Cold Plasma as a new technology in the sustainable management of plant diseases

In the last decade the need of sustainable, innovative and competitive tools is a primary goal for management of plant disease. Non-thermal plasma, also known as cold plasma, is a green technology for environmentally safe control of phytopathogens on fruits, seeds and plants. It is an ionized gas, composed of a mixture of ions, electrons, radicals, reactive oxygen and nitrogen species (RONS) and UV radiation that have a specific role in the decontamination activity, carried out directly by air plasma or indirectly by water activated by plasma (PAW). The working conditions at atmospheric pressure and ambient temperature makes this technology suitable for biological application. Decontamination efficacy was investigated in in vitro assays against different species of fungi and was evaluated the different susceptibility to the plasma, in relation to the different melanisation level, in two fungal strains. Low melanized strains of Botrytis cinerea and Aspergillus carbonarius was used to analyzed the melanin role in the plasma treatment efficacy. Shorter treatment times are required to inactivate the germination of low melanized conidia as compared to melanized ones. This result demonstrates the protective role of fungal melanin against oxidative agents, as the plasma can be. The decontamination activity of plasma treatment was confirmed also on seeds, artificially inoculated with Cladosporium fulvum and Fusarium spp., and on cherry fruits artificially inoculated with B. cinerea and M. fructicola. Different configurations of plasma sources, i.e. Surface Dielectric Barrier Discharge (SDBD), Atmospheric Pressure Plasma Jet (APPJ), Volume Dielectric Barrier Discharge (VDBD), were used and allow to obtain different rate of decontamination efficacy in relation to the treated sample.