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近年来全国各玉米产区,由于丝黑穗病的蔓延危害,玉米减产甚巨。北方17个省、市、自治区的67个县(旗)统计,平均发病率(相当于损失率)6.2％,最高达93.4％。1977年
In recent years, all maize producing areas across the country have suffered huge losses due to the spread of smut. Statistics from 67 counties in 17 provinces, municipalities and autonomous regions in the north show that the average incidence (equivalent to the loss rate) is 6.2% and the highest is 93.4%. 1977