تاثیر اسانس آویشن و ترکیبات تیمول و کارواکرول بر فعالیت سامانه ایمنی و آنتی اکسیدانی شب‌پره برگ‌خوار توت

The immune system and the activity of antioxidant enzymes in insects play an important role in detoxifying unpleasant compounds. In fact, different degrees of sensitivity to insecticide compounds can be due to biochemical differences in the detoxification of these compounds. In the present study, the effect of thyme essential oil (EO) and two compounds thymol and carvacrol on the immune system activity and the activity level of antioxidant enzymes of the mulberry pyralid moth, Glyphodes pyloalis Walker (Lepidoptera: Crambidae) was evaluated. To investigate the effect of thyme EO and thymol and carvacrol compounds, the larvae of this pest were collected from mulberry trees in Rasht City and transferred to the laboratory of the plant protection department of 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 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 EO, thymol and carvacrol respectively. Examining the results of immune system data showed that thyme EO and thymol compound can disrupt the function of this system in the treated larvae of the G.pyloalis. The results showed that the total number of hemocytes and on the other hand the percentage of plasmatocytes showed a significant decrease 24 and 48 hours after treatment in all concentrations of thyme EO and thymol compared to the control. . Also, the lowest number of granulocytes was observed after 24 hours in the thyme EO treatment compared to the control. The amount of phenoloxidase enzyme activity in larvae treated with thyme EO and thymol showed a significant decrease after 24 hours compared to the control. On the other hand, the number of nodules formed after the injection of B. bassiana with a dose of 104 decreased over time in all treatments, and the lowest nodule formation was observed in the larvae treated with thyme EO. Examining the results of the data of antioxidant enzymes showed that, in general, the activity of this enzyme group increased after treatment with thyme EO, thymol and carvacrol compared to the control. The comparison of average data at the 5% indicated that the activity of superoxide dismutase, catalase, and peroxidase enzymes in the treatments of thyme EO and thymol compound increased significantly compared to the control. The present results indicate that thyme essential oil or its effective compounds have the potential to inhibit G. pyloalis larvae and these compounds can be used as biological pesticides.