[Efficiency of Beauveria bassiana and Metarhizium anisopliae formulations on Amblyomma cajennense (Fabricius, 1787) nymphae].

Amblyomma cajennense is a vector of several infectious diseases on mammals and became a serious problem in some localities in Brazil. Entomopathogenic fungi are very important biocontrol agents and could be a viable alternative for the control of this tick in permanent preserved areas. The aim of this study was to evaluated the mortality of tick nymphae treated with Beauveria bassiana and Metarhizium anisopliae formulations in laboratory conditions. Non fed nymphae were inoculated with 2x10(7) and 4x10(7) conidia/ml suspension of B. bassiana and 1x10(7), 1.5x10(7), 2x10(7), 3x10(7) and 5x10(7) conidia/ml suspension of M. anisopliae. Nymphae mortality found were 57.1 and 56.2% at the concentrations of 3x10(7) and 5x10(7) conidia/ml respectively, three days after treatment. After six days, the mortalities reached 100% for both highest concentrations and were between 25 and 35% for the others M. anisopliae treatments. The mortality caused by M. anisopliae at the concentrations of 1x10(7), 1.5x10(7) and 2x10(7) conidia/ml reached 60.6, 64.1 and 66.8% respectively, after ten days. B. bassiana formulation caused mortality only at the highest concentration. Oil formulation of M. anisopliae is an ecological option for tick control in areas where the use of chemical pesticides may cause undesirable impact.