A Novel Approach for Fungal Control with Ethyl Formate in Barley and Its Impact on Germination

Fungi can degrade grain quality, produce harmful mycotoxins, and hinder germination in the post-harvest stage, resulting in significant economic losses. Ethyl formate (EF) is an efficient and eco-friendly fumigant for controlling pest insects in grains, horticulture, and quarantine treatments. However, there is a lack of research on the antifungal activity of EF and its degradation products on barley seeds. In this study, fifteen fungal species, predominantly <i>Alternaria infectoria</i>, were isolated and identified from seven Australian barley samples. Efficacy results indicated that EF significantly inhibited fungal growth at a commercial concentration of 2.4 mmol/L, except for <i>Penicillium</i> sp. 2, <i>Fusarium chlamydosporum</i>, and <i>Rhizopus arrhizus</i>. To control these EF-tolerant fungal species, the EF concentration was increased to 5 mmol/L, which achieved a 100% inhibition rate. The degradation product of EF, formic acid, effectively inhibited all EF-tolerant fungi, requiring only 0.08 mmol/L in the in vitro study. There were no significant differences in vigor and germination rates in barley treated with EF at concentrations of 2.5, 3.7, and 5 mmol/L. Additionally, EF treatments led to a significant increase in the barley root length from an average of 9.1 cm in the control group to 13.2, 13. 6, and 12.3 cm at 2.5, 3.7, and 5 mmol/L. The findings suggest that EF could be a suitable alternative fumigant to safeguard grain from fungal infestation, particularly in the context of advancing agricultural practices and improving seed germination quality. The degradation compound, formic acid, may contribute significantly to the overall antifungal function of ethyl formate fumigation, particularly in high-humidity environments.