Mycotoxin production by Alternaria alternata strains isolated from red delicious apples in Argentina

Eleven Alternaria alternata strains isolated from Red Delicious apples in cold storage in Argentina, were tested for alternariol and alternariol methyl ether production in laboratory media and in whole fresh fruits. Most of them were able to produce both toxins in all media. They were detected also in mycelium free filtrates from liquid cultures and in asymptomatic tissues from inoculated fruit. Thus, in the evaluation of mouldy core incidence in apples, the presence of A. alternata toxins in tissues should be considered even in the absence of mycelia.