In vitro treatments of deltamethrin against the isopod parasite Ceratothoaoestroides, a pathogen of seabass Dicentrarchus labrax L.

The ill vitro, efficacy of the pyrethroid deltamethrin against the isopod p arasite Ceratothoa oestroides was determined under laboratory conditions. T he following concentrations of the drug were tested on adult and pre-adult parasites by means of bath treatments of half an hour duration: 10mg/L, 1mg /L, 3mg/L, 0.3mg/L, 0.1mg/L, 0.01mg/L, 0.05mg/L, 10 mug/L, 5 mug/L, 0.15 mu g/L, 0.1 mug/L. Results were assessed after 30 minutes, 2, 12, 24 and 48 hr s. The best concentration was proved to be 0.05mg/L where all parasites die d at 2 hours and remained dead for 48 hrs.