Larvicidal Potential of Conidia Suspension of Aspergillus flavus against Anopheles sp.

Abstract

Aim: This study was aimed to investigate the larvicidal potential of the conidia suspension of Aspergillus flavus against Anopheles mosquitoes. Methods: Aspergillus flavus was isolated from soil using soil suspension procedures and was identified using morphological characteristics. Bioassay was performed to determine the efficacy of Aspergillus flavus conidial suspension against early 4th instar larvae of Anopheles mosquito using WHO-2005 protocol with slight modifications. Results: Four different concentrations of conidial suspension; 3.3×106, 3.3×105, 3.3×104 and 3.3×103conidia/ml were tested, and the results showed that; mortality increases with the increase in conidial concentrations and exposure time. The lowest mortality (12%) was recorded at 3.3×103 conidia/mL and 24-hours post exposure whereas the highest mortality (78%) was recorded at 3.3×106 conidia/mL and 72-hours post exposure. LC 50% and 90% for the larvae was found to be 1.6×108 and 4.2×109conidia/mL at 24-hours; 2.0×104 and4.0×105 conidia/mL at 48-hours; 1.3×103 and 3.2×104 conidia/mL at 72-hours. Conclusion: These results indicated that Aspergillis flavus conidia suspension are pathogenic to immature stage of Anopheles mosquito and could be suggested as a biological control for mosquito management.