Occurrence and Distribution of Mosquitocidal Bacillus sphaericus in Soil

Abstract

2 Abstract: A major challenge for achieving successful mosquito control is overcoming insecticide resistance. Bacillus sphaericus is one of the effective biolarvicides to control Culex species and the monitoring of larval susceptibility is essential to avoid resistance development. Mosquito larvicidal activity of B. sphaericus was assessed by isolating them from ecologically different soil habitats in and around Devakottai of Tamil Nadu in South India. The isolated organisms were confirmed as Bacillus sphaericus based on biochemica l characterization and microscopic observations. The larvicidal activity of B. sphaericus isolates was tested against the larvae of Culex quinquefasciatus by using the standard cup bioassay. The isolates of B. sphaericus showed a significant level of variation in their larvicidal activity. 16s rRNA typing analysis was also carried out for highly toxic selected mosquito larvicidal isolate of Bacillus sphaericus to confirm its species identification.