【摘要】 <正> 尖孢镰刀菌是土壤中常见的一种镰刀菌,能寄生于多种植物,导致植株萎蔫,也能较长期地腐生于土中,其中的萎蔫专化型是棉花枯萎病的致病菌,在连续栽种感病棉花品种的情况下,该菌每年随病株残体进入土壤后土中菌量随之增多,因而病情逐年加重,即使更多还原

【Abstract】 This article deals with the saprophytic colonization of F. oxysporum on plant residues in relation to its survival in soil. Most of the plant residues, such as the straws of wheat, rice, bean, cotton, milk vetch, etc., are easily colonized by F. oxysporum in soil under dry farming, even if those have been colonized previously by Chaetomium, Mucor, Aspergillus, Bhizoctonia, Sordatia and other soil fungi.The temperature and soil moisture adapted to saprophytic colonization ranged from 15°—30℃ and 20—80% of moisture holding capacity respectively. Fungal growth was suppressed in submerged soil due to lack of oxygen, while colonization still occurred on residues floated above the water.Propagule density of the pathogen in heavily infested soil decreased sharply under flooding condition, but it could not be entirely eliminated from flooded rice growing soil. It existed in the oxidation layer and propagated gradully as saprophytes or parasites after 1 or 2 successive cotton croppings. When fresh organic matter was added into the soil under flooding condition, the pathogen diminished with the decline of soil Eh.更多还原