Rhipicephalus microplus is responsible for major economic losses in cattle ranching in Brazil, and the development of multiple acaricide resistance is a major concern to control this ectoparasite. To determine the resistance of R. microplus to acaricides in 26 ranches in the semi-arid region of Paraíba State, Brazil, larval assays were performed with cypermethrin, chlorpyriphos, amitraz, ivermectin and fipronil and resistance was observed in all locations. The frequency of populations resistant to cypermethrin, chlorpyriphos, amitraz and ivermectin was, respectively, 96 %, 72 %, 83 % and 92 % while none was resistant to fipronil. Resistance to one, two, three and four acaricides was recorded, respectively, in 4 %, 15 %, 31 % and 50 % of the farms. Errors in the control management of R. microplus determined the development of resistance to acaricides in all evaluated properties pointing towards development of new strategies for its control. In order to control multiple acaricide-resistant cattle tick populations in this area it is recommended to apply suppressive treatments with fipronil and/ or fluazuron.

Rhipicephalus microplus造成巴西牛群饲养的重大经济损失，而多重杀螨剂耐药性的发展是控制这种体外寄生虫的主要问题。为了确定巴西帕拉伊巴州半干旱地区的26个牧场中的R. microplus对杀螨剂的抗药性，使用氯氰菊酯，毒死py，阿米特拉斯，伊维菌素和氟虫腈对幼虫进行了幼虫试验，在所有位置均观察到了抗药性。对氯氰菊酯，毒死ri，阿米特拉斯和伊维菌素有抗药性的人群的频率分别为96％，72％，83％和92％，而对氟虫腈无抗药性的人群。在4％，15％，31％和50％的农场中分别记录了对一种，两种，三种和四种杀螨剂的抗性。控制管理中的错误R. microplus在所有评估的特性中都确定了对杀螨剂的抗性发展，这表明开发了新的控制策略。为了控制该地区的多个抗杀螨剂牛cattle种群，建议使用氟虫腈和/或氟嘧磺隆进行抑制性治疗。