Monitoring of Acaricide Resistance in Two-Spotted Spider Mite ( Tetranychus urticae) Populations from Rose Greenhouses in Korea

Abstract

Laboratory studies were conducted to determine the effects of six acaricides on the eight field populations of two spotted spider mite, Tetranychus urticae, collected from rose greenhouse. There were considerable differences in susceptibility depending on the acaricides treated and on the regions from which the population was collected. The local resistance ratios in the egg stage were lower than those of female adults. The population with a resistance ratio higher than 10 with respect to an acaricide was regarded as the resistant population to the acaricide. The resistant populations in female adult stage include ‘Buyo’ and ‘Chilgok’ populations to abamectin, ‘Buyo’ and ‘Gimhae’ populations to acequinocyl, ‘Buyo’ and ‘Jeju’ populations to bifenazate, and ‘Gimhae’ population to emamectin benzoate. All populations to milbemectin showed small susceptibilities variation (RR <10). The resistant populations in egg developmental stage include six populations except for ‘Koyang’ and ‘Gumi’ populations to abamectin, all populations to acequinocyl and etoxazole, seven populations except ‘Buyo’ population to bifenazate, seven populations except for ‘Gimhae’ population to emamectin benzoate, and ‘Jeju’, ‘Chilgok’ and ‘Gimhae’ populations to milbemectin. However, ‘Jincheon’ and ‘Buyo’ populations were more susceptible to both milbemectin and bifenazate than susceptible strain. The eggs and adults of all field populations showed low resistance to milbemectin among the acaricides tested