| Autor: |
Machado FA; Laboratório de Doenças Parasitárias, Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria ? UFSM, Santa Maria, RS, Brasil., Pivoto FL; Clínica de Medicina de Ruminantes, Departamento de Clínica de Grandes Animais, Universidade Federal de Santa Maria ? UFSM, Santa Maria, RS, Brasil., Ferreira MS; Laboratório de Doenças Parasitárias, Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria ? UFSM, Santa Maria, RS, Brasil., Gregorio Fde V; Santa Maria, Santa Maria, RS, Brasil., Vogel FS; Laboratório de Doenças Parasitárias, Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria ? UFSM, Santa Maria, RS, Brasil., Sangioni LA; Laboratório de Doenças Parasitárias, Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria ? UFSM, Santa Maria, RS, Brasil. |
| Abstrakt: |
The aim of the present study was to assess the acaricide resistance of tick populations in the western-central region of Rio Grande do Sul (Brazil), which has not previously been reported. Fifty-four cattle farms were visited and specimens of Rhipicephalus (Boophilus) microplus were collected and subjected to the adult immersion test, using nine commercial acaricides in the amidine, pyrethroid and organophosphate groups. Climatic data, including monthly precipitation, were recorded. The results from the present study demonstrated that seven of the acaricides analyzed presented mean efficacy values of less than 95%, with large differences among the products tested. Nine of them exhibited satisfactory and unsatisfactory acaricide results on at least one farm. In conclusion, the farms located in the western-central region of Rio Grande do Sul, Brazil, exhibited populations of R. (Boophilus) microplus with variable degrees of susceptibility to different acaricides, thus suggesting that resistance to the active compounds exists. It is suggested that treatment protocols should be implemented at the beginning of winter and summer, using the acaricides that showed efficacy in the adult immersion test. |
