The present invention relates to novel bacteria strains that can be used in biological control against mosquito larvae (Cules spp.) and a method of sequence analysis for the strains. The sequence analysis method comprising genomic DNA extracting, 16S rDNA amplification, a PCR amplification of a 550 bp DNA segment and purifying and sequencing of the DNAs obtain via PCR. The protein obtained from a novel Bacillus sphaericus spp. Isolates with the invention is used as larvicide, the step of isolating the protein at product obtaining stage is eliminated. By means of the invention, the bacterial strains (MBI 5, 6, 7) investigated for biological control of mosquitoes are effective in both polluted and fresh water.