Inhibition of Production of Cyclopiazonic Acid and Ochratoxin A by the Fungicide Iprodione‡

Abstract

Aspergillus flavus NRRL 1290 and Aspergillus ochraceus NRRL 3174 were grown on a glucose-salts medium and yeast extract-sucrose broth containing the fungicide iprodione at concentrations of 0, 1,3,5, 10, 15, and 20 μg of active ingredient per ml of growth medium. Cultures were analyzed for cyclopiazonic acid, ochratoxin A, and mycelium production after 4,7, 10, 14, and 21 days of incubation at 25°C. Increasing concentrations of iprodione in the growth media resulted in greater reduction of cyclopiazonic acid, ochratoxin A, and mycelium production at the end of each incubation period. More than 50% reduction of cyclopiazonic acid, ochratoxin A, and mycelium production was observed when iprodione was added to growth media at a concentration of 5 μg/ml of medium. Higher concentrations of iprodione (10 to 20 μg/ml of growth medium) inhibited the production of cyclopiazonic acid and mycelium by A. flavus NRRL 1290 almost completely, but not the production of ochratoxin A and mycelium by A. ochraceus NRRL 3174.