In vitro evaluation of five ixodicides against Rhipicephalus microplus in Catacamas, Olancho, Honduras

Objective. The objective of the present investigation was to evaluate the in vitro efficacy against Rhipicephalus microplus of five commercial products used in the site with the highest production of cattle in Honduras. Materials and methods. Ticks were collected in four cattle farms in Catacamas (14° 50' N, 85° 53' S), considering a quantity of 300 bovines, obtaining approximately 1.000 teleogynes of R. microplus to form a control group with distilled water and five treatment groups, each group included two replicates with 50 individuals (n = 100). The adult immersion method was performed with each of the five commercial products and the following rates were estimated: mortality, oviposition, hatching, reproductive efficiency and product efficacy. Results. Four of the commercial products with the following active ingredients (Product 1: cypermethrin, chlorpyrifos, piperonyl butoxide. Product 2: cypermethrin, ethion, piperonyl butoxide. Product 3: amitraz. Product 4: coumaphos), showed an efficacy greater than 90%. On the other hand, a product (Product 5: cypermethrin), presented an efficiency of 68%. This product of the pyrethroid family shows efficacy problems with a mortality of 33% and a reproductive rate of 30%. Conclusions. One of the products evaluated (cypermethrin) showed low in vitro efficacy against R. microplus in Catacamas, Honduras. It is necessary to modify the use of cypermethrin in this locality, preventing possible problems of resistance to ixodicides.