Repellent Effects of Codium flabellatum and Caulerpa taxifolia Seaweed Extracts on Aedes aegypti

This study investigated the repellency activity of extracts from two green seaweeds, Codium flabellatum(C. flabellatum)and Caulerpa taxifolia(C. taxifolia),against the dengue vector Aedes aegypti. Extraction was conducted using ethanol as the solvent, with subsequent evaluation of repellency through the hand-introducing method. Various concentrations of seaweed extracts (20%, 30% and 40%) were prepared and tested. Results indicated moderate repellent effects across all samples, with the highest repellency observed in C. flabellatumat a 40% concentration, achieving 100% repellency at 6 hours. The LT₅₀ values (lethal time at which 50% of mosquitoes repel due to the applied sample on human skin) showed that C. flabellatumat 40% concentration exhibited the highest repellency (LT₅₀ value: 12 hours) against Aedes aegyptifollowed by Ctaxifolia(LT₅₀ value: 10 hours) at the same concentration. Conversely, a 20% concentration of seaweed extracts demonstrated the most negligible effectiveness, with an LT₅₀ value of 3 hours against Aedes aegypti. These findings suggest that seaweed possesses promising potential as an eco-friendly mosquito repellent and efficient biocontrol agent against mosquitoes.