Abstract

The two-spotted spider mite, Tetranychus urticae Koch, is a polyphagous pest that causes considerable damage to field, horticultural and greenhouse crops. Currently, many plant essential oils and their active compounds have received attention because of their lethal effect against arthropod pests such as herbivorous mites. In this study, contact toxicity of three formulated compositions based on synthetic thymol and menthol including menthol 5%, thymol 5%, and a mixture of menthol 5% + thymol 5% tested against eggs and female adults of T. urticae. Adulticidal results showed that menthol 5% + thymol 5% had the lowest LC50 value (656.77 µl/l) 24 hours after the treatment. Likewise, the mixture was highly effective against T. urticae eggs and had the lowest LC50 value (967.24 µl/l). Although, the LC50 value of menthol 5% and menthol 5% + thymol 5% were not significantly different from each other but both of them had a significant difference with the thymol 5% in manner of adulticide and ovicidal. Results also showed that a combination of thymol and menthol increased lethal effects compared to these two compounds.