How to prevent rice sheath blight? Beware of high temperature and high humidity weather

Sheath blight, also known as banded leaf blight, has a great impact on the growth and development of rice. It not only weakens the absorption capacity of the root system, but also affects the photosynthesis of leaves, resulting in an increase in empty and shriveled grains, a decrease in 1000-grain weight and a decline in yield. Therefore, attention should be paid to the prevention and control of sheath blight in production. The following introduces the main symptoms, occurrence characteristics and control methods of this disease for reference.

Main symptoms When rice leaf sheaths are infected, small dark green water-soaked spots with blurred edges appear near the water surface, later expanding into oval or cloud-like shapes, with the center grayish green or grayish brown. When humidity is low, the center is pale yellow or grayish white, and the central tissue is damaged and becomes transparent, with dark brown edges. When the disease is severe, several lesions merge to form large lesions, appearing as irregular cloud-like spots with yellowed edges. When the disease develops quickly, the lesions are dirty green, and the leaves rot quickly. When stems are damaged, they are initially dirty green, later turning grayish brown, often unable to head, and those that do head have more shriveled grains. When humidity is high, white net-like mycelia grow on the diseased parts, later gathering into white mycelial masses to form sclerotia. The sclerotia are dark brown, shaped like mouse droppings, easy to fall off, and once they fall into the field they become the source of infection for the following year.