如何防治水稻叶枯病（How to prevent the blight of rice）.docVIP

如何防治水稻叶枯病（How to prevent the blight of rice） How to control rice leaf blight Symptoms are also known as white leaf blast, ground fire, and thatch. The whole growth period can be damaged, the most serious damage in seedling stage and tillering stage, all organs can be infected, and the leaves are most susceptible to infection. There are 3 types of symptoms, such as invasion sites, varieties, disease resistance and environmental conditions. Leaf withered type: mainly damage the leaves, but also damage the serious disease starts from the sheath, leaf tips and margins, first appears dark green water soaked spots along the linear, quickly spots formed white spots, and then along the both sides of the leaf margin or ribs extended, brown, white spots edge was finally dry, clear boundaries. In resistant varieties on the lesion showed irregular wavy edge. Susceptible varieties leaves grayish green, water is fast, involution of Ralstonia solanacearum, and more in the upper leaves. Acute wilting type: seedling stage to tillering stage, the invasion of pathogenic bacteria from root or stem vascular wound diseases. The main stem or the incidence of more than 2 tiller leaf water loss at the same time, Ralstonia solanacearum, wilting death, the rest of the blade has Solancearum curl, and whole plant, there are only dead leaves. There are a large number of bacteria infected stem cavity pus, some basal sheath disease yellow or brown, a large number of yellow pus bacteria break extrusion overflow by hand. Some rice, tiller to booting stage, the flag leaf or the 1-3 midrib pale yellow spots along midvein extending up and down, up to the tip, sometimes issued sheath and blade folding, die were not heading. Brown or brown variant: see more resistant varieties, bacteria by leaf cutting or wound invasion, in the low temperature or adverse incidence condition, peripheral lesion necrosis reaction zone, the disease extended stagnation. Yellow type symptoms are rare, early leaves not withered