Use of 2E-Hexenal as an Alternative to Synthetic Fungicides for Pythium Leak Management in Stored Potatoes

Abstract Pythium ultimum , the causal agent of Pythium leak, is a major postharvest pathogen of potatoes, leading to significant losses in storage. Current management strategies rely on fungicides and proper storage conditions, but there is an increasing need for alternative, organic-compatible solutions. This study evaluated the efficacy of the plant-derived volatile compound 2 E -hexenal in controlling P. ultimum both in vitro and in storage conditions. In vitro experiments demonstrated that 2 E -hexenal completely inhibited the growth of P. ultimum at a concentration of 2.5 µL/L. Large-scale storage studies, including tuber inoculation trials and naturally infected tuber trials conducted in 2016, 2020, and 2023, showed that 2 E -hexenal treatments significantly reduced disease severity and incidence compared to untreated controls. Over multiple storage trials, disease severity was reduced by up to 85%, and disease incidence was consistently lower in treated tubers. Furthermore, in 2023, 2 E -hexenal treatments outperformed phosphorous acid, reducing disease severity by an additional 50%. These findings indicate that 2 E -hexenal has strong potential as a fumigant for controlling Pythium leak in stored potatoes, offering an alternative to conventional fungicides and meeting the growing demand for organic disease management strategies.