The Efficacy of Geraniol and ß-Citronellol against Freshwater and Marine Monogeneans.

Abstract

Monogeneans are parasitic flatworms that may be a threat for finfish aquaculture. In this study, the anthelmintic activity of two terpenes, geraniol and β-citronellol, was tested in vitro against ancyrocephalin and diplectanid monogeneans. Experiments were performed in both water and a culture medium. We observed that monogeneans in culture medium may be more tolerant to treatments compared with bioassays performed only in water. Concentrations of 300mg/L of both compounds were required to kill 100% of monogeneans at 1h postexposure. The toxicity of β-citronellol to fish was not evaluated. However, geraniol at 300mg/L and 150mg/L killed juvenile Nile Tilapia Oreochromis niloticus and White Snook Centropomus viridis, respectively, after a few minutes. Therefore, the present work suggests that other alternatives should be studied for use against monogeneans in aquaculture.