Repellency Effect of Three Herbal Essential Oils on the Two--spotted Spider Mite, Tetranychus urticae

Two-spotted spider mite (Tetranychus urticae Koch)، is one of the most seriously important polyphagous pests that causes considerable damage to agricultural crops. In recent years، due to problems associated with the use of synthetic pesticides، herbal essential oils have received due attention as natural plant pest control compounds. In the present study، repellency effect of herbal plant essential oils extracted from some Lamiaceae family members namely: rosemary (Rosmarinus officinalis L.)، savory (Satureja hortensis L.)، and peppermint (Mentha piperita L (. were studied on T. urticae employing Twin Towers Bioassay (TTB) method. The experiments were conducted at 23±2°C، 60±5% relative humidity and fully light photoperiodism. Bioassay experiments were carried out at 0. 043، 0. 073، 0. 326 and 0. 348 µL/cm2 doses of the essential oils within four experimental intervals of time. The results indicated that peppermint essential oil had the most repellent effect (91%) on female adults of T. urticae at highest dose (0. 348 µL/cm2)، but there was no significant difference observed between peppermint oil and the oils extracted from other herbal plant. (P> 0. 05). In addition، the most persistency was observed for savory essential oil. Throughout the study، a new method was also introduced to evaluate the repellency effect of essential oils on some such herbivorous arthropods as mites.