Storage diseases are responsible for the majority of yield losses after harvest. Dry rot, caused by the filamentous fungus Fusarium solani is an example of an especially important disease agent affecting potato storages around the world. The study presented here examined the effects of nano silver as fungicides on controlling dry rot on aged potato tubers (6-months after harvest) of the cultivars ‘Agria’, ‘Marfona’ and ‘Santé’ and also on young potato tubers (1-month after harvest) of ‘Agria’ and ‘Santé’ cvs. The results showed fungal growth on aged tubers of cv. ‘Marfona’ was significantly reduced by applications of nano silver three days after inoculation. However, fungal growth was markedly increased on cv. ‘Santé’ cv three hours after inoculation. These data suggested that the cv. ‘Marfona’ is has greater tolerance, dry rot when compared to that of cv. ‘Santé. Furthermore, the timing of nano silver applications appeared to have an impact on dry rot control efficacy on potato tubers. Therefore, efficacy of nano silver may depend greatly on application timing and be limited to cultivars with certain genetic properties. Moreover, the most successful timing of the nano-silver treatment seems to be one hour after inoculation of young tubers. Although, treatment after three hours of inoculation reduced growth of mycelium on young tubers of both cultivars, but its effectiveness was lower when applied one hour after inoculation. Consequently, shorter the time of nano-silver treatment, the more effective will be the controlling spread of the dry rot infections on tubers, during storage.

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