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稻瘟就是稻热病,是水稻生产中的主要灾害之一。它的分布,普及全国的水稻区。不同的地区,只在发生的程度上有差别而已。北从松花江,南到海南岛,东起台湾,西到云南,都有这个病害严重发生的报导。这种病害的发生,以温度和湿度都相当高的时间和地区最严重。1年之中,以暑热最烈期的前后为主要的发生期。在这时期中,病害的轻重,和流行的程度,就决定于湿度和雨量。湿度大,降雨的日数多,时间长,就有严重发生和大流行的危险。又因水稻是高温植物,在生长期间遇到反常的低温,也能降低抗病力,而引起病害流行。病害的发生,和水稻的种类也有关系。一般说来,籼稻的抗病力比粳糯稻强。但在各类之中,品种间的差异,也很显著,不可一概而论。病害程度上的差别很大。条件不利于病害发生时,即使有病,不过在叶片上产生少数的斑点;对于产量的影响很小。但是在发生严重的时候,可以使水稻成片枯死,不能抽穗,造成颗粒无收的局面。在普通的情况下,叶斑的
Rice blast is rice fever and is one of the major disasters in rice production. Its distribution, popularization of the country’s rice area. Different regions only differ in their degree of occurrence. North from the Songhua River, south to Hainan Island, east of Taiwan, west of Yunnan, there is a serious occurrence of this disease reported. The occurrence of this disease, the temperature and humidity are quite high time and area the most serious. In 1 year, with the hottest period before and after as the main period. During this period, the severity of the disease, and the extent of the epidemic, are determined by humidity and rainfall. The humidity is high, the number of days of rainfall is long, and there is a serious risk of occurrence and pandemic. Because rice is a high-temperature plant, it encounters abnormally low temperatures during growth and can also reduce disease resistance and cause epidemics. The occurrence of diseases is also related to the type of rice. In general, resistance to indica rice glutinous rice stronger than japonica. But among the various types, the differences among varieties are also significant and can not be generalized. The degree of disease varies greatly. Conditions are not conducive to disease occurs, even if sick, but a few spots on the leaves; little effect on the yield. However, in serious cases, we can make the rice into pieces and die, can not be heading, resulting in no crop particles. Under normal circumstances, leaf spot