Mortalities induced by entomopathogenic fungus Metarhizium anisopliae to different ticks of economic importance using two formulations

Abstract

The objective of this study was to compare the infe ctivity of Metarhizium anisopliae at a concentration of 1 × 10 8 conidia/ml to developmental stages of Amblyomma variegatum, Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi in oil and water formulations. The fungus, M. anisopliae, induced 50-100% mortalities in all developmental s tages of the tick species tested. R. e. evertsi was more susceptible to M. anisopliae than the other two tick species. However, there was no clear difference in mortality between fed and unfed instars of different tick species. Furthermore, engorged adults were more susceptible than unfed adult ticks. Oil formulated conidia induced significantly higher mortalities (P<0.05) t han water formulated conidia. The results indicate that the type of conidia formulation is critical to the performance of fungi as biological control age nts for ticks.