Résumé
In the recent decays, application of the fungicides has provided some concern in the scientific society. Recently, biological control was developed as an alternative to synthetic fungicides, and considerable success was achieved by utilizing antagonistic microorganisms for controlling postharvest diseases. In this present research, two yeast antagonists of Saccharomyces cerevisiae [04,69] applied instead of fungicide that it controlled blue mold of apple caused by Penicillium expansum. Blue mold agent isolated from infected apples. Dual culture, cell free metabolite and volatile test were used in vitro assay to evaluate as potential biological control agent against apple blue. In storage assays [in vitro assays], apple fruit wounds were inoculated with 40 microl of yeast cell suspension [10[7] cell/ml] followed 24h later by P.expansum [10[5] conidia/ml]. The apples were then incubated at 20[degree sign] C and 5 [degree sign] C. The inhibition varied among isolates of yeasts and ranged from 33.12% to 58.4%, in dual culture, from 54.93% to 72.87% in volatile metabolite and from 50.23% to 76.23% in cell free metabolite test. In the storage test, two isolates of S. cerevisiae reduced the decay area from 1416 to 1435 mm[2] compared to 3151.1 mm[2] in control after at 5 [degree sign] C. At 20[degree sign] C, the lesion area ranged from 1347 to 1598 mm[2] for the antagonist treatments compared to 3257.4 mm[2] for the control treatments. The two isolates of S. cervisiae were the effective isolates at both temperatures in this assay and could be two of important new biological control agents for apple blue mold