Synergistic effects of Vernonia amygdalina nanoemulsions in antifungal action and defense enzyme activation

Gray mould disease, caused by Botrytis cinerea, is a significant threat to tomato production. This study investigates the effects of Vernonia amygdalina nanoemulsions (VNFs) on defense enzyme activities in tomatoes under postharvest conditions (25 ± 2°C and RH 85%). Two formulations, F5 and F7, were applied to artificially inoculated fruits and compared with benomyl-treated and untreated controls. F5 demonstrated superior efficacy, inducing elevated activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and polyphenol oxidase (PPO), with sustained levels throughout storage. F7 exhibited prolonged phenylalanine ammonia-lyase (PAL) activity, indicating systemic resistance. VNFs outperformed synthetic fungicides by combining antifungal properties with host defense priming, reducing fungal growth and enhancing tomato immunity. This study highlights the potential of VNFs as eco-friendly alternatives to synthetic fungicides, offering sustainable strategies for postharvest disease management. Future work should focus on molecular pathways and field-scale validation of these promising formulations.