关键词: 紫皮石斛, 茎腐病, 层出镰刀菌, 形态特征, 系统发育

Abstract: Objective: To isolate and identify the pathogen of stem rot in Dendrobium devonianum. Methods: Diseased tissues of D.
devonianum were collected, and the pathogen was isolated and purified using tissue isolation method. Colony morphological
characteristics were observed, Koch's postulates were fulfilled to verify pathogenicity, and the pathogen was identified based on
morphological characteristics combined with phylogenetic tree constructed using rDNA-ITS sequences. Results: Typical symptoms of
stem rot in D. devonianum included water-soaked spots, leaf chlorosis, wilting, and defoliation, ultimately leading to plant death. The
isolated pathogen was identified as Fusarium proliferatum, and the symptoms of artificially inoculated plants were consistent with those
observed in the field. Morphological and molecular analyses showed that strain ZB-84 was highly consistent with F. proliferatum, and
phylogenetic analysis supported its close genetic relationship with this species. Conclusion: This is the first report identifying F.
proliferatum as the pathogen of stem rot in D. devonianum. The findings provide new insights for the development of stem rot control
strategies, and lay a foundation for further studies on the pathogenic mechanism of the pathogen and the development of specific control
technologies.

Key words: Dendrobium devonianum, stem rot, Fusarium proliferatum, morphological characteristics, phylogeny