Incidence and Detection of Three Viruses (Cucumber Mosaic Virus, Lily Mottle Virus, and Tobacco Rattle Virus) in Daylily Plants Cultivated in Korea

Daylilies (Hemerocallis spp.) are native to Northeast Asia, including Korea, China, and Japan, and are now widely cultivated as ornamental plants. This study investigated the occurrence of viruses in daylily cultivars at the National Arboretum in Pocheon. A total of 312 leaf samples from 104 cultivars showing virus-like symptoms were collected and analyzed using reverse transcription-polymerase chain reaction and nucleotide sequencing. Three viruses (cucumber mosaic virus [CMV], lily mottle virus [LMoV], and tobacco rattle virus [TRV]) were detected in this study. Of the 312 samples, CMV, LMoV, and TRV were detected in 10 (3.2%), 67 (21.5%), and five (1.6%) samples, respectively. Mixed infections were observed in seven cultivars, with all three viruses detected in three of them. A total of 46 viral isolates were sequenced and deposited to GenBank. Phylogenetic analysis revealed that the isolates were closely related to previously reported isolates from Korea, China, and the United States but formed distinct clades, suggesting host- or region-specific diversification. This is the first report of CMV, LMoV, and TRV infection in daylilies in Korea, providing valuable molecular data for future virus management and disease prevention strategies in Hemerocallis cultivation.