Abstract:
Three yeast antagonists (two strains of Cryptococcus laurentii and one of Candida sake) from orange trees reduced incidence of
green mold by 80 to 95% when tested in wounded orange fruits inoculated with Penicillium digitatum and incubated at 7ºC for 30 days.
The yeasts inhibited conidial germination of the pathogen, but did not kill the spores. Effectiveness of the three yeasts as antagonists
was associated in part with their ability to rapidly colonize wound sites, despite low nutrient availability. Observations suggested that
production of extracellular matrix by the yeasts may have facilitated rapid wound colonization. Germination of P. digitatum conidia was
significantly inhibited when the pathogen and antagonists were in direct physical contact in a culture suspension. The results supported the
view that competition for nutrients is also a mode of action of yeasts against P. digitatum.
