Control Strategies for the Tick Rhipicephalus Microplus (canestrini, 1888) on Cattle: Economic Evaluation and Report of a Multidrug-Resistant Strain

The aim of this study was to evaluate four strategies for application of acaricides to control the tick Rhipicephalus microplus among infested cattle, and to show which of these has the best cost–benefit ratio. For this, 72 cattle were selected and divided into four groups: Group 1 (G1): fipronil, pour-on; Group 2 (G2): fluazuron, pour-on; Group 3 (G3): moxidectin, injectable; and Group 4 (G4): chlorpyrifos 30 g, cypermethrin 15 g and fenthion 15 g, spraying (atomizing chamber). Every seven days, the numbers of semi-engorged females were counted and laboratory tests were conducted using different commercial technical-grade products for resistance monitoring. G4 showed the best percentage reduction, with the highest rate on the seventh day post-treatment (DPT) (83.23