在北方棉区，大田棉花黄萎病造成的产量主体损失是由重病株以上级别病株所致。形成重病株以上级别病株的根源，主要是苗期黄萎病菌的侵染。无论是在中肥田或高肥田，第一次发病高峰期形成的发病株率和发病程度远高于第二次发病高峰期，即第一次发病高峰期形成的重病株以上级别病株是构成棉花产量损失的主要来源。 In the northern cotton area, the main yield loss caused by the cotton field wilt disease is caused by the above diseased plants. The formation of severe disease above the level of strains of the root causes, mainly the infection of Verticillium dahliae. Whether in the fertilizer field or high fertility field, the incidence of the first incidence peak incidence rate and incidence of disease is much higher than the second peak incidence, that is the first peak of the incidence of severe disease above the level of diseased plants constitute The main source of loss of cotton production.