The effect of PAW on plants is complex and strongly correlated to the concentration of RONS in liquid phase, which can be influenced by several parameters such as: source type, power, type of water. In this view, two different corona plasma sources used for the treatment of tap water are presented. The first one is a scaled down source used to treat 0.5 liters of tap water for the treatment of plum trees infected by European stone fruit yellows associated with ‘Candidatus Phytoplasma prunorum’ presence by endotherapy in the field. The agronomic performances in terms of stem length and fruit productions were evaluated. The second one is a scaled-up source able to treat 5 liters of tap water for hydroponic systems. Subsequently, the effect of tap water and PAW in hydroponic systems was compared evaluating plants weight, leaf area, L-A-B indexes and water use efficiency. In both cases an in-depth analysis of electrical parameters of plasma sources and chemical parameters of PAW were realized to define the most important parameters for the scale-up of corona sources used for the treatment of tap water
