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Deltamethrin resistance in the sea louse C aligus rogercresseyi ( B oxhall and B ravo) in C hile: bioassay results and usage data for antiparasitic agents with references to N orwegian conditions
Author(s) -
Helgesen K O,
Bravo S,
Sevatdal S,
Mendoza J,
Horsberg T E
Publication year - 2014
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.12223
Subject(s) - deltamethrin , biology , bioassay , microbiology and biotechnology , chemistry , pesticide , genetics , ecology
The sea louse C aligus rogercresseyi is a major threat to C hilean salmonid farming. Pyrethroids have been used for anticaligus treatments since 2007, but have shown reduced effect, most likely due to resistance development. Pyrethroid resistance is also a known problem in L epeophtheirus salmonis in the N orthern H emisphere. This study describes the development of deltamethrin resistance in C . rogercresseyi based on bioassays and usage data for pyrethroids in C hilean aquaculture. These results were compared to bioassays from L . salmonis from Norway and to N orwegian usage data. Available deltamethrin bioassay results from 2007 and 2008, as well as bioassays from N orway, were collected and remodelled. Bioassays were performed on field‐collected sea lice in region X in C hile in 2012 and 2013. Bioassays from 2007 were performed prior to the introduction of pyrethroids to the C hilean market. Both the results from 2008 and 2012 showed an increased resistance. Increased pyrethroid resistance was also indicated by the increased use of pyrethroids in C hilean aquaculture compared with the production of salmonids. A similar trend was seen in the N orwegian usage data. The bioassay results from C hile from 2012 and 2013 also indicated a difference in the susceptibility to deltamethrin between male and female caligus.