Avaliação da compatibilidade dos fungos Entomopatógenos beauveria bassiana e metarhizium anisopliae expostos a carrapaticidas sintéticos

Abstract

One of the major problems in the national livestock scenario is the Rhipicephalus (Boophilus) microplus cattle tick, which was introduced through centuries of cattle use in exploratory expeditions in the Americas. Nowadays, losses caused by its presence are around US $ 3.4 billion annually, caused by the effect of parasitism on the animal, such as stress, weight loss, damage to the skin, transmission of pathogens and, especially, expenditures incurred in attempts to control the parasite. Control using chemicals is the main form of treatment today. However, its indiscriminate use may result in the emergence of resistance in the tick population. Therefore, to overcome this problem, biological control techniques have been gaining more space in the field, combined with chemical control, for greater effectiveness. However, synthetic products used in conjunction with biological control may, without due study, negatively affect the action of the organisms used in the integrated management, making synergistic use impracticable. Therefore, the objective of this work was to investigate whether acaricides used in the chemical control of ticks have a toxic effect on the entomopagenic fungi Beauveria bassiana and Metarhizium anisopliae. Using microbiology techniques, inoculants of M. anisopliae E6 strain and B. bassiana strains SG01, B03 and B06 were cultured in culture media mixed with commercial chemicals of different formulations from each other, called in the tests of Formulation 1 (active ingredient fluazuron), Formulation 2 (active ingredient cypermethrin), Formulations 3 and 4 (active ingredient chlorpyrifos) and Formulation 5 (active ingredient fipronil). Each containing a different active principle to be tested and with similar sales records. The results show the compatibility of four of the five products tested, with Formulation 1 being the only one incompatible for integrated pest management. Through the data obtained it is possible to elaborate future plans of integrated management in the populations of ticks resistant to the isolated chemical that are distributed by the country.