University of Florida Institute of Food and Agricultural Sciences photo
A new study has identified several fungal pathogens associated with preharvest sweet orange fruit spoilage. It provides insights that could help citrus growers better understand and manage fruit rot problems in the grove.
The research, “Morphological Identification of Fungi Associated with Preharvest Spoilage of Sweet Orange (Citrus sinensis L.) Fruit in Bilo Nopha, Southwestern Ethiopia,” was published in the journal Scientific Reports. The authors are Gobena Adeba, Tekalign Kejela and Tesfalem Atnafu of Mattu University in Ethiopia.
Researchers collected 240 diseased sweet orange fruit samples from six orchards and isolated 430 fungal samples from those fruits. Their goal was to determine which fungi were most commonly associated with preharvest fruit spoilage.
The most frequently detected fungus was Pseudocercospora, which appeared in 45% of the samples. It was followed closely by Colletotrichum at 42.1%. Other fungi identified included Alternaria (30.4%), Rhizopus (27.1%), Fusarium (17.5%) and Phytophthora (17.5%).
The researchers also evaluated how aggressive each fungus was. Pseudocercospora proved to be the most damaging, causing the highest disease severity in healthy fruit. Phytophthora and Colletotrichum were also highly pathogenic, while Alternaria caused moderate disease and Fusarium showed relatively low pathogenicity.
One important finding for growers is that the most problematic fungi thrived under warm conditions. Most of the pathogens grew best between 77 and 86 degrees Fahrenheit. The study also emphasized that high humidity, rainfall and extended periods of fruit wetness favor infection and disease spread.
The authors noted that grove conditions can significantly influence disease pressure. Dense canopies that trap moisture create favorable conditions for fungal development. They suggest that practices such as pruning, maintaining proper tree spacing and removing infected plant material can help reduce inoculum levels and slow disease spread.
While the study was conducted in Ethiopia, its findings reinforce lessons that apply to citrus-growing regions worldwide. Diseases caused by Pseudocercospora, Colletotrichum and Phytophthora continue to threaten fruit quality and yield. The researchers concluded that these fungi are the primary contributors to preharvest fruit spoilage and that effective disease management programs are essential for reducing losses and sustaining citrus production.
Share this Post