Submitted to: Pesticide Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 1999
Publication Date: N/A
Interpretive Summary: Studies were performed in the laboratory to determine several conditions and factors that might enhance the ability of the natural compound ferulate to inhibit the growth of the musty-odor producing cyanobacterium (blue-green alga) Oscillatoria cf. chalybea. O. cf. chalybea is the leading cause of musty off-flavor in farm-raised catfish from the Mississippi Delta. These studies identified the form of ferulate that is most toxic towards O. cf. chalybea in the laboratory and also found that light enhanced the toxicity of ferulate toward O. cf. chalybea in the laboratory. A better idea of the amount of ferulate to use in field (pond) studies was determined. These studies provided information that could be useful when testing ferulate in catfish production ponds for the control of O. cf. chalybea.
Technical Abstract: The objectives of this study were to determine the effect of ferulate and its analogs and factors which may effect the stability of ferulate on the growth of Oscillatoria cf. chalybea, the cyanobacterium attributed to causing musty flavor in farm-raised catfish. Rapid bioassays utilizing 96-well and 6-well cell culture plates were used to monitor the toxicity of ferulate analogs and potential ferulate-stability factors toward O. cf. chalybea. The additions of low concentrations of the oxidizing compound sodium carbonate peroxyhydrate with ferulate did not help control O. cf. chalybea. Of three forms of ferulate tested, trans-ferulate is most toxic towards O. cf. chalybea. Light enhanced the toxicity of ferulate indicating that weather conditions and the time of day could influence the successfulness of ferulate applications to fish ponds to control O. cf. chalybea. Ferulate was less toxic to O. cf. chalybea in 6-well culture plates than in 96-well plates, indicating that higher concentrations of ferulate should be used in field trials due to possible reduction of ferulate toxicity towards O. cf. chalybea in large, aquatic environments (i.e., fish ponds). These studies provided fundamental information on potential ferulate toxicity towards O. cf. chalybea to be considered before conducting field trials (ferulate applications to fish ponds).