【摘要】 研究了球形芽孢杆菌BacillussphaericusC3 4 1菌株对致倦库蚊Culexquinquefasciatus幼虫的毒力及其后致死作用。生物测定表明 ,该菌株对目标蚊幼虫具有很高的毒力 ,其丙酮粉剂对 3～ 4龄幼虫 4 8h的半致死浓度 (LC50 )为 (6 92± 0 2 2 ) μg L。用不同亚致死浓度处理 2～ 3龄致倦库蚊幼虫 ,存活幼虫在后期发育中存在明显的延续死亡和损伤现象 ,经LC3 0 、LC50 、LC70 、LC90 和LC98剂量的C3 4 1粉剂处理的致倦库蚊羽化前的总死亡率分别为 84 %、 91%、 95 %、 97%和 10 0 %,同时存活的幼虫、蛹和成蚊的发育和行为也受到一定的影响。这种后致死作用随处理浓度的升高而增强 ,可能同球形芽孢杆菌毒素蛋白对处理期间蚊幼虫中肠上皮细胞造成的损伤相关。更多还原

【Abstract】 The toxicity and the delayed effects of Bacillus sphaericus C3-41 to \%Culex quinquefasciatus\% larvae has been studied.The bioassay results indicated that the C3-41 acetone powder has a considerable toxicity against target under the laboratory condition, with a fifty percent lethal concentration (LC 50 ) of 6 92±0 22 μg/L against 3 rd ～4 th instar larvae at 48 h. The significant continued mortalities and abnormal development were observed in larval, pupal and emergence stages after the initial 48 h exposure of larvae were terminated, and the cumulative preadult corrected mortality of LC 30 , LC 50 , LC 70 , LC 90 , LC 98 dosage treatment were 84%, 91%, 95%, 98% and 100% respectively. In comparison, only 5% cumulative preadult corrected mortality was observed in control. Moreover, the delayed pupation, abnormal emergence and delayed oviposition were also noticed in surviving treated individuals. These long-term effects of C3-41 to mosquito larvae may be resulted from the damage of the midgut epithelium caused by binary toxins in initial treatment and would be contributed a great deal to the efficacy of B. sphaericus in field application for mosquito control.更多还原