بررسی سمیت اسانس آویشن و ترکیبات موثره آن بر فعالیت آنزیم های گوارشی و مراحل زیستی Glyphodes pyloalis Walker (Lepidoptera: Crambidae)

Due to the harmful side effects of chemical insecticides, the use of compounds of plant origin has been considered today. The mulberry pyralid moth, Glyphodes pyloais Walker (Lepidoptera: Crambidae), is an important pest of mulberry orchards in the northern regions of the country. In the present study, the oral toxicity of thyme essential oil (EO), Thymus vulgaris L., and two compounds thymol and carvacrol, in an incubator set at a temperature of 26 ± 1 ºC, relative humidity of 60 ± 5 percent and a photoperiod of 16 hours of light and 8 hours of darkness on this pest (age third 24 hours) was evaluated. Investigating the activity of digestive enzymes of mulberry pyralid moth larvae that were fed on concentrations of 0.125 and 0.5% of thyme EO and thymol and carvacrol compounds, shows a significant difference between control and treatments. The activity levels of alpha-amylase, alpha-glucosidase, total protease, and serine proteases (trypsin, chymotrypsin, and elastase) in larvae treated with the above compounds decreased compared to the control and the activity of beta-glucosidase showed a significant increase compared to the control. Aminopeptidase enzyme activity in larvae treated with 0.5% thyme EO and 0.5% thymol shows a significant decrease compared to the control. Also, the activity of carboxypeptidase enzyme was significantly increased in thyme treatment by 0.5% compared to control and other treatments. To investigate the biological stages, 100 repetitions were considered for each treatment, but due to the toxicity of the compounds on the above pest, they could not complete their growth process. The highest percentage of losses was calculated in thyme EO 55%, thymol 47%, and carvacrol 22% respectively. On the other hand, the examination of the results related to the length of the larval, pre-pupal, and pupal periods showed that, in general, after the treatment of mulberry leaf-eating moth larvae with a concentration of 0.125% of thyme EO and thymol and carvacrol compounds, there was a significant increase compared to the control treatment. According to the above results, it can be concluded that thyme EO, thymol and carvacrol compounds can be used to control this pest due to their good control effects on the berry leaf-eating moth.