SENSITIVITY OF BOOPHILUS MICROPLUS (ACARI: IXODIDAE) TO PYRETHROIDS AND ORGANOPHOSPHATE IN FARMS IN THE VALE DO PARAÍBA REGION, SÃO PAULO, BRAZIL

Abstract

ABSTRACT A study to evaluate the resistance of B. microplus to the active principles cypermethrin, deltamethrin and chlorpyriphos was performed together with the survey of the tick control practices used in 12 farms located in Vale do Paraíba Region, São Paulo, Brazil. Results obtained by the larval packet test (LPT) technique, adopted by FAO, showed established resistance to pyrethroids (cypermethrin 16.7% sensitive, 8.3% resistant level I and 75% resistant level II; deltamethrin 25% /sensitive, 33.3% resistant level II and 41.7% resistant level III) and emerging resistance to organophosphate compounds (chlorpiriphos 58.3% sensitive, 33.3% resistant level I and 8.4% resistant level II). The inquiry applied to the farmers showed that the combination of organophosphates and pyrethroids compounds products is the most commonly tick-killing compounds used in the region, followed by amitraz and macrocyclic lactones.