猝倒病是冬瓜苗期的常见病害,在早春育苗中,常引起大片的幼苗死亡,导致毁苗重播。 1 症状 该病主要危害幼苗。种子出土前发病,造成烂种;幼苗期发病,主要是茎基部产生水渍状暗色病斑,绕茎发展1周时,茎细胞组织腐烂,缢缩成为线状,迅速倒伏。由于病害发展迅速,幼苗叶片仍为绿色时,病苗即可猝倒。病害扩展蔓延迅速,往往引起成片幼苗倒伏。在高温高湿的条件下,病苗表面及附近床土生有稀疏的白色菌丝。 2 发病条件 猝倒病为真菌病害,由鞭毛菌亚门腐霉属真菌侵染致病。病菌以卵孢子在土中越冬,可在土中长期 Damp down disease is a common disease in winter melon seedlings, nursery in early spring, often cause large pieces of seedlings died, leading to the destruction seedlings replay. 1 Symptoms The disease harms seedlings. Seed germination before the disease, resulting in rotten seedlings; seedling incidence, mainly stem base produces water-like dark spots, about 1 week around the stem development, stem cell tissue decay, shrink into a linear, rapidly lodging. Due to rapid disease development, seedling leaves are still green, the vaccine can be catapulted. Spread of disease spread rapidly, often lead to lodging of film seedlings. Under the condition of high temperature and high humidity, sparse white mycelium is born on the bed surface and in the vicinity of the sick seedling. 2 conditions Damp down disease is a fungal disease conditions, caused by Flammulina fungus Phytophthora infestation pathogenic. Pathogens to oospores in the soil over the winter, can be long-term in the soil