Pulses including cowpea, (Vigna unguiculata) are the important sources of protein in many developing countries. A key pest of cowpea is the cowpea seed beetle, Callosobruchus maculatus (F.), a bruchid that infests both pods in the field and seeds in storage. In the present study, the toxicity of vapours of the essential oils extracted from the flowers of the Lavender plant (Lavandula angustifolia Mill) and the shoots of Avishan Shirazi (Zataria multiflora Bioss) were investigated on both sexes of C. maculatus. Both essential oils showed high activity against one-2 day-old adults, depending on concentration and exposure time from 3 to 24 h. The oil of L. angustifolia was more effective than that of Z. multiflora on both sexes. The 24 h LC50 values of L. angustifolia oil were 33.91 and 53.57 µlL-1, while the corresponding values of Z. multiflora oil were 329.04 and 561.91 µlL-1 for males and females, respectively. The results suggested that the oils of these species can be employed as the potential alternatives to synthetic insecticides against the cowpea seed beetle. However, more investigations need to be done on the biological activity of the essential oils on other developmental stages.

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