Abstract:
Controlling mosquitoes at the larval stage is an effective measure to prevent mosquito-borne diseases. Chemical larvicides are known to raise several environmental and public health concerns; thus, non-toxic and biodegradable plant-based larvicides are becoming popular. The present study tested the larvicidal activity of Citrus microcarpa (calamansi) and Citrus maxima (suha) rinds against the third-instar larvae of Aedes aegypti by measuring their LC50 and LC90. Simple distillation was employed for the extraction of the essential oils. Larvicidal bioassays showed that Citrus maxima has a stronger larvicidal effect (LC50 of 26.13 ppm and LC90 of 49.34 ppm) than Citrus microcarpa (LC50 of 53.10 ppm and LC90 of 81.38 ppm). The percentage compositions of their bioactive substances, analyzed by gas chromatography, revealed limonene to be the dominant component in both essential oils, though higher in Citrus maxima (95.5%) than Citrus microcarpa (91.6%). The stronger larvicidal property of Citrus maxima can be attributed to the higher limonene content in its essential oil compared to Citrus microcarpa.
