Chitosan and salicylic acid as alternatives for the control of postharvest fungal diseases in blueberries (Vaccinium corymbosum)

Blueberry (Vaccinium corymbosum) has characteristics that make it a highly coveted fruit by the population that seeks benefits for their health, thus giving it economic and social relevance. However, it is a very perishable fruit. In the present work, Botrytis sp., Penicillium sp., and Alternaria sp. were isolated from blueberry, and molecularly identified. The in vitro effect of chitosan (CHI) and salicylic acid (SA) on the growth of these phytopathogens was then evaluated, as well as the incidence of the disease after the application of these treatments on blueberry. CHI at 1.5% achieved an in vitro mycelial growth inhibition of Botrytis sp., Penicillium sp., and Alternaria sp. by 93, 84, and 40%, respectively. Furthermore, a complete germination inhibition of Penicillium sp. and Alternaria sp. was accomplished; Botrytis sp. spores were less sensitive to chitosan treatment. The germination percentage of the phytopathogens was reduced by 90% using SA at 5 mM. The in vivo application of CHI at 1.5% and SA at 5 mM decreased the percentage of incidence of phytopathogens in blueberries harvested after storage period at 25°C, as compared to the control. Based on these results, SA and CHI represent an alternative for the control of phytopathogens in blueberry to eliminate the use of synthetic fungicides.