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一、黑胫病病菌首先侵染根或茎基部则形成黑胫(病斑褐色),黑胫从近地面的茎部开始向上扩展蔓延,最后包围全茎。叶片感病后呈水渍状暗绿色斑块,扩大后中央呈黑褐色圆形大斑,可见明显边缘,隐约有轮纹。根部腐烂呈黑褐色,植株最后枯死。防治办法:农业防治,选用抗病品种,实行3年以上轮作,注意田间起垄开沟排水,及时清除病株和病叶;药剂防治,每亩用70％敌克松350克兑干土15～20公斤拌匀,在移栽时施入烟株穴中或施入烟株四周,施药后立即覆土,以免降低药性。也可每亩用50％瑞毒霉100～150克兑水浇灌。二、青枯病烟株感病后,先是烟株半边叶片发生枯萎;中后期,全株叶片枯萎;横切病茎或叶茎部,可
First, blackleg pathogen first infects the base of the root or stem to form a black shin (spot brown). The black shank spreads upward from the stem near the ground and finally surrounds the entire stem. After the leaves were infected with water-like dark green patches, after the enlargement of the dark brown round central spot, visible edge, there are vaguely round pattern. Root decay was dark brown, the last dead plants. Prevention and treatment methods: agricultural prevention and control, the use of resistant varieties, the implementation of more than 3 years of rotation, pay attention to field ditching ditch drainage, timely removal of diseased plants and diseased leaves; drug control, with 70% ~ 20 kg mix well, when applied in tobacco plant transplanting point or around the tobacco plant, immediately after application of soil cover, so as not to reduce the drug resistance. Can also use 50% per acre Rubisco 100 to 150 grams of watered water. Second, the wilt disease Sick tobacco flu, the first tobacco plant withered half of the leaves; in the late, the whole plant withered leaves; cross-sick stem or leaf stem may