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Biocontrol of postharvest Alternaria decay in table grapes from Mendoza province

Stocco, A.F., Diaz, M.E., Rodríguez Romera, M.C., Mercado, L.A., Rivero, M.L., Ponsone, M.L.
Biological control 2019 v.134 pp. 114-122
Alternaria alternata, Metschnikowia pulcherrima, biological control, chitosan, coatings, cold, cold storage, disease control, fruits, fungicides, pathogens, phenology, postharvest diseases, postharvest storage, postharvest technology, sulfur dioxide, table grapes, transportation, vines, yeasts, Argentina
Postharvest diseases cause considerable loss of fruit during transportation and storage. Synthetic fungicides are primarily used to control them. However, the recent trend is to shift toward safer and more eco-friendly alternatives for the control of postharvest decays. In Argentina, Alternaria genus was cited as a postharvest pathogen on table grapes for the first time during 2010–2012 seasons. The aim of this study was to identify, by morphological and molecular techniques, Alternaria spp. strains isolated from table grapes cv. Red Globe in different phenological stages of vine and postharvest storage in Mendoza province. In addition, we intended to propose an alternative postharvest management to the use of sulfur dioxide (SO2) generators (traditional method). We searched for a lower environmental impacting substitute using the yeast strain Metschnikowia pulcherrima RCM2 and chitosan coatings as possible control agents. The results showed that the pathogen was present in all the stages studied and the 100% of the strains belonged to the species-group Alternaria alternata. Besides, chitosan coatings showed to be a good alternative method to SO2 generators. This work is focus on the study of the incidence of Alternaria spp. during the phenological cycle and postharvest storage of table grapes cv. Red Globe, and also on the evaluation of alternative strategies to the use of SO2 for the control of this disease during the extended cold storage.