关键词: 球形芽孢杆菌C3-41菌株, 致倦库蚊, 再循环

Abstract: The efficacy of Bacillus sphaericus C₃-41 to control the larvae of Culex quinquefasciatus was evaluated in the laboratory. The result indicated that the strain C₃-41 was a very effective control agent against the mosquito larvae. The 50% lethal dosage (LD₅₀) against the second to fourth larval instar were found to be 63.1 and 89.7 sporesper larva respectively. The larvicidal substance ingested by larvae seemed to be directly proportional to the concentration of C3-41 and duration of feeding time. When larvae ingested subAethal dosage of B. sphaericus, its recycling could not occur in the living larvae. However, when the larvae ingested lethaldosage, they died within 48 hours and recycling of the bacteria occurred immediately. The number of spores increased from initial 1.86X10²to1.59X10⁶ sporesper larva within six days after the death of the larvae. The spores germinated, multiplied, sporulated and forming toxin normally in larval cadavers. The spores yielded in larval cadavers were highly toxic to the mosquito larvae.

Key words: Bacillus sphaericus C₃-41——Culex quinquefasciatus——recycling