Efficacy of Bacillus Sphaericus Strain Isolated from North East Region of India as Potential Mosquito Larvicide

Efficacy of Bacillus sphaericus strain GC subgroup IV (Bs) isolated from Assam, India as water dispersible powder formulation has been evaluated in laboratory and field conditions. Laboratory evaluation revealed that Bs, Spherix, ABG 6262 and Bti 164 (serotype H14) produced 90% mortality in Cx. quinquefasciatus @ 0.5, 0.6, 0.75, and 0.7 ppm respectively. In field trial Bs dosage @ 0.1 g/m2 in fresh water ditches resulted in 92.7 % reduction in An. crowfordi and An. annularis larvae whereas, Spherix and ABG 6262 resulted in 82.2 and 78.67 % reduction respectively at same concentration. The application of 0.2 g/m2 dosage in fresh water small ponds Bs, Spherix, ABG 6262 produced 97.43, 85.57, 81.33% reduction respectively in An. vagus and Cx. vishnui larvae. In polluted drains @ 0.5 g/m2 dosage Bs, Spherix, ABG 6262 resulted in 95.57, 86.93, 87.25 % reduction respectively in Cx. quinquefasciatus larvae. The shelf life of Bs was found more and its larvicidal efficacy persisted up to 30 months at room temperature. The study showed that Bs is an effective biolarvicide that can be used in different types of mosquito breeding habitats against different mosquito larvae.