种子传播和土壤传播的微生物,既有植物区系的,也有动物区系的。它们单独或共同作用时,都可能引起棉花幼苗的复合病害。所涉及的病原大多数是普遍存在的真菌,它们除了与任何地方生长的棉花相结合以外,还与其它许多寄主相结合。病原线虫常与这些真菌结合在一块,这两种微生物共同作用,比起真菌单独作用会引起更严重的病害。当几种微生物同时危害种子和幼苗时,其中每一种病原所产生的效应会相互作用而形成综合病徵。复合病害包括出苗前的种子和幼苗不同程度的腐烂,未出苗前和出苗后的失绿和坏死以及矮化和萎蔫。苗病的发生主要是受不利的温度和土壤湿度的影响。但是,有利于病原的迅速繁殖而少利于 Microorganisms that spread both seeds and soil, both flora and fauna. When used alone or in combination, they may cause complex disease in cotton seedlings. Most of the pathogens involved are ubiquitous fungi that, in addition to being combined with cotton grown anywhere, combine with many other hosts. Pathogenic nematodes are often associated with these fungi, both of which work together to cause more serious diseases than fungi alone. When several microorganisms endanger both seed and seedlings, the effects of each of these pathogens interact to form a comprehensive syndrome. Complex diseases include varying degrees of decay of pre-emergence seeds and seedlings, chlorosis and necrosis of pre-emergence and post-emergence, dwarfing and wilting. Miao disease occurs mainly due to unfavorable temperature and soil moisture. However, conducive to the rapid propagation of pathogens and less conducive