.05×106和1.86×107孢子/m L。与对照相比,菌株Bb01亚致死剂量处理1日龄成虫后,明显延迟了葱蝇成虫的产卵前期,降低了单雌产卵量,LC20浓度处理时单雌产卵量比对照下降了51.9%,LC50处理下降92.2%,明显缩短了雌成虫寿命,但卵孵化率没有明显影响。虽然菌株Bb01对1日龄成虫造成的死亡率较高,但在5.7×105孢子/m L下,10日龄成虫单雌产卵量比对照下降了82.5%,对种群控制效果仍较强。

The virulence of 4 strains of Beauveria bassiana to 1-day-old Delia antiqua（Meigen） adults was detected with insect-dipping method to screen out strains of high pathogenecity. The reproduction and biological parameters were measured to D. antiqua treated with the sublethal dose LC20 and LC50, and effects of the strains on mortality and fecundity of age-specific D. antique adults were compared between treatments by 5.8×10^3 and 5.7×10^5 conidia/m L concentrations. The strain B. bassiana Bb01 showed the highest virulence against D. antique, with LC50 of 1.76×10^6 conidia/m L, followed by B. bassiana Bb03 and Bb02, with LC50 of 4.05×10^6 and 1.86×10^7 conidia/m L, respectively. B. bassiana Bb01 extended preoviposition period of 1-day-old D. antiqua adults and reduced their fecundity by 51.9% and 92.2% at LC20 and LC50 compared with the control, respectively. B. bassiana Bb01 shortened longevity of female adults significantly, while had no effect on egg hatching rate. Although Bb01 caused higher mortality in 1-day-old adults than in 10-day-old adults, fecundity of 10-day-old adults was reduced by 82.5% at 5.7×10^5 conidia/m L of Bb01 compared with the control.