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1 为害特点 该病发生于缓秧后至分蘖前期。植株表现生长缓慢,分蘖发生迟而少,老叶上密布赤红色小点,发病严重的有缩苗症状。一般在高温多雨季节症状自然消失。它的主要为害是降低有效分蘖期分蘖数,易造成亩茎数不足。2 发病原因 水稻赤枯病是多种不利因素交互作用的结果。生产上常见的加重发病的不利因素有以下几方面。2.1 盐碱危害2.1.1 耕地过浅,犁底层加厚;或耙地过细,破坏了土壤结构;或排水不良,地下水
1 damage characteristics The disease occurs after the slow seedling tillering stage. Slow growth of plant performance, late tillers occur less, the old leaves are densely reddish brown spots, severe symptoms of shrinking seedlings. Usually in high temperature and rainy season symptoms disappear naturally. Its main damage is to reduce the effective tillering tiller number, easily lead to mu shortage of stems. 2 The cause of the disease Rice red blight is the result of a variety of adverse factors interaction. Adverse factors in the production of common diseases are the following aspects. 2.1 Saline hazards 2.1.1 Cultivated land too shallow, thick plow floor; or rake too thin, destroyed the soil structure; or poor drainage, groundwater