Studies on the efficacy and persistence of the microbial agent bacillus sphaericus against larvae of culex pipiens pallens.

This paper evaluates the efficacy of the bacterial larvicide bacillus sphaericus strains BS-10 and C3-41, which are isolated in China, as well as BS2362 against larvae of Culex pipiens pallens in laboratory and under field conditions. The results indicate that C3-41 has the highest toxicity with LC50 at 0.0057 ppm and the bacterial formulations are more effective in light polluted water than in heavy polluted one, but the action of B. sphaericus could persist longer in more polluted water.