Efficacy of commercial synthetic pyrethroids and organophosphates associations used to control Rhipicephalus (Boophilus) microplus in Southern Brazil

Caroline Zamperete Reginato, Gustavo Cauduro Cadore, Fernanda Rezer de Menezes, Luis Antonio Sangioni, Fernanda Silveira Flores Vogel
2017 Revista Brasileira de Parasitologia Veterinária  
This study evaluated the acaricidal efficiency of synthetic pyrethroids (SP) associated with organophosphates (OP) against Rhipicephalus (Boophilus) microplus populations in the state of Rio Grande do Sul, Southern Brazil. Ticks were collected in 54 cattle farms and tested using in vitro adult immersion test against four commercially available acaricide mixtures of SP and OP. Only one of four acaricides, comprising a mixture of cypermethrin, chlorpyrifos, and fenthion, had a mean efficiency
more » ... er than 95%, and was effective in 94.44% (51/54) of the cattle farms tested. The acaricide with a mixture of cypermethrin, chlorpyrifos, and citronelall had the lowest mean efficiency (62.11%), and was effective in 29.62% (16/54) of cattle farms tested. Furthermore, R. (B.) microplus in Southern Brazil exhibited differing degrees of resistance to SP and OP mixtures. The results suggest that the presence of fenthion contributes to the higher efficiency of the formulation with this active principle. This is possibly due to its recent commercial availability, as tick populations have been lower challenged with this product. Monitoring the resistance of ticks to carrapaticides is essential to maximize the efficiency of these products in the control of R. (B.) microplus.
doi:10.1590/s1984-29612017054 pmid:29091122 fatcat:scj6ivcs5za7phjkzz5rzpq4re