تاثیر اسانس آویشن باغی و ترکیبات موثره آن بر لارو Glyphodes pyloalis (Lepidoptera: Crambidae)

The lesser mulberry snout moth, Glyphodes pyloalis (Walker 1859) (Lepidoptera: Crambidae), is one of the most important pests of mulberry trees in northern Iran, and its feeding on mulberry leaves can cause economic losses to farmers. The pest is also suspected in transmission of pebrin disease by feces. Thyme, Thymus vulgaris L., is a woody and perennial plant with insecticidal and repellent properties reported from some insects. In order to investigate the effect of thyme essential oil and its major compounds on mulberry snout moth larvae, they were collected and transferred to the laboratory of plant protection department at Guilan university. The colony of this pest was established at 26±2 °C, 60±5% relative humidity, 16 h of light and 8 h of darkness. The main constituents of thyme essential oil were analyzed by GC-MS which were thymol, P-cymene, linalool and carvacrol 26.92, 14.54, 13.39 and 5.68%, respectively. The LD50 values on 24 h 3rd instar larvae were estimated after 48 hours. These values were estimated 2.82, 32.18 and 56.54 μg per larvae for thyme essential oil, thymol and carvacrol respectively. Due to the role of detoxifying enzymes in reducing toxicity of used compounds, the activity of certain detoxifying enzymes such as α- and β-esterase, glutathione S-transferase and cytochrome P450 were studied. The results showed significant inhibition of these enzymes treated larvae compared to the control. Also, the activity of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatases enzymes in thymol-treated larvae decreased while the activity of acid phosphatases was increased. Our results suggest that thyme essential oil and its components have the potential in controlling G. pyloalis larvae in mulberry orchards.