Southern blight, also known as southern stem blight, is a fungal disease that affects a variety of plants, including sweet potatoes. It is caused by the soil-borne fungus Sclerotium rolfsii. When it infects sweet potatoes, it can cause significant damage to the plants and reduce crop yield. Here are some symptoms of southern blight to look out for in sweet potatoes:
- Wilting and Yellowing Leaves: Infected sweet potato plants may exhibit wilting and yellowing of leaves. The wilting usually starts on one side of the plant and gradually spreads to other parts.
- Stem Rot: Southern blight typically causes a soft rot of the stem at or near the soil line. The infected portion of the stem may become water-soaked, turn brown, and eventually collapse. White fungal mycelium can often be seen on the affected area of the stem.
- White Mycelium: The fungus produces a white cottony mycelium, which can be observed on the stem, near the soil line, and sometimes on the leaves. This mycelium may also develop small, tan to brown, spherical structures called sclerotia.
- Sudden Plant Death: In severe cases, infected sweet potato plants may die rapidly, showing a sudden collapse of the entire plant.
- Stunted Growth and Poor Yield: Southern blight can lead to stunted growth and reduced yield of sweet potatoes. Infected plants may produce fewer and smaller tubers compared to healthy plants.
It’s important to note that these symptoms can also be caused by other factors, so it’s essential to confirm the presence of southern blight through laboratory testing or by consulting with a plant pathologist or agricultural extension specialist. If you suspect southern blight in your sweet potato crop, it’s advisable to take action promptly to minimize the spread of the disease and protect your plants.
