Impact of Fresh and Powdered Extracts of Azolla pinnata on Larval Mortality, Oviposition and Ovicidal Activity on Aedes aegypti Mosquitoes

Abstract

 This study was carried out at Zaki and Katagum Local Government Areas of Bauchi State, Nigeria. The study aimed to assess the impacts of fresh and powdered extracts of Azolla pinnata on larval mortality, Oviposition and Ovicidal activity of Aedes aegypti. Eight (8) concentrations of five replicates were used for the experiment. The doses were; 500, 600, 700, 800, 1000, 1500, and 1700 mg/L respectively. Samples of A. pinnata were taken, laboratory-dried, mixed, and sieved into a fine powder. Larvicides bioassays were conducted in compliance with the World Health Organization recommendation protocol. To test for larval susceptibility, five replicates of A. aegypti larvae were exposed to powdered and fresh A. pinnata at varying doses for 24hours. A egypti gravid females, consisting of five replicates, were used to perform the Oviposition deterrent.  However, five replicates of each concentration was used to test the ovicidal action. Microscope was used to count the egg in each treatment the eggs were moved into a cup filled with distilled water to monitor hatching. 48 hours after treatment, hatch rates and the proportion of eggs that died were evaluated. Mortality was subjected to log-probit analysis in order to calculate LC₅₀ and LC₉₀ with a 95% confidence limit. Utilizing formulas, ovicidal activity and oviposition deterrent were determined. With increasing concentrations in both treatments, there was a discernible rise in mortality. For fresh and powdered A. pinnata extracts, the oviposition deterrence assay demonstrates effective repellency at 100% for concentrations of 700 mg/L, 800 mg/L, 1000 mg/L, 1500 mg/L, and 1700 mg/L. Ovicidal activity revealed that 81%, 85%, 91%, and 97% of Aedes aegypti eggs died when submerged in trays containing both extracts. Aedes egg hatchability ranged from 96% to 100% in the control treatments.  The result of this study shows that A. pinnata crude extracts, both fresh and powdered, were efficient and might be used as an insecticide for the control.