西瓜幼苗遇阴雨天气突然倒伏,可能是“幼苗猝倒病”,是由一种潜伏在土壤中的藻状菌侵害引起。病症特点是:苗期在根茎部呈水浸状病斑,接着病部变黄褐色而干枯收缩,子叶尚未凋萎,幼苗猝倒。病害发展很快,有时幼苗外观与健苗无异,但接近地面处倒伏,明显缢缩。一般阴湿天气,特别苗 Watermelon seedling suddenly fell in case of rainy weather, may be “seedling damping off disease” is caused by a kind of algae lurking in the soil. Symptoms are characterized by: seedling stage in the rhizome was flooded lesion, then sick yellowish brown and dry shrinkage, cotyledons have not wilted, seedling cataplexy. Disease development is rapid, and sometimes the seedling appearance and health seedlings is no different, but near the ground lodging, constriction. General wet weather, special seedlings