Testing the insecticidal activity of five different essential oils against bean weevil(Acanthoscelides obtectus [Say], Coleoptera, Chrysomelidae) adultsunder laboratory conditions

Abstract: Fumigant toxicity of essential oils from Rosmarinus officinalis, Salvia officinalis,Laurus nobilis, Citrus bergamia, and Cinamomum camphora against Acanthoscelides obtectusadults reared on common bean seeds was assessed. Properties of essential oils were tested at twodifferent dose rates (245 and 980μl/l). Insecticidal efficacy was tested at five differenttemperatures (15, 20, 25, 30, and 35°C) and two relative humidity (RH) levels (55 and 75%).Responses varied with type of essential oil, time of exposure, dose of essential oil, as well as withtemperature and relative humidity levels. Three days after treatment over 90% adult mortalitywas achieved. An essential oil from rosemary gave over 94% efficacy after three days. At 75%relative humidity essential oils were significantly more effective than at 55% relative humiditylevel. The plant essential oils described in this paper could be useful for managing populations ofA. obtectus in warehouses.