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稻瘟病是水稻一种主要病害。全省稻区每年都有不同程度的发生,特别是水稻生长后期的穗颈瘟发生面积的扩大,常造成较重的减产。因此,做好稻瘟病防治工作已成为夺取水稻高产重要技术措施之一。稻瘟病菌以分生孢子和菌丝体在患病的茎、叶和种子上越冬。在秧田后期温湿度较高的条件下,往往引起苗瘟病的发生和危害。丹东地区叶瘟一般始见于六月下旬和七月上旬。七月中下旬水稻生长进入分蘖盛期和末期时,正逢雨季,是叶瘟病发生盛期。同时,在病斑部产生大量孢子,借空气传播,引起节稻瘟、穗颈瘟、枝梗瘟和粒稻瘟病的发生。八月上、中旬,当水稻抽穗时,若遇到连续低温(20℃以下超过6天,或连续高温(27℃以上),相对湿度大于90％,日照不足,会引起穗颈瘟的大发生。造成穗颈和枝梗枯死,形成秕粒和白穗。
Rice blast is one of the main diseases of rice. The rice provinces in the province have varying degrees of occurrence every year, especially the expansion of panicle blast occurred in the late rice growing season, often resulting in heavy yield reduction. Therefore, the prevention and control of rice blast has become one of the important technical measures to seize the high yield of rice. Magnaporthe grisea winters with conidia and mycelia on diseased stems, leaves and seeds. In late seedling temperature and humidity conditions, often lead to the occurrence of blast and damage. Dandong area leaf plague generally began in late June and early July. Late in mid-July rice growth into tillering peak and end, coincides with the rainy season, is the peak of the occurrence of leaf blast. At the same time, a large number of spores produced in the lesion, airborne, causing section blast, panicle blast, branch blast and grain blast occurred. In mid-August, when rice is heading, if it encounters continuous low temperature (more than 6 days below 20 ℃, continuous high temperature (above 27 ℃) and relative humidity above 90%, lack of sunshine will cause large-scale occurrence of panicle blast Causes panicle neck and branch stems to die, forming panicles and white spikes.