Efficacy of emamectin benzoate in controlling natural infestations of ectoparasites in economically important fish species of India

Abstract

Efficacy of in-feed administration of emamectin benzoate (EMB) was evaluated in commercial culture farms of Asian seabass (Lates calcarifer), grey mullet (Mugil cephalus), pearlspot (Etroplus suratensis), Indian major carp (Labeo rohita), goldfish (Carassius auratus) and koi carp (Cyprinus rubrofuscus) in different parts of India. Fish naturally infested with Caligus minimus, Argulus quadristriatus, Argulus siamensis, Lernanthropsis mugilii and Lernaea cyprinacea were administered medicated feed for 7–10 consecutive days (@ 50 μg kg−1 body weight day−1). Efficacy of the treatment was monitored by recording the parasitic intensity (PI). The study revealed PI was zero on head and gills within four days while parasites remained on trunk and fins till six days both in seabass and pearlspot. However, zero PI was achieved on 6th day on head and gills, and on 8th day on trunk and fins in seabass and Indian major carp. Treatment with EMB for seven days was effective against C. minimus, A. quadristriatus, A. siamensis and L. mugilii in E. suratensis, L. calcarifer, L. rohita and M. cephalus, respectively while L. cyprinacea infestation in seabass, goldfish and koi carp needed an extended treatment up to 10 days. In all the cases no recurrence was observed for 60 days post medication. Study revealed that there is a need for integrated pest management (IPM) program for effective prevention and control of parasitic infestation in commercially important food and ornamental fish cultures.