白叶枯病、纹枯病和稻瘟病称为水稻的三大病害,特别是前两种病害在我省新老稻区,有逐年加重的趋势,有些年份稻瘟病发生也较重.大发生年,一般减产10-30%,严重的可达50%以上,成为水稻生产上的大障碍.白叶枯病是一种细菌病害,其症状可分为三种类型:病斑从叶尖开始沿中脉或叶缘 Bacterial blight, sheath blight and blast are called the three major diseases of rice, especially the first two diseases in the province of new and old rice area, increasing year by year trend, in some years the occurrence of rice blast is also heavier. Year, the general reduction of 10-30%, a serious up to 50% or more, become a major obstacle to rice production.Be bacterial leaf blight is a bacterial disease, the symptoms can be divided into three types: lesion from the leaf tip Along midrib or leaf margin