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1 病害症状病初叶片产生褐色带有轮纹的圆斑,中心部位有黑色霉层。严重时病斑互相联合使整个叶片枯焦。由于气候条件,烟叶成熟度等因素的影响,症状会有许多变化。如多雨潮湿时很适合病害的扩展蔓延,病斑边缘为浸润状;气候干燥时病斑小,边缘深褐色,无轮纹;只有干、湿气候相间出现时,病斑上才形成轮纹。 2.病害发生和流行原因赤星病是由一种寄生性很弱的真菌引起的病害,条件十分有利才引起流
1 disease symptoms Early leaves produce brown with circular pattern of round spots, the central black mold layer. Serious lesions combined with each other so that the entire leaves Kujiao. Due to climatic conditions, tobacco maturity and other factors, there will be many changes in symptoms. Such as wet and humid is very suitable for the expansion of disease spread, the edge of the lesion is infiltrated; dry spot when the disease is small, edge dark brown, no wheel pattern; only dry and wet climate appears when the lesions on the formation of round lines. 2. Disease occurrence and epidemic reasons Brown spot disease is a disease caused by a very weak parasitic fungus, the conditions are very favorable to cause flow