Symptoms
Rice seedlings typically begin to show symptoms at the three-leaf stage. Initially, the tip of the leaf turns white, and this discoloration spreads along the main vein toward the base of the leaf. The condition then extends outward from the midrib to both sides of the leaf margins. As the disease progresses, the entire leaf becomes white, although some leaves may only show partial whitening. The leaf margins often remain green, while the leaf sheath loses its color and turns purple before eventually fading to yellow-brown. In some cases, the disease develops rapidly, with multiple green leaves showing lesions simultaneously, turning into white seedlings. New leaves and tiller leaves also become affected, though the progression of the disease can be slower in certain instances. Generally, by the 6th or 7th leaf stage, the affected leaves gradually regain their green color. However, the disease is most severe during the 4th and 5th leaf stages.Causes
According to available information, white seedling disease is commonly observed in Putian when urea is used as a base fertilizer. The occurrence of this condition is also influenced by climatic factors. Specifically, if the average temperature remains below 16°C for three consecutive days after sowing, the rice seedlings are more susceptible to the disease. This environmental stress can weaken the plants, making them vulnerable to nutrient deficiencies and other physiological disorders.Control Methods
1. Avoid using excessive amounts of urea as a base fertilizer in Putian. Instead, apply topdressing during the three-leaf stage, dividing the application into smaller portions to ensure even nutrient uptake. 2. Sow seeds on sunny days whenever possible to promote healthy growth and reduce the risk of disease development. 3. For fields already affected by the disease, applying trace elements such as zinc sulfate or ferrous sulfate can help alleviate symptoms. A recommended dosage is 1–2 kg of zinc sulfate per mu, and 1 kg of ferrous sulfate per mu. These nutrients can improve plant health and support recovery. 4. In addition to fertilization, maintaining proper water management and ensuring good drainage can further reduce the likelihood of disease occurrence. Regular field monitoring is also essential to detect early signs of the condition and take timely action.Wholesale Sriracha Sauce,Hot Selling Chili Sauce,Wild Alaskan Pollock Oil
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