Isolation of a Novel Mosquitocidal Bacterium Bacillus cereus VCRC-641 from Fresh Water Fish Clarias batrachus

In this study, search for new mosquitocidal bacterium was attempted from the gut content of the fresh water fish Clarias batrachus (walking cat fish) which resulted in the isolation of a highly potential mosquitocidal bacterium. The isolate was identified as Bacillus cereus VCRC 641 by Bacillus species specific molecular markers ilvD, pur and pycA gene sequence analysis. Laboratory mosquito larval toxicity assay (bioassay) against mosquito larvae revealed that this new isolate was highly potent against Culex quinquefasciatus followed by Aedes aegypti and Anopheles stephensi. The lethal concentration values at LC₅₀ for these three mosquito species were 0.001, 0.004 and 0.007mg/L respectively. Therefore, in the present study, this is the first report that a highly potential mosquitocidal bacteria of B. cereus VCRC 641 was isolated from the gut content of Clarias batrachus and suggested that it can be used for mosquito vector control program.