Chemical composition and fumigant toxicity of essential oil from Thymus carmanicus against two stored product beetles

Abstract : Chemical composition of the essential oil from Thymus carmanicus Jalas, and its fumigant activity was investigated against two stored product insects, Callosobruchus maculatus (F.) and Sitophilus granarius (L.). Essential oil was isolated via hydrodistillation from dry leaves of T. carmanicus using a modified Clevenger-type apparatus and the chemical composition of the oil was assessed via GC and GC-MS. Twenty one compounds (100% of the total composition) were identified. Carvacrol (41.14%), p-cymene (12.09%), Thymol (6.35%) and γ-terpinene (6.21%) were found to be the major compounds of the essential oil. The fumigant toxicity of the essential oil was tested against 1-3 day-old adults of C. maculatus and S. granarius at 27±1ºC and 65±5% r.h. in darkness. The mortality of adults was tested at different concentrations (28.12, 40.62, 53.12 and 65.62 µl/l air ) and different exposure times. The highest concentration (65.62 µl/l air), caused 84% and 56% mortalities with a 5 h exposure On C. maculatus and S. granarius, respsctively. Based on LC50 values, C. maculatus (9.28 µl/l air) was significantly more susceptible than S. granarius (12.71 µl/l air). These results showed that the essential oil of T. carmanicus can play an important role in stored-product protection
Keyword : Fumigant toxicity, Essential oil, Thymus carmanicus, Callosobruchus maculatus, Sitophilus granarius
Author(s) : , A. Jarrahi, S. Moharramipour, S. Imani
Downloads : 1179

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