INHIBITION OF PRODUCTION OF CYCLOPIAZONIC ACID AND OCHRATOXIN-A BY THE FUNGICIDE IPRODIONE

Aspergillus flavus NRRL 1290 and Aspergillus ochraceus NRRL 3174 were grown on a glucose-salts medium and yeast extract-sucrose broth contai ning the fungicide iprodione at concentrations of 0, 1, 3, 5, 10, 15, and 20 mu g of active ingredient per ml of growth medium. Cultures wer e analyzed for cyclopiazonic acid, ochratoxin A, and mycelium producti on after 4, 7, 10, 14, and 21 days of incubation at 25 degrees C. Incr easing concentrations of iprodione in the growth media resulted in gre ater reduction of cyclopiazonic acid, ochratoxin A, and mycelium produ ction at the end of each incubation period. More than 50% reduction of cyclopiazonic acid, ochratoxin A, and mycelium production was observe d when iprodione was added to growth media at a concentration of 5 mu g/ml of medium. Higher concentrations of iprodione (10 to 20 mu g/ml o f growth medium) inhibited the production of cyclopiazonic acid and my celium by A. flavus NRRL 1290 almost completely, but not the productio n of ochratoxin A and mycelium by A. ochraceus NRRL 3174.