Efficacy of an electrolyzed water (Verdeviva) towards pathogens of fruit crops

There are increased activities in development and application of electrochemical disinfection cells using the electrochemical activation of salt aqueous solutions (electrochemical activated solutions or simply Electrolyzed Water)*. Their sterilizing effect is due to a mixture of inorganic oxidants such as HClO, ClO–, Cl2, OH-, which are effective for inactivating a variety of microorganisms (Tsuji et al., 1999; Bari et al., 2003; Fabrizio and Cutter, 2004; Al-Haq M. I. et al., 2005, ; Huang et al., 2008). The ability of EW to provide better microbial reductions also attributes to the fact that EW is freshly produced and used immediately. EW water has been demonstrated to sanitize food preparation surfaces and hospital equipment but several studies have been carried out also in plant protection by pre- and postharvest applications (e.g. Buck et al., 2002; Mueller et al., 2003; Yang et al., 2003; Abbasi and Lazarovits, 2006). In this study in vitro assays and field trials were conducted applying different concentrations of a type of EW called Verdeviva produced by Eva System® equipment (Industrie De Nora S.p.A.) starting from an aqueous solution of potassium chloride. An evaluation of conidial germination was carried out for the following fungal pathogens of pear/apple trees and stone fruits such as Pleospora allii (an. Stemphylium vesicarium), Valsa ceratosperma (an. Cytospora vitis), Neonectria galligena, Venturia inaequalis, Monilinia laxa and Phomopsis amygdali. A specific protocol (Donatoni et al, 2008) was adopted to test the bacteria Erwinia amylovora and Pseudomonas syringae pv actinidiae (Psa). The effectiveness of Verdeviva against the apple canker caused by N. galligena and the fire blight of pear (E. amylovora) in field were also evaluated. EC50 and MIC ranged from 0,31 to 3,92 mg/L and from 0,75 to 8 mg/L respectively for fungal pathogens except for V. inaequalis that showed higher sensitivity parameters (EC50 17,33 mg/L, MIC 30 mg/L). E. amylovora and Psa were completely inhibited at 8 and 5 mg/L of Verdeviva. Good control of N. galligena was showed in apple orchards at different infection degrees (27-64%) and trials performed in pear orchards against E. amylovora pointed out activity of Verdeviva higher than reference standards. Interesting possibilities to use Verdeviva as an alternative product in plant protection will be discussed also considering that its approval as a pesticide is on-going activity.