Azadeh Jarrahi - Department of Entomology, Faculty of Agriculture, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Saeid Moharramipour - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Sohrab Imani - Department of Entomology, Faculty of Agriculture, Science and Research Branch, Islamic Azad University, Tehran, Iran.

Plant essential oils and their constituents are recognized as proper alternatives to fumigants. Thymus daenensis Celak is one of these plants that have medicinal properties and is endemic to Iran. The essential oil was isolated by hydrodistillation from dry leaves using a modified clevenger-type apparatus and the chemical composition of the oil was assessed via GC and GC-MS. Fourteen compounds (۱۰۰% of the total composition) were identified. Thymol (۵۷.۴%), carvacrol (۹.۸%), β-caryophyllene (۶.۹%), γ-terpinene (۶.۷%) and p-cymene (۶.۳%) were found to be the major compounds of the essential oil. The fumigant toxicity of the essential oil was tested against ۱-۳ days old adults of Callosobruchus maculatus (F.) and Sitophilus granarius (L.) at ۲۷ ± ۱ °C and ۶۵ ± ۵% R. H. in darkness. The mortality of adults was tested at different concentrations (۲۸.۱۲, ۴۰.۶۲, ۵۳.۱۲ and ۶۵.۶۲ µl/l air) and different exposure times. At the highest concentration (۶۵.۶۲ µl/l air), T. daenensis oil caused ۹۰ and ۶۰% mortality with a ۳ h exposure on C. maculatus and S. granarius, respectively. Based on LC۵۰ values, C. maculatus (۴.۲۲ µl/l air) was significantly more susceptible than S. granarius (۶.۵۵ µl/l air). These results show the efficacy of T. daenensis oil for stored-products protection.

fumigant toxicity, Essential oil, Thymus daenensis, Callosobruchus maculatus, Sitophilus granarius