Extraction of mosquitocidals from Ocimum canum leaves for the control of dengue and malarial vectors

ObjectiveTo assess the potentiality of Ocimum canum (O. canum) (Lamiaceae) in larvicidal, pupicidal, adulticidal, and repellent activities against the malarial vector, Anopheles stephensi (An. stephensi) and the dengue vector, Aedes aegypti (Ae. aegypti).MethodsThe mosquitocidal activity of methanol extracts from O. canum against immature and adult An. stephensi and Ae. aegypti (L.) were studied. Standard WHO bioassays were used to evaluate the effectiveness of the plant extract against mosquitoes.ResultsThe methanol extract of O. canum was very effective against the immature stages of An. stephensi (LC50=193.280, 240.551, 303.409, 374.936 and pupa 469.547 mg/L) and Ae. aegypti (LC50=242.071, 287.277, 332.668, 394.061 and pupa 457.879 mg/L). Smoke toxicity assay showed significant mortality rate against adult An. stephensi (86.6%) and Ae. aegypti (84.78%). The number of eggs laid by the females were strictly reduced after exposure to smoke.ConclusionsFrom the observed results we conclude that O. canum can be used as an effective larvicidal and repellent agent against the malarial and dengue vectors.