CLORPIRIFOS AND CIPERMETRINA SENSIBILITY FOR TICKS Rhipicephalus microplus IN PANAMANIAN HERDS

Abstract

The objective of this study was to determine by the bioassay technique of Larval and Dosage Discriminants Package, the sensitivity to chlorpyrifos (organophosphate) and cypermethrin (synthetic pyrethroid) for the tick Rhipicephalus microplus on cattle farms of the Republic of Panama. The study was divided into two periods, 26 farms were sampled during the first period from November 2008 to December 2009, and it included the Tropical rainforest area of the sub-basins of los Hules, Tinajones and Caño Quebrado rivers, within the Panama Canal basin, the second period of study was from May 2010 to July 2012, where 25 farms were sampled; it included the dry forest and tropical rain forest in the provinces of Darien, Panama, Cocle, Herrera, Los Santos, Veraguas and Chiriqui. The results of the first period (2008-2009) showed an average mortality rate of ticks of 14,1% with cypermethrin, with a range from 1,36% to 47,22%, which is considered low to medium. Chlorpyrifos averaged 99,5% of mortality with a range of 97,5% to 100,00%, indicating high mortality sensitivity. In the second period (2010-2012) mortality rates of tick averaged 33,89% (range of 13,27% to 95,23%) with cipermetrina and for chlorpyrifos 99,13% (range of 96,58% to 100%) was obtained. It is concluded that the bioassay was validated under local laboratory and field conditions, and it achieved reliable results on cypermethrin and chlorpyrifos sensitivity for Rhipicephalus microplus ticks.