Repellent, toxic and reproduction inhibitory effects of essential oil vapours on Acanthoscelides obtectus (Say) (Coleoptera : Bruchidae)

Thirteen essential oils (Apium graveolens, Citrus sinensis, Eucalyptus globulus, Juniperus oxycedrus, Laurus nobilis, Lavandula hybrida, Mentha microphylla, Mentha viridis, Ocimum basilicum, Origanum vulgare, Pistacia terebinthus, Rosmarinus officinalis, and Thuja orientalis) were tested in their vapour form against Acanthoscelides obtectus. Choice and no-choice tests revealed that most of them have a repellent action, reduce fecundity, decrease egg hatchability, increase neonate larval mortality and adversely influence offspring emergence. Furthermore, some oils were strongly toxic to A. obtectus, males appearing more susceptible than females. Among the essential oils tested, the most toxic for males were those of M. microphylla and M. viridis whereas the most toxic against females were those of L. hybrida and R. officinalis. (C) 2001 Elsevier Science Ltd. All rights reserved.