蜡蚧轮枝菌VL17菌株代谢产物对桃蚜若蚜的室内毒力

蜡蚧轮枝菌(Verticillium lecanii)VL17菌株液体发酵滤液,经乙酸乙酯萃取并旋转蒸发后,获得粗毒素。采用浸渍法测定粗毒素对桃蚜(Myzus persicae)的毒力。结果表明:0.375mg/mL粗毒素对桃蚜若蚜的LT50为8.3821d,随浓度增加其杀虫速度加快;处理试虫第3天,粗毒素对桃蚜若蚜的LC50为3.9661mg/mL,随处理时间延长其毒力增强。

Laboratory toxicity of metabolic products from Verticillium lecanii VL17 strain to nymphs of Myzus persicae

Crude toxic was obtained from culture filtrate of Verticillium lecanii VL17 strain by extracted with eth-yl acetate and evaporation. Activity of the crude toxic to nymphs of Myzus persicae was tested with dipping meth-od. The results indicated that the LT_(50) reached to 8.382 1 d when the concentration of crude toxic was 0.375 mg/ mL, and the LT_(50) value was declined with increasing crude toxic concentrations. Three days after treated by the crude toxic, the LT_(50) was 3.966 1 mg/mL, and the toxicity of the crude toxic increased with extending treatment time.