Acaricidal activity of cashew nut shell liquid associated with essential oils from Cordia verbenacea and Psidium guajava on Rhipicephalus microplus

The aim of this study was to assess theeffectiveness of cashew nut shell liquid (CNSL),Cordia verbenaceaandPsidium guajava, both alone and in associationagainstRhipicephalus microplus. Larval packet and adult immersion tests were conducted in concentrations ranging from 3.1 at 100.0mgmL(-1). CNSL was effective against engorged females (99.6%) at100.0mgmL(-1)and against larvae (99.2 %) at50.0mgmL(-1). The highest efficacy on engorged females was achieved by the essential oils ofP.guajavaat12.5mgmL(-1)(99.9%), followed by those ofC.verbenaceaat25.0mgmL(-1)(96.9%), while a low larvicidal activity of 5.8 and 59.0% was, respectively, obtained. The association at50.0mgmL(-1)had asignificant effect on both life stages ofR.microplus. This association caused considerable larval mortality (95.3%) and high efficacy on engorged females (93.9%).