In-vitro integrated management of alternaria porri affecting Allium cepa (onion)

Onion (Allium cepa) is a globally cultivated crop vulnerable to fungal diseases, notably those caused by Alternaria porri. This fungal pathogen significantly reduces yield, particularly during seed production. This study aimed to identify Alternaria porri affecting onions and to evaluate integrated management strategies involving synthetic fungicides, botanical extracts, and biological control agents. The research, conducted at Federal University Dutse, Nigeria, involved morphological and pathogenic identification of Alternaria porri., followed by phytochemical screening of Azadirachta indica (neem), and in vitro evaluation of antifungal efficacy using neem extracts, Trichoderma harzianum, and synthetic fungicides. Morphological and molecular analyses confirmed the presence of pathogenic A. alternata porri Phytochemical analysis of neem extract revealed multiple antimicrobial compounds, notably flavonoids and alkaloids. Synthetic fungicides showed the highest inhibition against Alternaria spp., followed closely by neem extract, while T. harzianum displayed strong antagonistic effects at higher conidial concentrations. Results support the effectiveness of integrating chemical, botanical, and biological methods to control Alternaria-induced onion diseases. The study recommends a sustainable approach that reduces reliance on chemical fungicides, mitigates environmental impact, and enhances disease control efficacy through integrated pest management (IPM).