幼苗猝倒病普遍发生于苗圃中，是苗圃的第一大病害。尤其在培育松、杉苗时，必须把防治猝例病放在头等地位。一、病原与病害症状１种芽腐烂型。即播种后至幼苗出土前，病菌侵染种子或幼芽，使种、芽的组织腐烂。通常成堆发生。在地面则表现为缺苗、断垄或缺行。种子未经催芽、? Seedling damping-off disease occurs in nurseries, is the largest nursery disease. Especially in the cultivation of pine, fir seedlings, prevention and treatment of disease must be placed on the first position. First, the pathogen and disease symptoms 1 bud rot type. That is, sowing seedlings to sowing before the germ infection of seeds or sprouts, so that species, bud tissue decay. Usually piles occur. On the ground is manifested as lack of seedlings, broken ridge or lack of practice. Seeds without germination?