IMPACT OF FERTILIZERS AND GREEN ALGAE (SPIROGYRA) ON THE SURVIVAL AND DEVELOPMENT OF IMMATURE MALARIA VECTOR, ANOPHELES GAMBIAE SENSU LATO GILES (DIPTERA: CULICIDAE)

Abstract

Anopheles gambiae is one of the important malaria vectors in Ethiopia. The survival, development and multiplication of the immature stages are determined by different interdependent factors. The application of manures and fertilizers in agro-ecosystem is one of the important factors. A laboratory study was conducted to evaluate the impact of inorganic fertilizer (DAP and UREA 1:1/2 ratio), organic fertilizer (cow dung) and green algae (Spirogyra) against immature An. gambiae. The experiment includes three doses of inorganic fertilizer, cow dung and green algae in 1 L of deionised water prepared in a square tray and 1 L of deionised water alone was considered as control. In the experiment and control group twenty five I, II, III and IVth instar larva was released into individual tray and monitored every 24 h till the completion of their life cycle. The numbers of surviving larval stage was recorded continuously until all the larvae died or emerged into adults. The experimental result revealed that in the case of the tray mixed with 0.75g/L of inorganic fertilizer, the number of adults that emerged from four different larval instar stages was statistically significant (p < 0.05). The number of adults that emerged in high turbidity green algae filament treatment was 95.61 ± 3.86, 93.85 ± 3.30, 90.5 ± 5.43 and 86.84 ± 4.78 from I, II, III and IVth instar larvae respectively. This study concludes that inorganic fertilizer significantly suppressed the survival of An. gambiae immature stage whereas, green algae supported the larval development.