In vitro Efficacy of Verticillium lecanii and Beauveria bassiana of Commercial Source Against Cattle Tick, Rhipicephalus (Boophilus) annulatus

Two entomopathogenic fungi, Verticillium lecanii and Beauveria bassiana, were tested against Rhipicephalusannulatus. Mycotal® was the source of Verticillium lecanii while Biosect® was the source of Beauveria bassiana. Five concentrations (1×107, 5×108, 2.5×109, 1×1010 and 4×1010 spore/ml) of Verticillium lecanii as well as five different concentrations (5×107, 2×108, 8×109, 3.2×1010 and 12.8x1010/ml) of Beauveria bassiana were prepared and tested against adult female tick, eggs and larvae. The mortality in adult ticks was 60.60 to 72.00% after 2 weeks of application for V. lecanii at concentration ≥ 5x108spore/ml, while B. bassiana showed no mortality at any concentrations. The treated tick revealed nutritional index significantly lower than control untreated one for both fungi. Furthermore, V. lecanii showed no effect on eggs, while, B. bassiana delayed and reduced the egg hatching. In addition, both fungi caused 100% mortality of larvae. The effective concentration was ≥ 108spore/ml for both fungi with no significant difference among the highest concentrations. Moreover, the fungal extract had no effect on adult tick. In conclusion, V. lecanii is lethal to adult tick and B. bassiana caused larvae mortality and reduced egg hatching. A prospective application of fungi of commercial source in the pasture or animal farm is possible for tick control.