水稻白叶枯病和条斑病都是由风雨、流水作中短程距离传播的地区性流行病，也可随种子调运而在洲际传播。水稻白叶枯病在世界各大稻区均有发生，主要在亚太地区，可分为亚太流行区、西非流行区和中北美洲新病区。在中国，按耕作制度和病情可分为华南全年流行区、江淮中度流行区和北方短期流行区３个区域。稻条斑病仅在亚洲稻区发生，国内主要发生在籼稻、杂交稻，已从两广逐渐向北扩展到江淮流域。影响水稻白叶枯病发生流行的因素很多，品种抗病基因的布局和病菌小种的变异是病害流行长期和超长期预报的依据，气象因素和耕作水平是区域中期预报的主要依据，伏旱值是预测江淮稻区白叶枯病和细条病流行程度的重要指标。 Rice bacterial blight and leaf spot are both endemic epidemics that spread by wind, rain and running water over medium and short distances and can also be transmitted across continents as the seeds are transported. Rice bacterial blight has occurred in all major rice regions in the world, mainly in the Asia-Pacific region, and can be divided into endemic areas in Asia-Pacific, endemic areas in West Africa and new North-Central American ward. In China, according to farming system and disease, it can be divided into three regions: the endemic area in south China, the moderate prevailing area in JAC and the northern endemic area in north China. Rice leaf spot occurs only in the Asian rice area, which mainly occurs in indica rice and hybrid rice. It has been gradually expanded from Guangdong and Guangxi to the Yangtze River and Huaihe River. There are many factors that affect the prevalence of bacterial leaf blight in rice. The distribution of disease resistance genes and the variation of germ races are the basis for long-term and long-term forecast of disease epidemic. Meteorological factors and farming level are the main bases of regional medium-term forecast. It is an important index to predict the prevalence of bacterial blight and sliver disease in Jianghuai rice area.