Fungicide effect on Aspergillus section Nigri

The species belonging to the genus Aspergillus section Nigri, and particularly A. carbonarius, are the main responsible for ochratoxin A (OTA) production in grapes. The effect of 23 fungicides commonly used in vineyard on the species belonging to the section Nigri, A. aculeatus, A. awamori, A. carbonarius, A. foetidus, A. japonicus and A. niger was evaluated in vitro, on detached berries and in vineyard. In vitro assays showed that folpet, tolylfluanid, mepanipyrim and cyprodinil+fludioxonil persistently inhibited the mycelial growth of the tested strains. Azoxystrobin, procymidone, pyrimethanil and some IBS fungicides had a slight and transient negative effect and mancozeb and difenoconazole were active only against one or few species. The highest protection of the inoculated berries and OTA reduction was achieved by mepanipyrim, pyrimethanil and cyprodinil+fludioxonil, followed by folpet, tolylfluanid and procymidone. Similar results were obtained by pyrimethanil and cyprodinil+fludioxonil on cv Merlot in vineyard, while procymidone and moreover fenhaxamid did not induce a decrease in A. carbonarius infection and in OTA accumulation. Therefore the anilinopyirimidine and pyrrole fungicides showed either in vitro or in vivo the highest effectiveness against the ochratoxigenic fungi commonly associated with grape clusters.