Phytochemicals as natural fumigants and contact insecticides against stored-product insects.

Abstract

Abstract For centuries, traditional agriculture in developing countries has used effective methods of insect pest control using botanicals. In order to make them a cheap and simple means of insect control for users, their efficacy and optimal use still need to be assessed. Currently, the measures to control pest infestation in grain, dry stored food and cut flowers rely heavily on toxic fumigants and contact insecticides. In recent years, the number of pesticides has declined as health, safety and environmental concerns have prompted authorities to consider restricting the use of toxic chemicals in food. Lately a new field is developing on the use of phytochemicals in insect pest management, such as edible and essential oils and their constituents. The aim here has been to evaluate the potential use of edible oils obtained from oil seeds and essential oils, and their constituents obtained from aromatic plants, as fumigants and contact insecticides for the control of the legume pest Callosobruchus maculatus F. (Coleoptera: Bruchidae). The most active edible oils as contact insecticides were crude oils from rice, maize, cottonseed and palm, and the fatty acids capric acid and undecanoic acid. The essentials oils and their constituents were found to have higher activity as fumigants than contact insecticides. From our studies, to elucidate the mode of action of essential oils, it was possible to postulate that essential oils may affect octopaminergic target sites.