Bioecologia de Haematobia irritans L. (Diptera: muscidae) no sertão da Paraíba e caracterização do controle químico de ectoparasiticidas em bovinos no Brasil.

Abstract

This thesis includes two articles on the population dynamics of Haematobia irrtans in the Paraíba sertão and another article on the current panorama of the chemical control of horn flies and cattle tick in cattle herds of Rio Grande Do Sul, RS and Paraíba , PB, Brazil. The first chapter aimed to know the population dynamics and determine the levels of H. irritans infestation in the Paraíba semi-arid region, aiming to subsidize control programs. Horn fly infestations occurred throughout the study period with maximum individual infestations of 500 flies in cows and 1,800 flies on the bull. Influenced by the microclimatic influence of large reservoirs, the horn fly had a bimodal behavior, with annual population peaks in October /November and March. In the second chapter the frequency of susceptible and resistant H. irritans animals was estimated. At each count, the animals were individually classified into "susceptible" (high infestations) or "resistant" (low infestations), using two methodologies. Seven (7%) of the animals in the herd were classified as "susceptible" and 27% as "resistant". In the third chapter a study was carried out to evaluate the current panorama of H. irritans and R. microplus control in livestock farms in the state of Paraíba, PB and Rio Grande do Sul, RS. In the state of Rio Grande do Sul, 48.4% of the properties used commercial products containing active principles of the organophosphorus class, and in Paraíba (60.0%) they used pyrethroids to control the fly. Tick control was a common practice in 94.4% of the properties of Rio Grande do Sul and 47.2% in Paraíba, with up to 7 different insecticidal classes being used for their control. It is concluded that the number of flies found suggests important economic losses for cattle raising in the region and suggests the adoption of control measures in order to avoid infestation peaks and reduce economic losses. The control of the horn fly and cattle tick in properties of Paraíba and Rio Grande do Sul is carried out indiscriminately and without technical criteria. The current scenario constitutes a significant threat to Brazilian breeders of in the country cattle ranching.