The efficacies of antagonistic yeasts were also evaluated in vivo on tomato fruits. The results were found to be inconsistence to the in vitro assay, while all yeasts originally isolated from strawberry fruits were found to cause severe spoilage of tomato due their highly fermentative capabilities (Table 1). This finding suggested that the fermentative property should be taken into account in the selection of biocontrol agent for the control of posthavest diseases of soft fruits or vegetables.