Alternaria leaf spot is a fungal disease that can affect sweet potatoes. Here are some symptoms to look out for:
- Leaf Lesions: Alternaria leaf spot typically begins as small, dark brown to black lesions on the leaves. These lesions may have a concentric ring pattern and can increase in size over time.
- Leaf Spots: As the disease progresses, the lesions may expand and coalesce, forming larger irregularly shaped spots on the leaves. The spots can be surrounded by a yellow halo.
- Leaf Yellowing: Infected leaves may show yellowing around the lesions or throughout the entire leaf. This yellowing can be a result of the pathogen affecting the leaf tissue or due to the plant’s response to the infection.
- Leaf Death: In severe cases, the infected leaves can die off, leading to defoliation. This can weaken the plant and impact overall growth and yield.
- Stem and Vine Lesions: Alternaria leaf spot can also cause dark lesions on the stems and vines of sweet potato plants. These lesions may appear sunken and can lead to stem cankers and vine dieback.
- Black Spores: Under favorable conditions, you may observe dark, velvety spore masses within the lesions. These spores are usually dark brown to black and are a characteristic feature of Alternaria fungi.
It’s important to note that other diseases or environmental factors can cause similar symptoms, so it’s advisable to consult with a plant pathologist or agricultural expert for a proper diagnosis if you suspect Alternaria leaf spot or any other disease in your sweet potatoes.
