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一、病害的发病条件、症状识别及其防治1.水稻恶苗病(徒长病):育秧棚温度在30℃~35℃,催芽过长,播种过密有利于水稻恶苗病发生。播种带菌种子,偏施氮肥,秧苗伤口多的地块发病重。苗期至抽穗期均可发生。被害秧苗呈黄绿色,植株细长,叶片和叶鞘狭长,病重植株长到22~25厘米时即枯死,轻者节间明显伸长,剑叶叶片开张角度大,下部茎节倒生许多不定根,后期茎秆上着生淡红色霉层植株不分蘖,不抽穗。剖开病茎有白色丝状菌丝体。防治措施:⑴农业防治:选用无病良种;合理施用氮肥,培育壮苗,
First, the incidence of disease conditions, symptom identification and prevention 1. Rice Bakground disease (leggy): nursery shed temperature at 30 ℃ ~ 35 ℃, germination is too long, sowing too close to the occurrence of rice Bakanae disease. Sowing contaminated seeds, partial nitrogen fertilizer, seedling wounds and more plots of disease. Seedling to heading stage can occur. Seedlings were yellow-green seedlings, slender plants, leaves and sheaths long and narrow, sick plants grow to 22 to 25 cm long when the dead, the light was internode elongation, the flag leaf blade opening angle, the lower part of the adventitious root regurgitation , The late stalk on the living plants of young moldy tillering, not heading. Cut open stem has white filamentous mycelium. Control measures: ⑴ agricultural control: the selection of disease-free elite; rational use of nitrogen fertilizer, nurturing strong seedlings,