Document Type : Research Paper
Author
عضو هیئت علمی
Abstract
Background and objectives: Considering the high damage caused by storage pests and the adverse effects of chemical pesticides, using plant compounds is considered one of the best options for controlling storage pests. Essential oils are an effective plant compound with a high fumigant effect. In this study, Oviposition deterrence and ovicidal activities of three native species of savory were investigated to select the savory essential oil with the highest insecticidal properties.
Methodology: First, three native species of savory (Satureja sahendica, Satureja khuzistanica, and Satureja macrantha) were collected, and essential oils were extracted after drying. All three essential oils were injected into a gas chromatograph and gas chromatograph coupled with a mass spectrometer to determine chemical compounds. Experiments were performed in a completely randomized design and were evaluated under laboratory conditions (27±1°C, 65±10 R.H. and 16:8 L:D).To determine the oviposition deterrence of the oils, one pair of one-day-old adult moths was exposed to different concentrations of the oils for four days, and the number of deposited eggs was counted. Also, one-day-old eggs were exposed to three oil concentrations at 3, 12, and 25 μl essential oil/l air. The percentage of egg hatching was recorded after 96 hours. The experiment was performed in 5 replications.
Results: The results showed that carvacrol content, as the principal active ingredient of S. khuzistanica, was 91.5%. Thymol (48.59%), p-cymene (59.5%) and γ-terpinene (18.57%) had the highest amount in the essential oil of S. sahendica, respectively. The dominant components of S. macranthaessential oil were p-cymene (59.5%), γ-terpinene and thymol (13.5%). All three essential oils had the Oviposition deterrent activity, and the rate of Oviposition deterrence increases with increasing concentration of essential oils. Different concentrations of three savory essential oils showed that at a concentration of one microliter with S. khuzistanica essential oil, more than 50% oviposition deterrent activity was observed. In comparison, oviposition deterrent activity was observed for two other savory essential oils at a concentration of 3 microliters. Among the investigated essential oils, S. khuzistanica had the highest effect of oviposition deterrent activity on Mediterranean flour moths. Also, there is a significant difference in the ovicidal activity of S. khuzistanica compared to the others, which can be attributed to its high carvacrol content. In contrast to the low insecticidal effect of the essential oil of S. macrantha, it has had a very suitable effect of oviposition deterrent activity.
Conclusion: All three types of savory essential oils had sound oviposition deterrence effects and ovicidal activity, but S. khuzistanicaessential oil in the lowest concentration had better oviposition deterrence effects and ovicidal activity than S. sahendica and S. macrantha, that it is also more acceptable from an economic point of view. Based on the results of this research, the essential oils of native Iranian savory spices can control storage pests; only high volatility and insolubility in water are the main limitations in the widespread use of essential oils. However, the nanoencapsuled essential oil, through the controlled release of active ingredients, overcomes the restrictions of plant essential oil usage in storage. Therefore, more studies are needed to use essential oils in pest control using this method
Keywords
- Satureja khuzistanica Jamzad
- Satureja sahendica Bornm
- Satureja macrantha C. A. Mey
- Mediterranean flour moth
- Oviposition deterrence
- ovicidal activity
Main Subjects
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