Abstract
INTRODUCTION: Identifying pathogenic fungi from vegetable is a critical first step in disease management and development of effective plant-based antifungal agent, aligning with environmentally friendly and sustainable agricultural practices. This study aimed to isolate, identify, and characterize the major fungal pathogens of vegetables and to evaluate the antifungal efficacy of selected plant extracts against vegetable pathogenic fungi. Therefore clear identification is crucial for designing effective management protocols against these persistent fungal threats in Western Hararghe, Ethiopia. METHOD: Diseased onion samples (leaves, bulbs, and roots) and pepper samples (leaves and fruits) were collected from Gemechis and Boke district, Western Hararghe, Ethiopia, respectively, from July 2023 to January 2025. Data were analyzed using a Completely Randomized Design (CRD) and ANOVA. Three medicinal plants (Allium sativum, Azadirachta indica, and Acokanthera schimperi) were selected based on traditional usage and literature evidence. Crude extracts were prepared using maceration method, while essential oils were obtained through hydro distillation, using Clevenger apparatus. The chemical composition of the crude extracts was assessed using standard phytochemical screening and essential oils was analyzed by using gas chromatography-mass spectrometry (GC-MS). Antifungal activity of both extract was evaluated using the agar well diffusion method and detached leaf assay for obligate biotroph. RESULT: A total of six major fungal pathogens (Peronospora destructor, Rhizoctonia solani, and Fusarium oxysporum from onions; and Erysiphe species, Sclerotinia sclerotiorum, and Aspergillus niger from pepper) were identified. Phytochemical screening of these selected plants confirmed the presence of alkaloids, flavonoids, phenolics, tannins, and sulfur compounds in the crude extracts. Antifungal assays results demonstrated that the plant extracts significantly inhibited fungal growth, particularly at higher concentrations (200 µl/ml). Acokanthera schimperi showed the highest antifungal activity, followed by Azadirachta indica, while Allium sativum exhibited moderate effects. CONCLUSION: The findings underscored the potential of botanical extracts as environmentally friendly alternatives for managing fungal diseases in vegetable crops.