Isolation of Entomopathogenic Lysinibacillus sphaericus from Sewage at Some Housing Complex in Mataram City and Evaluation of Its Toxicity Against Aedes aegypti Larvae in Laboratory

Abstract

The aims of this study were to isolate Lysinibacillus sphaericus from sewage at some housing complex in Mataram city and evaluate its toxicity against third Aedes aegypti larvae. The bacteria collected from mud taken from diluted sewage and objected to heat shock procedure at 80oC for 30 minutes. The microbiological culture was done using a Nutrient Agar solid medium and incubated at 30oC for 72 hours. Bacterial characterization was done based on bacterial colony morphology, cell morphology, cell physiology, and cell biochemistry characteristics. Toxicity test on 3rd Aedes aegypti larvae was done for 24, 48, and 72 hours applying Nutrient Broth medium with various dilution. From this study total of 11 isolates of Lysinibacillus sphaericus were isolated, only three isolates showed a high killing rate against Ae. aegypti in 24-hour observation. They were isolate Bs9-2-3 (LC50 24-hour value was 1.75 x 10 cell/mL), isolate Bs9-1-5 (LC50 24-hour value was 6.23 x 10 cell/mL) and isolate Bs2-1-2 (LC50 24-hour value was 7.17 x 10 cell/mL). These local isolates of L. sphaericus had good potential to be developed for bacterial-based biopesticide/biolarvicide for battling Aedes mosquito larvae in the near future.