1998 Volume 3 Issue 1 Pages 43-46
The acute toxicity levels of 5 kinds of fungicide against the free-living protozoal ciliate Colpoda aspera were tested in cocultivation with Alcaligenes faecalis IFO13111. The fungicides used were products containing the following effective components: dimethilimol (DMM), admixture of ziram, thiram and polyoxin (ZTP), flutolanil (FLN), streptomycin (SM), or 8- hydroxyquinoline copper and captan (CHC). Each fungicide was added at varying concentrations, and the effective concentration (EC50) at which the specific growth rate of C. aspera was reduced to 50% after 24 h culture was defined as the acute toxicity of the fungicide tested. It was found that ZTP had the highest level of toxicity, followed by CHC, SM, DMM and FLN. When the fungicides were evaluated in terms of safety on the basis of indices obtained by dividing normally applicable concentrations (NC) by EC50, the safety levels of SM, DMM and FLN were high compared to those of ZTP and CHC.
