Post-harvest control of gray mold in table grapes using volatile sulfur compounds from Allium sativum.

Background: This study proposes the use of volatile sulfur compounds derived from garlic (Allium sativum) extracts applied via gas for the control of Botrytis cinerea, which causes post-harvest disease in table grapes. The effects of the volatile compounds emitted by garlic extract and sodium metabisulfite on conidia germination of B. cinerea were evaluated in vitro to assess their effectiveness at controlling grey mold on grapes stored at different temperatures.

Results: Diallyl disulfide, diallyl trisulfide and allicin were identified and quantified in a garlic extract using reversed-phase high-performance liquid chromatography. The volatile compounds emitted by the garlic extract in the form of allicin and diallyl trisulfide inhibited conidia germination of B. cinerea in vitro and significantly reduced the lesion diameters on stored grapes, which were similar to the effects of sodium metabisulfite, while the diallyl disulfide did not have any effect. The sulfhydryl groups of cysteine or reduced glutathione completely reversed the antifungal effect of these compounds.

Conclusion: The antifungal activity that allicin and diallyl trisulfide, which are the volatile compounds emitted by a garlic extract, exerted on conidia germination of B. cinerea may be considered as an alternative for the control of gray mold in table grapes after harvest.