Abstract
The aims of this study were to design an effervescent preparation using Bacillus sphaericus locally-isolated from lombok island previously grown on fish flour medium and to evaluate the toxicity of the preparation against field-captured 3rd instar Anopheles larvae. B. sphaericus was grown on fish flour medium at 30°c for 72 hours. The culture was dried and mixed with effervescent components (consisting of citric acid, tartaric acid, and calcium bicarbonate) in five combinations. From the five combinations, two combinations, namely combination 4 (10% citric acid : 10% tartaric acid : 55% calcium bicarbonate : 25% B. sphaericus) and combination 5 (5% citric acid : 5% tartaric acid : 65% calcium bicarbonate : 25% B. sphaericus), were effective in killing Anopheles larvae in the first 24 hours of observation. Besides effective larval killing, they both showed the fastest starting bubbling time and bubbling duration when put in water. In conclusion, fish flour medium combined with effervescent materials could be used to develop B. sphaericus-based bio-larvicidal preparations to control 3rd instar Anopheles larvae in a laboratory experiment.