Comparative effects of various antibiotics, fungicides and disinfectants on Aphanomyces invaderis and other saprolegniaceous fungi.
A total of 54 isolates of various fish-pathogenic and saprophytic fungi were characterized in terms of their susceptibility to 3 antibiotics (penicillin, streptomycin and oxolinic acid), 3 fungicides (malachite green, hydrogen peroxide and sodium chloride) and 3 disinfectants (an iodophore, sodium hypochlorite and a solution of peracetic acid and hydrogen peroxide). A. invaderis, the fungus associated with the Asian fish disease epizootic ulcerative syndrome (EUS); other Aphanomyces sp. isolates from the similar conditions redspot disease (RSD) and mycotic granulomatosis (MG); and the crayfish plague fungus, A. astaci, were more sensitive to most of the chemical agents than the other fungi tested (Achlya and Saprolegnia spp.). Two compounds currently being considered for use in aquaculture, hydrogen peroxide and Proxitane 0510, were shown to have some potential for fungicidal treatments and disinfection, respectively. The implications of this study with respect to the isolation, treatment and control of A. invaderis are discussed.