Toxicities of Four Pesticides and Effect on Acetylcholine Esterase Activity in Myzus persicae on Potato
CHANG Jing;ZHANG Wei;LI Hai-ping;ZHOU Xiao-rong;College of Agronomy,Inner Mongolia Agricultural University;
[Aims] The objective of this study is to survey the resistance level of peach aphid Myzus persicae(Sulzer) of Hohhot and Wuchuan area and to explore the mechanisms of the resistance. [Methods] Bioassay of frequently used four pesticides to two field populations of M. persicae in Hohhot and Wuchuan area and a sensitive population of M. persicae in Beijing area was conducted, and the acetylcholinesterase activities of this pest were tested as well. [Results] The results showed that the resistance ratios of two populations in Hohhot and Wuchuan area developed the medium to high resistance level to chlorpyrifos(25.79 and 70.20, respectively). And developed low-level resistance to omethoate, resistance ratios less than 5 compared with sensitive of Beijing area. Resistance retios(RR) were 3.86-6.88 folds respectively to methomyl and isoprocarb. There was a negative correlation between acetylcholinesterase activity and resistance ratio of chlorpyrifos.Three population were significantly inhibited by chlorpyrifos. [Conclusions] Acetylcholine esterase target insensitivity already develped in M. persicae of Hohhot and Wuchuan area, and suggested to choose other types of pesticides or mixture of insecticides.