Abstract:
The use of synthetic larvicides as a means of controlling the mosquito population can cause
detrimental effects to the environment and non-target organisms. Plant-based larvicidal
alternatives are therefore being developed as they are safer to the environment and the
public. This study aims to assess whether the ethanolic extract of Terminalia microcarpa
Decne leaves will be able to cause the mortality of Aedes aegypti larvae and to determine
the phytochemicals present in T. microcarpa Decne leaves. Collected leaf samples were
air dried and extracted with ethanol. A qualitative analysis was performed in order to
identify the secondary metabolites present. A modified larvicidal bioassay was used to
evaluate the larvicidal activity of the extract at 5% v/v, 2% v/v, and 1% v/v
concentrations.The positive and negative control used were Piper nigrum and distilled
water, respectively. The results of the qualitative analysis showed presence of glycosides,
flavonoids, saponins, phytosterols, and tannins in T. microcarpa leaves. Complete larval
mortality was exhibited at 5% v/v concentration on the 24th and 48th hours. Larval mortality
at 2% v/v concentration on the 24th and 48th post-exposure is 96.67% and 100%,
respectively. At 1% v/v concentration, the larval mortality on the 24th and 48th hour postexposure
is 46.67% and 86.67%, respectively. The lethal concentrations LC50 and LC90 on
the 24th hour post-exposure was found to be at 1.03% v/v concentration and 1.59% v/v
concentration, respectively. The crude ethanolic extract of T. microcarpa Decne leaves may
be a potential larvicide for A. aegypti mosquito larvae.
