A study on the correlation between sensitivity to diazinon and acetylcholinesterase enzyme activity in rice stem borer Chilo supressalis (Lepidoptera: Crambidae)
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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
Department of Plant Protection, Faculty of Crop Science, Sari Agricultural Sciences and Natural Resources University, Sari, Iran,
چکیده
In this study, the effect of diazinon insecticide was investigated on the activity of acetylcholinesterase enzyme (AChE) as an important factor in resistance of pests to pesticides in two populations of rice stem borer, Chilo supressalis. Eggs of the pest were collected from rice fields in Babol and Sari areas and reared in the laboratory up to the third-instar larvae. The bioassay test was performed on the third-instar larvae and the LC50 of diazinon was calculated as 4.12 and 4.64 ml/L for Babol and Sari populations, respectively, showing higher LC50 for Sari population in responding to diazinon, however, without any significant difference between 2 populations. Thereafter, the protein concentration in the larval extract was calculated between 50 and 70 mg/L. The activity of the AChE subjected to sublethal concentrations of diazinon ranged from 1.7992 to 0.1552 μmol/g FW and 2.0883 to 0.0749 μmol/g FW min, in Babol and Sari populations, respectively. Moreover, for both populations, the changes in enzyme activity were observed at 2 ml/L pesticide concentration. By increasing the concentration of pesticide, AChE activity tended to zero. As LC50 increased, the enzyme activity leveled up. Due to higher LC50 and AChE activity, Sari population of rice stem borer is considered more resistant to diazinon compared to Babol population. The results could be useful in management of the pest populations in the region.
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