Biological control of the post-harvest pathogens Alternaria solani, Rhizopus stolonifer, and Botrytis cinerea on tomato fruit by Pichia guilliermondii

Abstract

SummaryThe yeast, Pichia guilliermondii, was evaluated for its activity in reducing post-harvest decay of tomato fruit caused by Alternaria solani, Rhizopus stolonifer, and Botrytis cinerea. The potential of using P. guilliermondii to control natural infections, and its effects on the post-harvest quality of tomato fruit were investigated. The results showed that a washed-cell suspension of the antagonistic yeast was effective at inhibiting all three pathogens, and tomato fruit treated with the antagonist at 107 CFU ml–1 or 108 CFU ml–1 had significantly lower incidences of disease and smaller lesion diameters. The concentration of antagonistic yeast had a significant effect. Higher concentrations of the antagonist gave a lower incidence of disease. Results for reducing the development of natural decay on intact fruit were similar to those for artificially-inoculated fruit, and the effectiveness of the antagonistic yeast as a biocontrol agent was significant for tomato fruit at three different stages of maturity. Compared to controls, the incidence of natural decay on antagonist-treated fruit decreased significantly, and none of the treatments impaired the quality parameters (e.g., weight loss, total soluble solids content, titratable acidity, ascorbic acid content and fruit colour).Thus, we conclude that the yeast, P. guilliermondii, can control several post-harvest diseases of tomato fruit and not affect tomato fruit quality.