Repellency and toxicity of aromatic plant extracts against the mosquito Culex pipiens molestus (Diptera: Culicidae)

Abstract

The insecticidal activities of essential oil extracts from leaves, flowers and roots of aromatic plants against fourth-instar larvae of the mosquito Culex pipiens molestus Forskål were determined. Extracts of Foeniculum vulgare Mill were the most toxic, followed by those of Ferula hermonis Boiss, Citrus sinensis Osbeck, Pinus pinea L, Laurus nobilis L and Eucalyptus spp with LC₅₀ values of 24.5, 44.0, 60.0, 75.0, 117.0 and 120.0 mg litre⁻¹, respectively. Combination tests between the LC₅₀ and the maximum sub-lethal concentration (MSLC) were determined. Over 20 major components were identified in extracts from each plant species tested. Five essential oils and nine pure components were studied for their repellency against mosquito bites. Terpineol and 1,8-cineole were the most effective against Culex pipiens molestus bites offering complete protection for 1.6 and 2 h, respectively. Copyright © 2005 Society of Chemical Industry