Peppermint and tarragon essential oils encapsulated in copper nanoparticles: A novel approach to sustainable fungal pathogen management in industrial crops

The management of fungal pathogens like Fusarium oxysporum in agriculture is crucial due to their detrimental effects on crop yields and food security. Traditional chemical fungicides, while effective, raise environmental and health concerns, prompting the search for safer alternatives. This study explores the use of plant-derived essential oils (EOs) and copper nanoparticles (Cu-NPs) as environmentally friendly solutions for fungal disease management. Peppermint (Mentha piperita L.) and tarragon (Artemisia dracunculus L.) EOs were evaluated for their antifungal properties, both alone and when encapsulated in Cu-NPs, across a wide range of concentrations (60–800 ppm). The results demonstrated that peppermint and tarragon EOs exhibited significant antifungal activity, with up to 80 % inhibition of F. oxysporum mycelial growth at 360 ppm and 720 ppm by day 3, although their efficacy declined to 69–73 % by day 12. Cu-NPs alone exhibited consistent and high antifungal activity, achieving 75.3 % and 86.3 % inhibition at 420 ppm and 840 ppm, respectively, by day 3, with sustained and near-complete inhibition maintained through day 12. Encapsulation of EOs in Cu-NPs markedly enhanced their antifungal performance and stability, with encapsulated peppermint EO achieving 100 % inhibition at 800 ppm, and encapsulated tarragon EO requiring only 400 ppm to reach the same level of inhibition by day 3. Both retained high inhibition levels through day 12. Morphological analyses revealed pronounced structural damage in F. oxysporum mycelium treated with Cu-NPs and EO–Cu NP formulations, confirming enhanced antifungal action. This comparative evaluation of unencapsulated versus encapsulated treatments at matched concentrations highlights the synergistic potential of EO–Cu NP systems. These findings underscore the potential of combining Cu-NPs and EOs as a dual strategy for sustainable fungal disease management in agriculture. Future research should focus on optimizing formulation ratios and field-level application methods to enhance their practical deployment and cost-efficiency.