Fumigant toxicity of some plant essential oils to Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae)

The fumigant toxicity of five plant essential oils (Foeniculum vulgare Miller, Lavandula stoechas L., Thymbra spicata L., Teucrium polium L. and Heracleum platytaenium Boiss.) were tested on Acanthoscelides obtectus (Say) (Col.: Bruchidae) under laboratory conditions. Single dose (100 mu l/L) of plant essential oils were initially tested on adult stage of A. obtectus. The greatest fumigant toxicity against A. obtectus was seen with F. vulgare essential oil, followed by T. spicata and L. stoechas essential oils. In the dose response bioassays with F. vulgare, T. spicata and L. stoechas, the calculated LC50 values were 22,3 mu l/L, 32,4 mu l/L and 46,3 mu l/L respectively. The main components of plant essential oils of three plants showing high response were determined by GC-MS analysis. F. vulgare essential oil's main components were anisole (79%) and L-Fenchone (13%). T. spicata and L. stoechas contain L-Fenchone (55%, 57%), Camphor (24%, 24%) and Eucalyptol (13%, 13%) respectively. Main components L-Fenchone and Camphor caused about 100% mortality at 80 mu l/L dose in 48 hours. The results indicate that F. vulgare essential oil or its components may have a potential in controlling of A. obtectus.