Efficacy semi-commercial trials of native yeasts: Pichia membranifaciens and Cryptococcus victoriae on conservation medium and length pears, in northern patagonia, Argentina.

LUTZ MARIA CECILIA; LOPES CHRISTIAN ARIEL; SOSA MARIA CRISTINA; GRAMISCI BETINA; SANGORRIN MARCELA PAULA

Simposio; III International Symposium on Postharvest Pathology; 2015

Antagonistic behavior of native yeasts: Pichia membranifaciens NPCC1250 and Cryptoccocus victoriae NPCC1263 on Botrytis cinerea and Penicillium expansum, was evaluated in semi-commercial conditions in two organic packinghouse (A and B) of Neuquén, Argentina. In line-packaging, applications were performed on D´Anjou and Packham´s pear fruit. Yeast biomass was produced in cane molasses (12.8 g/L) and urea (0.6 g/L). About 400 kg of fruit were sprayed with yeast suspension (1011CFU/mL).Treated fruit was packaged and stored in commercial storage chamber (-1/0°C, 95% RH). During2012, the effect of yeasts alone and with CaCl2 (2% w/v) was evaluated.At 90 days, in (B) on D´Anjou pears, yeasts with CaCl2 reduced the incidence of P. expansum more than 60% and Cr. victoriae plus CaCl2 fully controlledto B. cinerea. Packham´s pears were evaluatedat 160 days. The CaCl2improved the antagonism of Cr. victoriae against P. expansum. In (A), P. membranifaciens controlled 83% both pathogensand Cr. victoriae 100% to B. cinerea. In (B), P. membranifaciens controlled50% and 56% the incidence of B. cinerea and P. expansum, respectively; while, Cr. victoriae controlled 72% of B. cinerea. In 2013, the effect of yeasts (1011 CFU/mL) alone or in mixture (1:1) with CaCl2 2% (w/v) was evaluated. At 90 days, in D´Anjou pears, P. expansum was controlled by the three treatments in 82% and B. cinerea by P. membranifaciens and yeast mixture. In general, the mixture of yeasts was more effective than alone. While, in Packham´s, P. expansum was completely controlled by Cr. victoriae and the mixture, and by P. membranifaciens alone, in 88%; while B. cinerea was totally controlled by P. membranifaciens. The number of cells sprayed of yeast was reduced by the delivery system employed in at least two orders of magnitude. The yeasts colonized the fruit surface, reaching 107 and 108 CFU/cm2 of fruit. This safe technology based on yeasts, could significantly reduce the incidence of postharvest diseases of pears under commercial conditions.