向日葵霜霉病属鞭毛菌亚门,霜霉日,盘根菌属的真菌。在内蒙地区的主要寄主是向日葵,但也为害其它菊科作物。一.症状成株受害后,叶背有白色霜霉,叶片正面有淡绿色的病斑,并逐渐转为黄色至黄褐色。病斑扩大常受叶脉限制而成多角形。 Sunflower downy mildew is flagellin sub-door, downy mildew, fungus fungi. The main host in Inner Mongolia is sunflower, but it also harms other Asteraceae crops. I. Symptoms After adult victims, the leaves have white downy mildew on the leaves, and the leaves have pale green spots on the front and gradually turn yellow to yellowish brown. Lesions are often limited by the expansion of the veins polygonal.