The comparative repellency of ten selected native essential and edible oils was assessed against adults of S. granarius. The oils used are black seed oil (Nigella sativa), Sesame oil (Sesamum indicum), olive oil (Olea europaea), Peppermint oil (Mentha piperita), Basil oil (Ocimum basilicum), orange oil (Citrus sinensis), Rosemary oil (Rosmarinus officinalis), love oil (Dianthus caryophyllus), Garlic oil (Allium sativum), and Cinnamon oil (Cinnamomum zeylanicum). The repellent activity of different concentrations of each oil was investigated using the area preference method. All essential oils used showed much higher repellent activity to this insect than edible oils. The used oils can be arranged in descending order according to their average mean repellent
activity as follows: Cinnamon (96.19%), Garlic (91.27%), Clove (90.43%), Basil (87.04%), Peppermint (79.31%), Rosemary (74.49%),Orange peel (53.54%), Sesame (13.08%), Black seed (11.18%), whereas, Olive oil which was attractive to the insects (- 4.49%). In spite of Orange peel oil, no direct logarithmic correlation was found between the
repellent activity of oils and doses used. Also, results showed that the repellent activity of oils fluctuated between decrease and increase as the time of exposure increased. The possibility of using oils as repellents for stored product pests was discussed. |
