Larvicidal activity of Citrofortunella microcarpa (Lemonsito) and Carica papaya (papaya)extracts against the dengue-vector mosquito, Aedes sp.

Abstract

This study investigated the larvicidal activity of the methanolic leaf extract of Citrofortunella microcarpa and Carica papaya against the dengue-vector, Aedes sp. mosquito. Qualitative phytochemical screening was performed to identify the bioactive chemicals present in the extract and a larvicidal assay was performed against the third instar larvae of Aedes sp. to determine the efficacy of the plant extracts at 6 mg/mL, 12 mg/mL and 18 mg/mL concentration. Data on the mortality of mosquito larvae after 24 and 48 hours were analyzed using the arithmetic mean, Tukey test and t-test. Results from the assay revealed that both plants possessed a larvicidal potential. However, lemonsito demonstrated a concentration dependent effect and a significantly higher larvicidal activity at 0.05 level of significance compared to papaya. This larvicidal property can be attributed to the presence of known insecticidal and larvicidal phytochemicals in both plants extracts namely: the alkaloids, flavonoids, saponins, steroids and tannins. In addition, fatty acid was identified to be present in lemonsito extract which may produce a synergistic effect with other abundant phytochemicals hence a higher larvicidal activity.