Antifungal properties of Eucalyptus essential oils against devastating fungi in Australian wheat and canola cultivation

InformationThis study evaluated the antifungal activity of eucalyptus essential oils against three major phytopathogenic fungi: Fusarium pseudograminearum, Pyrenophora tritici-repentis, and Sclerotinia sclerotiorum, which are the causal agents of crown rot and yellow leaf spot in wheat, and stem rot in canola, respectively.Forty eucalyptus essential oils were initially screened at two concentrations: 10 µL per Petri dish (146.93 ppm v/v) and 50 µL per Petri dish (734.65 ppm v/v).The preliminary screening showed that oils applied at 50 µL per dish significantly inhibited the mycelial growth of all three pathogens compared to the untreated control (p < 0.05).Based on these results, the 20 most effective oils were selected for detailed dose-response assays across a broader concentration range, including 2.5, 5, 10, 20, 30 and 40 µL.Increasing concentrations consistently resulted in greater mycelial growth inhibition.The most active oils, ET289 and EA165, achieved ED₉₀ values of 20 µL per Petri dish against F. pseudograminearum.Oils EP294 and EF17 suppressed P. triticirepentis by 90-100% at just 5 µL per dish.For S. sclerotiorum, oils EF17 and EC162 produced 89-100% inhibition at 20 µL per dish.Overall, the results demonstrate that the selected eucalyptus essential oils possess strong, concentration-dependent antifungal properties and highlight their potential as environmentally sustainable alternatives to synthetic fungicides for crop protection.