Alternaria brown spot is a fungal disease that affects citrus fruits, including oranges. It is caused by the fungus Alternaria alternata. Here are the symptoms of Alternaria brown spot that you should look out for in oranges:
- Brown or dark-colored spots: The disease typically starts as small, brown or dark-colored spots on the surface of the orange. These spots may appear sunken and can vary in size.
- Circular or irregular lesions: The spots can grow and merge together, forming circular or irregular lesions on the orange’s peel. The lesions may have a dark brown or black color.
- Raised, corky tissue: As the disease progresses, the affected areas can develop raised, corky tissue. This tissue may be rough to the touch and have a slightly sunken appearance compared to the healthy areas.
- Pitting: In severe cases, the lesions can cause pitting on the orange’s surface. The pitting may be shallow or deep, and it can affect the overall texture of the fruit.
- Spore production: When the lesions are moist, you may notice a dark, velvety fungal growth within or around the affected areas. This growth consists of spores produced by the Alternaria fungus.
It’s important to note that these symptoms can also be caused by other diseases or disorders. If you suspect Alternaria brown spot or any other disease in your oranges, it is recommended to consult with a local agricultural extension service, plant pathologist, or other experts who can provide accurate diagnosis and guidance for appropriate management strategies.
