Larvicidal effect of varying concentrations of adelfa (Nerium oleander) leaf aqueous infusion on Aedes aegypti

Abstract

Background: The current use of synthetic insecticides to control mosquito borne diseases such as Dengue Hemorrhagic Fever has created harmful effects on the environment. Hence, the search for biodegradable and less toxic insecticides from plant sources is beneficial.

Objective: This study aimed to determined the larvicidal effect of varying concentrations of Adelfa (Nerium oleander) leaf infusion on Aedes aegypti larvae. Specifically, this was conducted to determined the LC50 and LC90 of Adelfa infusion.

Methods: The experimental method of investigation was utilized in this study. The study was conducted in Jaro, Iloilo City. Third instar A. aegypti larvae were used as subjects. The A. aegypti larvae were exposed to four different concentrations (25%, 50%, 75% and 100% ) of Adelfa (N. oleander) leaf infusion. Malathion served as positive control. Tap water was used as negative control. The larvicidal effect of Adelfa was based on the percentage mortality of A. aegypti larvae after 24 hours of exposure and the lethal dose of the leaf infusion.

Results: After 24 hours of exposure, a high mortality of A. aegypti was observed after exposure to 50%, 75% and 100% concentration of N. oleander leaf infusion. Analysis showed that there was a significant difference between the mean scores of the control group and the means scores of the treated group. Increase in concentration correspondent to increase in mortality of A. aegypti. It needed 42.33% concentration N. oleander to kill half of the population of A. aegypti larvae.

Conclusion: Adelfa (N. oleander) leaf aqueous infusion has a concentration dependent larvicidal effect against A. aegypti . The LC50 and LC90 of N. oleander are 42.33% and 77.85%, respectively.

Keywords: Larvicidal, Nerium oleander, Aedes aegypti, lethal concentration