球形芽孢杆菌在死蚊幼体内的再循环及其对持效期的影响

Recycling of Bacillus sphaericus in Mosquito Larvae Cadaver and Its Effect on Persistence

球形芽孢杆菌Ｃ３┐４１杀蚊幼实验制剂对３～４龄致倦库蚊和大劣按蚊幼虫有较强的毒性，其４８小时的ＬＣ５０值分别为０．００７９５和０．９８５００ｍｇ／Ｌ。蚊幼虫死亡后，球形芽孢杆菌芽孢能在死蚊幼体内正常萌发、繁殖和发育，并产生有杀蚊活性的芽孢和晶体混合物。在含有死蚊幼虫的处理组，两种蚊幼虫的死亡率２０天内一直维持在９５％以上；在无死蚊幼的对照组，大劣按蚊幼虫１４天后的死亡率下降为０，致倦库蚊幼虫２０天后的死亡率下降到１０％以下。

acillus sphaericus C3 41 formulation had high toxicity against Culex quinquefasciatus and Anopheles dirus larvae and the LC 5 0 values at 48 h were 0 00795 and 0 98600 mg/L respectively In the larvae cadaver, B sphaericus spores germinated, developed normally and produced recycling spores and crystal complex with high activity Laboratory experiments proved that the cadavers played an important role in the long persistence of B sphaericus in water When mosquito cadavers were added into the water the mortality of the larvae remained over 95% during the 20 d experimental period While in the water without cadaver the mortality of A dirus and C quinquefasciatus decreased rapidly from nearly 100% on the second day to zero at the end of the experiment