In vitro efficacy of <scp> <i>Quillaja saponaria</i> </scp> extracts on the infective life‐stage of ectoparasite <scp> <i>Caligus rogercresseyi</i> </scp>

The effect of two different commercial products Quillaja saponaria saponin extract on mortality the free-living copepodite stage sea-lice Caligus rogercresseyi were assessed in vitro. Parasites exposed for 24 hr to concentrations extracts and then observed until 30 non-Quillaja media. EC50 EC90 evaluated at hr. High mortalities copepodites obtained higher doses (500 ppm) both extracts. Higher using product with content (23.3% vs. 86.6%) (63.3% 93.3%) compared containing less saponins. In addition, increased even after removing suggesting a residual prolonged survival parasite. Our results indicated that parasite is sensitive saponins from Q. may be used control or prevent infestation C. salmonids Chile.