Selection for pyridaben, avermectin and abamectin+pyridaben resistance in Tetranychus truncatus Ehara
Author of the article:SONG Li-Wen** LI Miao-Wen SHEN Hui-Min***
Author's Workplace:Pratacultural College, Gansu Agricultural University, Key Laboratory of Grassland Ecosystem, Ministy of Education, The Sino-U.S. Centers for Grazingland Ecosystem Sustainability Lanzhou 730070, China
Key Words:Tetranychus truncatus (Ehara), pyridaben, avermectin, abameetin+pyridaben, resistance
Abstract:
[Objectives] To clarify the development of pesticide resistance, and the stability of resistance, to pyridaben, avermectin and avermectin+pyridaben in Tetranychus truncatus Ehara. [Methods] Biological assays were carried out in a laboratory to detect selection for resistance to pyridaben, avermectin, and avermectin+pyridaben, in T. truncatus, and the decline and recovery of resistance to these acaricides. [Results] After 30 generations of selection for resistance to the three acaricides, the resistance index to each increased by 197.50,19.56 and 12.57 folds, respectively. The resistance of a pyridaben resistant strain decreased very quickly in the absence of exposure to this acaricide, declining by 63.54% after 30 generations, whereas the resistance of avermectin resistant strain declined by 23.30% over the same number of generations. Resistance increased quickly after exposure to acaricides for about 30 generations. Resistance of the pyridaben resistant strain rapidly increased by 58.47%, but the recovery rate of the avermectin resistant strain was only 22.86%. The recovery rate of an abameetin+pyridaben resistant strain was intermediate; 38.67%. [Conclusion] The resistance of T. truncatus to pyridaben was relatively unstable and sensitivity to this acaricide returned relatively quickly. Resistance to avermectin and abameetin+ pyridaben were more stable, and sensitivity to these acaricides was difficult to reestablish. Consequently, avermectin should be used in rotation with the other insecticides to avoid cross-resistance and reduce selection pressure, thereby slowing the development of resistance in T. truncatus.