Alternaria species associated with 'moldy heart' on peaches in Argentina

'Moldy heart' caused by Alternaria spp has been previously reported in apples in Argentina. However, according to our knowledge this is the first report of Alternaria spp in 'moldy heart' affected peaches in this country. Direct isolation of the pathogen was performed on Dichloran-Chloramphenicol-Malt Extract-Agar. Seven strains were isolated and identified as A. alternata and one as A. tenuissima. Their toxicogenic potential (alternariol (AOH), alternariol methyl ether (AME) and tenuazonic acid (TA) production) was determined. The toxins were extracted with chloroform and determined by TLC. All strains produced AOH and AME while six of them were TA producers. The fungicides tested on agar were captan and mancozeb. At 2.5g/L (commercial concentration) both fungicides inhibited the germination of spores. Captan completely inhibited mycelial growth. The effect of the fungicide on toxin production was variable according to fungicide type, doses, strains and toxins considered