随着栽培年限的延长，昆明地区香石竹栽培中的枯萎病害发生日愈严重。本文通过田间调查及病原菌分离、鉴定、田间接种确定香石竹枯萎病的病原菌为立枯丝核菌。并以真菌通用ITS引物对所分离的三株病原菌进行PCR扩增，结果表明扩增片段为750bp，测序后去除引物序列长度为505bp，所分离3株立枯丝核菌的序列完全一致，该序列与马铃薯、西红柿、水稻、棉花立枯丝核菌的同源性在85％以上，表明所分离于香石竹枯萎病的3个病原菌为立枯丝核菌。利用DNAMAN4.0进行系统进化树分析，表明分离菌株与大麦、四季豆、马铃薯、西红柿、水稻、棉花等的立枯丝核菌归为一类，而落叶松、柠檬、青椒、剑兰、苹果、咖啡等的立枯丝核菌为另一类。在前茬作物交配类型无法确定的情况下，前茬作物的致病菌不仅存在交叉感染的可能，同时还可能产生新的变异类型。因此，在香石竹栽培过程中，应尽量避免在前茬作物为遗传学上相对较近的作物栽培土壤中种植。

This article determine pathogen in carnation which grows in Kunming is Rhizoctonia solani, after field investigation and sampling, indoor isolation, identification, separation of strain field and rDNA appraisal in separate strains. And compare with homology sequence, the results showed that the homology of different host regulatory bacteria homology, homology of minimum and maximum 98%, for 52%. From the homology analysis and the comprehensive analysis of the evolutionary tree, Rhizoctonia solani as a wider range of host pathogenic bacteria, its genome in the evolutionary process of mutation, relative mutual infection. Therefore, in the process of cultivation carnation, we should avoid planting crops in which genetics is relatively close before crop.