Hypochlorous acid as a tool for sustainable plant disease management

As climate change intensifies, agriculture must meet the growing global food demand while reducing its ecological footprint. The negative impacts of conventional pesticides and fertilizers highlight the need for innovative, eco-friendly approaches to protect plant health. Sustainable disease management strategies are crucial for environmentally responsible crop production. Among emerging technologies, hypochlorous acid (HOCl) is gaining attention for its strong oxidizing properties, which make it an effective sanitizer and disinfectant. HOCl is unstable and rapidly degrades into H⁺ and OCl⁻ in aqueous solution without releasing toxic by-products, expanding its use in food safety, medical applications, and agricultural sterilization. Produced through electrochemical activation of water and NaCl, HOCl can be generated directly in situ. This study evaluated the effect of HOCl-treated water to improve plant health in two crops: Olea europaea and Solanum lycopersicum. Concerning olive, open-filed experiments were conducted to assess its efficacy against Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot disease. Treatments reduced the pathogen epiphytic population, although the effects decreased over time, suggesting the need for repeated treatments, especially during pruning and post-harvest. On tomato, field trials were performed to assess the HOCl effects on plant growth, development and defenses. Preliminary results showed that high concentrations of HOCl inhibited tomato growth, while diluted solutions had no significant effects. Moreover, the relative expression of defense-related genes showed the alteration of defense signaling pathways, such as those involving CHS and PR1. These findings suggest that HOCl, when properly managed, may represent a promising tool for sustainable crop protection.