From the laboratory to the field: efficacy of entomopathogenic nematodes to control the cattle tick.

Background: The control of ticks is challenged by the resistance of tick populations to chemical acaricides. In this study, we evaluated, under laboratory conditions, the efficacy of Heterorhabditis bacteriophora against Rhipicephalus (Boophilus) microplus engorged females with varying body weights (150, 200, 250, 300 or 350 mg per female) or from eight different geographical populations. We also determined the efficacy of H.