02145naa a2200229 a 450000100080000000500110000800800410001902400380006010000190009824501310011726000090024850002270025752011510048465300110163565300300164665300280167670000170170470000180172170000170173970000200175677301390177610610212021-08-10       2020    bl uuuu     u00u1 u    #d7 a10.1016/j.ttbdis.2020.1014132DOI1 aVILELA, V.L.R.  aMultiple acaricide-resistant Rhipicephalus microplus in the semi-arid region of Paraíba State, Brazil.h[electronic resource]  c2020  aArticle history: Received 18 August 2019; Received in revised form 22 January 2020; Accepted 8 March 2020. Corresponding author at: Avenida Presidente Tancredo Neves, s/n, Jardim Sorrilândia, 58800-970, Sousa, PB, Brazil.  aRhipicephalus 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.  © 2020 Elsevier GmbH  aBRASIL  aIN VITRO LARVAL BIOASSAYS  aRHIPICEPHALUS MICROPLUS1 aFEITOSA, T.F1 aBEZERRA, R.A.1 aKLAFKE, G.M.1 aRIET-CORREA, F.  tTicks and Tick-borne Diseases, July 2020, Volume 11, Issue 4, Article number 101413. Doi: https://doi.org/10.1016/j.ttbdis.2020.101413