Semi-commercial field evaluation of yeast formulations for control of mango postharvest decay caused by Botryosphaeriacean fungi in organic production.

Botryosphaeriacean fungi usually cause mango rot in the tropics. They cause quiescent infections, and symptoms are detectable only in advanced stages of fruit ripening, imposing that control strategies begin in preharvest. Biocontrol is one of the few alternatives to control postharvest decay of mango in organic or biological production. However, there is very few research specifically designed for organic mango production. The objective of this study was to evaluate four yeast strains applied in individual formulations to control postharvest decay of mango, as part of the integrated management of postharvest fruit rot decay using preharvest spraying in an organic orchard. In a first experiment, the antagonist yeast strains Saccharomyces cerevisiae ESA45, Saccharomyces sp. ESA46, Saccharomyces sp. ESA47, and Pichia kudriavzevii CMIAT171 were applied to artificial wounds in organic mango fruits inoculated with propagule suspensions of virulent strains of Lasiodiplodia theobromae and Neofusicoccum parvum. All treatments significantly increased the period until the detection of rot symptoms and reduced rot severity. Formulations containing starch+carboxymethyl celullose and the yeast strains were applied in two different production cycles (2014 and 2015/16) in a semi-commercial organic orchard. All treatments significantly reduced mango rot. Field spraying of Pichia kudriavzevii CMIAT171 reduced disease index in 69.4% in an average for the two years