一、苗期病害是全苗壮苗的主要障碍我国各主要棉区在四、五月正当棉花播种出苗期间,常有轻重不同的低温期。棉苗初期抗逆力较弱,一遇到低温阴雨,就会出现大批烂种、病苗和死苗。历年以来各个棉区苗期病害是普遍而严重的;苗期病害成了全苗壮苗的主要障碍。例如,山东省苗期发病率一般都是30—50%;1956年全省发病棉田达800万亩。江浙棉区苗期发病率为 First, the seedling disease is the main obstacle to seedlings Zhuang Miao China’s major cotton areas in April and May, when cotton sowing, there are often different low-temperature period. Cotton seedlings early resistance is weak, a cold rain, there will be a large number of rotten, sick and dead seedlings. Over the years since the cotton seedling disease is widespread and serious; seedling disease has become a major obstacle to seedlings. For example, the incidence of seedling in Shandong Province is generally 30 - 50%; 1956 cotton disease in the province reached 800 million mu. Jiangsu and Zhejiang cotton seedling incidence rate is