Control methods of water chestnut stem blight caused by death of withered and yellowed plants of stems and leaves

Stem blight of water chestnut

Water chestnut stem blight is mainly harmful to leaf sheath, stem and leaf. At the base of the infected leaf sheath, dark green irregular water stains appeared at the base, and then spread to the whole leaf sheath. after drying, the diseased part was grayish white with short striped black spots. The stem was infected with water stains, dark yellow, soft and sunken, with black dots or short linear spots. With the development of the disease, the disease spot expanded upward into long strips of withered yellow spots, resulting in dry and yellow stems and leaves. In severe cases, the whole stem dies.

The pathogen overwintered with mycelium on the soil and the remains of water chestnut disease, while the new producing area took the bacterial water chestnut corm as the primary infection source, and the spores spread through wind, rain and irrigation water. Rain Water was frequent, heavy rainfall and easy to occur. In addition, the water chestnut fields with low-lying terrain, early closure, poor ventilation and light transmission, partial application of nitrogen fertilizer, overgrowth and tender stems were seriously affected.

For water chestnut fields with stem blight, 25% carbendazim wettable powder 250 times or 50% carbendazim 800 times wettable powder can be used in the early stage of the disease, once every 7-10 days, 3-4 times in a row, to control the spread of the disease. In addition, rational fertilization, increase the application of phosphorus and potassium fertilizer and farm fertilizer, especially silicon-containing phosphate fertilizer, ensure adequate nutrients, improve physiological and metabolic function, increase the thickness of silicon in seedling epidermis, and enhance the disease resistance of water chestnut plants.