Abstract
Chrysanthemum morifolium Ramat. is a major ornamental crop that suffers from diverse fungal, bacterial, viral, and insect pests, causing significant yield and quality losses. Between 2015 and 2025, rapid progress in molecular biology, genomics, and ecological regulation has advanced both fundamental research and applied control strategies. Multi-locus sequencing, multiplex PCR, and next-generation sequencing refined the identification of fungal and bacterial pathogens, while functional studies of WRKY, MYB, and NAC transcription factors revealed key resistance modules. Hormone-mediated signaling pathways, particularly those of salicylic acid, jasmonic acid, and abscisic acid, were shown to play central roles in host defense. Despite these advances, durable genetic resistance against bacterial pathogens and broad-spectrum defense against viruses remains limited. Novel technologies, including virus-free propagation, RNA interference, and spray-induced gene silencing, have shown promising outcomes. For insect pests, studies clarified the damage and virus-vectoring roles of aphids and thrips, and resistance traits linked to trichomes, terpenoids, and lignin have been identified. Biocontrol agents such as Trichoderma spp., Bacillus spp., predatory mites, and entomopathogenic fungi have also demonstrated efficacy. Future efforts should integrate molecular breeding, genome editing, RNA-based tools, and microbiome management to achieve sustainable chrysanthemum protection.