Background: Apples often experience postharvest damage due to being attacked by
mold organisms. Several groups of molds such as Aspergillus sp., Penicilium expansum, Botrytis
cinerea, and Venturia sp. can cause a serious postharvest disease exhibited as watery regions where
areas of blue-green tufts of spores develop. Current methods using fungicides to control pathogenic
fungi can cause resistance if applied in the long term. An alternative procedure using yeast as a biological
agent has been found.
Objective: The aim of this study is to screen potential yeast, which has the ability to inhibit the
growth of Aspergillus brasielensis (isolate A1) and Aspergillus flavus section flavi (isolate A17)
isolated from apple fruits.
Methods: Antagonism test using YMA dual culture medium using in vitro assays and ITS rDNA
identification were performed.
Results: The result showed that 3 out of 19 yeast isolated from Cerbera manghas L, T1, T3 and T4,
demonstrated the potential ability as a biocontrol agent. ITS rDNA identification demonstrated that T1
has a similarity to Rhodotorula mucilaginosa while T3 and T4 were identified as Aureobasidium sp.
nov. The 3 isolates exhibited the ability to reduce the growth of A. brasiliensis sensu lato better
than dithane 0.3% with a Disease Incidence (DI) of 100% and a Disease Severity (DS) value of 45%.
Only isolate T1 and T3 were able to reduce decay symptoms in apples inoculated with A. flavus sensu
lato (with DO and DS were 100% and 25%, respectively) compared to dithane pesticides 0.3%.
Conclusion: This study indicated that competition between nutrients occurs between pathogenic
molds and under-yeast in vitro and in vivo conditions. However, further studies in the future might
be able to elucidate the ‘killer’ activity and interaction with the pathogen cells and the bio-product
production using Rhodotorula mucilaginosa and Aureoubasidium namibiae strains to control postharvest