The ability of plant essential oils to enhance different synthetic pyrethroids against Aedes aegypti and Anopheles gambiae

The burden of mosquito-borne diseases to public health throughout the world cannot be underestimated. Every year, approximately 700,000 people die from complications associated with etiologic disease agents transmitted by mosquitoes. With insecticide-resistant mosquito populations becoming an ever growing concern, the need for new insecticidal formulations is more important than ever. We screened mixtures of various synthetic pyrethroids (permethrin, deltamethrin, B-cyfluthrin, and natural pyrethrins) with various essential oils in order to enhance the efficacy of these pyrethroid insecticides. We have previously shown that some commercially available essential oils have the ability to enhance the mortality caused by the synthetic pyrethroid, permethrin. We have demonstrated that many plant essential oils are capable of differentially enhancing various synthetic pyrethroids. We have begun enriching fractions of these essential oils with the hope of relating bioactivity to particular terpenoid compounds. Essential oils are composed of plant-derived compounds, some of which have been demonstrated to possess novel modes of action. These compounds could represent new chemistries for use in insecticide formulations that could improve efficacy of synthetic insecticide against resistant mosquito populations, reduce the overall amount of synthetic insecticides used throughout the world, and demonstrate novel insecticidal mechanisms not yet explored in insect toxicology.