Biocontrol Potential of Bacillus thuringiensis Isolated from Soil against Mosquito Larva

A major challenge for achieving successful mosquito control is overcoming insecticide resistance. This study was carried out to assess the larvicidal activity of Bacillus thuringiensis isolated from different soil samples within Sokoto metropolis using standard methods. Confirmatory identification of the organism was made based on biochemical characterization and microscopic observation. The larvicidal activity of Bacillus thuringiensis isolated were tested against the larva of mosquito using three dilutions of the Bacillus culture in a bioassay. The isolated organisms were confirmed as Bacillus thuringiensis. The result of the bioassay showed variation in the level of efficacy of the bacteria and depended on the time of the exposure. Mortality rate greater than 20% was observed after 60 minutes and increased to 100% after time of exposure was increased for all dilutions of B. thuringiensis used. The results showed that Bacillus thuringiensis toxins can be bacteriocidal to mosquito larvae in a matter of minutes depending on the concentration ingested by the larvae. This, in essence, proved that Bacillus thuringiensis is an effective bio-larvicide that can be used to reduce and possibly eradicate the nuisance of disease-causing mosquitoes and aid in the rollback of malaria.