Efficacy of a Locally Isolated Strain of Bacillus cereus as Mosquito Larvicide

Isolation and characterization of a soil bacterial strain were done and its dose dependant larvicidal efficacy against immatures of Culex quinquefasciatus was evaluated in laboratory and field conditions. N was isolated from soil samples of Burdwan district, West Bengal, India. Morphological, biochemical and physiological characteristics were studied and 16S rDNA gene sequence alignment was done for taxonomic identity of the strain with the establishment of a dendogram. Laboratory bioassays were conducted to evaluate the larvicidal properties with the active formulation. The experiment was further detailed in field conditions to evaluate the larvicidal efficacy of the active formulation with determination of LC50 values and quantification of costing effects on non-target water fauna. 16S r-DNA gene sequence analysis showed that this isolate N belongs to Bacillus cereus. The bioactive formulation of this isolate showed efficient larvicidal activity both in laboratory (LC50=0.45 mg/dl, 0.53 mg/dl, 0.65 mg/dl and 0.76 mg/dl for 1st, 2nd, 3rd and 4th instars larvae respectively) and field conditions. The soil isolated bacterial strain showed potential of a biocontrol agent against mosquito immatures. Keywords Soil isolated bacterium (N); Culex quinquefasciatus; Mosquito larvae; Biocontrol agent; Field experiment