ISOLATION AND CHARACTERIZATION OF FUNGAL PATHOGENS FROM ONION SEEDLINGS

Abstract

The prevalence of fungal pathogens in agricultural crops poses significant challenges to crop production and food security worldwide. This study aimed to isolate and characterize two major fungal pathogens, Alternaria porri and Penicillium digitatum, from diseased onion (Allium cepa) seedlings. Alternaria porri, known for causing leaf blight, and Penicillium digitatum, responsible for post-harvest decay, were successfully isolated and identified based on their colony morphology, pigmentation, and growth rates. Pathogenicity tests revealed that Alternaria porri caused severe leaf blight with a disease severity score of 4.3, while Penicillium digitatum primarily affected stored onion bulbs, with a disease severity score of 3.8. Growth rates for the fungi were recorded at 10.5 mm/day and 12.0 mm/day, respectively, with optimal growth observed under temperatures between 25°C and 30°C. The findings underscore the potential for significant yield and post-harvest losses due to these pathogens, highlighting the critical need for integrated disease management strategies. Early detection, the use of resistant cultivars, and targeted fungicidal treatments are recommended to reduce crop damage and ensure food security.