Morphological identification of fungi associated with preharvest spoilage of sweet orange (Citrus sinensis L.) fruit in Bilo Nopha, Southwestern Ethiopia

Sweet orange (Citrus sinensis L.) is a major fruit crop globally, but fungal pathogens have severely impacted its yield. Bilo Nopha, known for high-quality sweet oranges, has recently faced significant preharvest spoilage. This study aimed to isolate fungal pathogens associated with preharvest spoilage of sweet orange (Citrus sinensis L.) fruit in Bilo Nopha, southwestern Ethiopia. In the present study, a total of 240 symptomatic orange fruit samples were collected from six orchards of study area and fungi pathogens were isolated and characterized to genus level following standard microbiological techniques. A total of 430 fungal isolates were recovered. Pseudocercospora spp. were most prevalent (45.0%), followed by Colletotrichum spp. (42.1%). Alternaria spp. showed moderate prevalence (30.4%) with significant site variation (15.0-37.5%, P < 0.05). Rhizopus spp. were consistent across sites (20-30%, total 27.1%), while Fusarium and Phytophthora spp. had the lowest rates (17.5% each). Pseudocercospora spp., Colletotrichum spp., and Phytophthora spp. were identified as the primary fungal pathogens, whereas Alternaria spp., Rhizopus spp., and Fusarium spp. were involved as secondary or opportunistic pathogens. Species-level identification and targeted management are recommended to reduce losses and sustain production.