Identification, Pathogenicity, and Prevalence of Fungal Species Responsible for Post-Harvest Spoilage of Sweet Oranges (Citrus sinensis) in Dekina, Kogi State, Nigeria

Oranges (Citrus sinensis) are a vital source of nutrients and hold significant economic value in the global fruit industry. However, postharvest spoilage remains a major challenge, particularly in regions with limited infrastructure for storage and transportation. This study aims to identify the fungal pathogens responsible for the spoilage ofss sweet oranges in Dekina Local Government Area, Kogi State, Nigeria. A total of 162 sweet orange fruits were collected from three major markets in the area, with 54 fruits exhibiting visible signs of spoilage selected for further analysis. Fungal isolation was carried out using Potato Dextrose Agar (PDA), and the species were identified using a combination of morphological and molecular techniques. Six fungal species were isolated: Aspergillus niger, Aspergillus fumigatus, Penicillium digitatum, Fusarium oxysporum, Aspergillus terreus, and Fusarium solani. The occurrence, distribution, and pathogenicity of these fungi were evaluated, with Aspergillus terreus emerging as the most pathogenic (96 mm decay rate) and Aspergillus niger (22% occurrence) as the most prevalent across the markets. The findings underscore the critical need for improved postharvest handling, storage, and transportation practices to mitigate spoilage and reduce economic losses. Furthermore, the study highlights the importance of educating stakeholders within the citrus supply chain about the risks posed by fungal contamination and the necessary preventive measures. This research contributes valuable data to the limited body of scientific literature on postharvest spoilage of oranges in the region and provides a foundation for future efforts in developing effective management strategies. Additionally, the study offers crucial insights for agricultural extension services and potential investors in the orange juice industry, contributing to the sustainable development of citrus production in Nigeria.