Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) HP88 for biological control of Rhipicephalus microplus (Acari: Ixodidae): The effect of different exposure times of engorged females to the nematodes

AbstractThe aim of this study was to assess the influence of different exposure times of engorged female the Rhipicephalus microplus to infective juveniles of Heterorhabditis bacteriophora isolate HP88. The engorged females were divided into seven groups (six treatments and one control) of 20 ticks each with statistically similar average weights (p>0.05) and exposed to concentrations of 300 nematodes/tick for periods of 3, 6, 12, 24, 48 and 72h. The following biological parameters were monitored: pre-oviposition period; egg mass weight; hatching percentage; and efficacy of treatment. There was no influence of the exposure time on the pre-oviposition period (p>0.05), while there were significant differences (p