author(s)
P Desiyamani, M Syed Ali, V Anuradha, N Yogananth and H Sheeba

abstract
The present study was conducted to analyze the mosquito larvicidal, repellent and adulticidal activities by ethanol extract of Sargassum polycystum against Aedes aegypti and Culex quinquefasciatus. The larvicidal and repellent activity was tested by various concentrations of the extract at 100, 150, 200, 250 and 300µL/cm² against batches of 20 early fourth-instar larvae of dengue and filariasis vector. Mortality was observed 24h after treatment. Adulticidal activity of S. polycystum extract was tested against 4-5 old female adults of both mosquitoes and mortality was observed 24h under laboratory conditions. The maximum larvicidal and adulticidal activity was observed at 200 µL concentrations of LC₅₀ were (52.2±2.3), (53.2±2.3) and (50.2±0.7), (51.2±0.9) µL/ml. At 300 µL, extracts of S. polycystum showed maximum repellency of 93% and 95.1% against Aedes aegypti and Culex quinquefasciatus. The present study identifies active insecticidal compounds from S. polycystum by GC-MS and can be novel source against dengue and filariasis mosquitoes.