甜菜黑斑病在黑龙江甜菜产区普遍发生,为害程度日趋严重,1988年调查个别地块发病率达30％以上。其危害不亚于甜菜褐斑病,该病多发生在甜菜生长繁茂期(7、8月),抗病力差的老龄叶片上,严重时也侵染中龄叶片。初期形成的病斑与褐斑病相似,二者混合发生时,更难区分。病斑边缘清晰有时可见轮纹,为圆形或椭圆形,直径在3—8毫米。后期病斑变薄,一般不破裂、不腐烂。老 Beet black spot disease occurred in the sugar beet producing areas in Heilongjiang Province, the degree of damage is more serious, in 1988 the incidence of individual plots surveyed more than 30%. Its harm no less than the sugar beet leaf spot disease, the disease occurs in the sugar beet growth period (July, August), poor resistance to aging leaves, severe infection of middle-aged leaves. The initial formation of spots and brown spot similar to the two mix occurs more difficult to distinguish. The edge of the lesion is clearly visible at times with round lines, round or oval, 3-8 mm in diameter. Late lesions thinning, generally do not break, do not rot. old