CONICET | Buscador de Institutos y Recursos Humanos

Stochastic models are valuable tools to describe and analyze tick population dynamic in a given area, and toevaluate different control schemes. The objective of this study was to provide a tool to predict a priori how acontrol scheme could affect the abundance of Rhipicephalus microplus in an area highly favourable for itsdevelopment, through the building of a stochastic model of the population dynamic of this tick. The dynamic wasstochastically modelled using field data of the parasitic and non-parasitic phases of R. microplus. The host susceptibilityto tick infestations was also considered by including representative values of natural resistance ofthree different breeds (Bos indicus, B. taurus and B. indicus x B. taurus). Two different control schemes (strategicand threshold methods) using three annual applications of synthetic acaricides in different moments wereevaluated. Furthermore, we have evaluated the impact of different moments of pasture spelling as a tool for tickcontrol on the dynamic of the non-parasitic phases of R. microplus. The results showed that the model appropriatelyfits to field data and can simulate the annual variability in female ticks count in animals from differentecological characteristics. The model has also captured the variability that host susceptibility has on tickabundance. This fact was expressed in the different levels of tick abundance obtained for the three breeds ofbovines. According to the model, strategic control applications of chemical acaricides have more efficacy thanthe threshold control method. The model indicates that a pasture spelling started in early or mid-summer generatesa higher reduction in the number of available eggs in pastures. Analysis of the results allows to concludethat the model developed in this study was useful to predict a priori the performance of different control methodsbased on the strategic application of chemical acaricides or by applying pasture spelling.

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