Abstract:
The essential oil extract from the leaves of Blumea balsamifera L. was tested for its larvicidal activity against third and fourth instar larvae of Aedes aegypti, the primary vector of the dengue virus. The essential oil was obtained via hydrodistillation using a Clevenger-type apparatus. Essential oil concentrations used for the larvicidal assay were 100, 125, 150, 225, and 300 ppm. Larval mortality was observed after 24 hours of treatment. The LC50 values of B. balsamifera essential oil against third and fourth instar larvae of Ae. aegypti after 24 hours of exposure were 148.10 ppm and 140.53 ppm, respectively while the LC90 values for third and fourth instar larvae were 275.67 ppm and 212.35 ppm, respectively. No mortality was observed in the negative control with DMSO. The LC50 values of Abate 1SG against third and fourth instar larvae were 0.218 ppm and 0.252 ppm, respectively while LC90 values for third and fourth instar were 0.417 ppm and 0.398 ppm, respectively. These findings suggested that the commercial larvicide was still more potent in comparison to the essential oil as its aforementioned LC50 and LC90 values were lower by 99.8% as compared to the values observed from the essential oil. Thus, the sambong leaf essential oil exhibited good larvicidal activity and may be utilized to lessen the frequency of synthetic larvicide usage, which could delay the rapidly evolving resistance of mosquitos against synthetic larvicides due to the over dependence and repeated use of these products.
