The use of Sporothrix insectorum and Paecilomyces fumosoroseus against Boophilus microplus (Canestrini, 1887): in vitro assay and electronic microscopy

Abstract

In function of the development resistance to the several existent quimiotherapics, biological control has being a promising alternative to the control of Boophilus microplus. In this work, the pathogenic action of Sporothrix insectorum and Paecilomyces fumosoroseus in the different stages of life cycle of Boophilus microplus was evaluated. The fungis in study were cultivated in appropriate culture medium and suspensions in the concentrations of 105, 106, 107, 108, 109 conidia/mL for both fungis were prepared, starling from stock suspension. The eggs and the larvaes were treated by spray, and the engorged tick were immersed in the different conidia suspensions. The pathogenicity of the fungis were appraised for the reproductive performance of the ticks. The experimental was accomplished with five repetitions for each treatment group, in the different fungal concentrations. The fungis S. insectorum and P. fumosoroseus reduced in 50,19% and 49,34%, respectively, the posture of the infected engorged female ticks, in the concentration 108 conidia/mL. In relation to effectiveness, the fungis S. insectorum and P. fumosoroseus, they reached the values 82,99%, in the concentration 108 conidia/mL, and 82,93% in the concentration 109 conidia/mL, for the respective fungis. In the eggs treatment with the S. insectorum and P. fumosoroseus, the fungi P. fumosoroseus presented a superiority with reduction of eclodibility in 79,04%, in the concentration 106 conidia/mL, while the S. insectorum, reduced in only 37,92%, in the concentration 107 conidia/mL. In the larvas treatment there were not significant differences in the larva mortality in both fungi. The electronic microscopy, in different stage of life of the B. microplus, showed the power predatory of the fungi S. insectorum and P. fumosoroseus. With these results, it can be inferred that S. insectorum and P. fumosoroseus presented deleterious action on engorged female of B. microplus in vitro, what reinforces your possibility eventual control of this important tick.