Detection and identification of Alternaria alternata in table grapes cv. Red globe

STOCCO A.F.; RODRIGUEZ ROMERA M.; DIAZ M.; COMBINA M.; PONSONE L.

Bento Gonzalves

Congreso; 39º Congresso Mundial de la Viña y el Vino; 2016

Organizacion Internacional de la Vid y el Vino (OIV)

In previous studies conducted in the EEA Mendoza it was observed for the first time a disease that has not been previously cited for Argentina table grapes cv. Red Globe during post-harvest stage. Subsequently, it was determined that the rot was caused by Alternaria species. The hypothesis that the pathogen comes from field have not been proved and characterized for this fruit. The aim of this study was to evaluate by morphological and molecular Alternaria species isolated from table grapes in different maturity stages of vine and post-harvest storage in the region of Mendoza, in order to know the disease cycle in the vineyard ecosystem. Isolations where performed during six vine physiological stages: flowering, peppercorn, pea beans, veraison, harvest and postharvest (30, 60 and 90 days). While incidence of Alternaria genus was found in all stages of the analyzed phenological stages, the highest incidence was detected during flowering. Representative strains of each stage were isolated and identified to species level by morphological description. Then, molecular identification was carried out in order to establish the percentages of occurrence of the pathogen in each stage and species groups that develop in Mendoza vineyards. The results showed that the pathogen was present in all the successive stages studied; from flowering to postharvest. Fifty strains studied and molecularly analyzed in full (100%) were found to be of the genus Alternaria, 94% were positive for the group of species A. alternata. The remaining 6% must be re-evaluated to determine whether other groups belonging to different species of A. alternata. This is the first study about the Alternaria species incidence during the phonological cycle of cv Red Globe table grapes berries and his behavior during post-harvest storage.