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Abstract
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Attentive to defects of using chemical insecticides, in an attempt to find a natural method for the control of stored-product pests, fumigant toxicity of five medicinal plant essential oils including Eucalyptus globulus Labill., Salvia mirzayanii Rech. var. Hormoz., Ducrosia anethifolia Boiss., Zataria multiflora Boiss. var. Hormoz. and Majorana hortensis Moench was investigated against fourth instar larvae and adults of Carpophilus hemipterus (Linnaeus). For this purpose, essential oils were obtained using hydro distillation by a modified Clevenger-type apparatus. Fumigant toxicity was assessed at 25±1°C, 65±5% RH and under dark conditions. Mortality was evaluated at different concentrations ranging from 133.33 to 66.666 ?L/L air for larvae and 5 concentrations ranged from 13.33 to 666.66 ?L/L air for adults at 24, 48 and 72 hour exposure time and with 3 replications. In each of the containers 10 larvae or adults were released and the desired essential oil was released on the filter paper in the inner surface of containers at different concentrations. The results showed that by increasing concentration and time, mortality rate was increased. At the highest concentration, E. globulus, S. mirzayanii, D. anethifolia, Z. multiflora and M. hortensis essential oils resulted in 38, 63.3, 17.1, 52.8 and 35.3 percentage mortality of adults, and 52.2, 66.3, 52.2, 64.8 and 53 percentage mortality of larvae, respectively. Based on the fumigant toxicity of the studied essential oils, they can be used as a new and safe method to control this stored-grain insect pest.
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