Incidence and Occurrence Pattern of Viruses in Lilies (Lilium spp.) on Jeju Island

To investigate the incidence status of lily viruses on Jeju island, lily samples were collected from 2015 to 2018 and examined for virus infection using reverse transcription polymerase chain reaction. Of the viral infections, mixed and single infections were 70.0% and 17.9%, respectively. The incidence of mixed infections was highest for Plantago asiatica mosaic virus (PIAMV) and Lily symptomless virus (LSV) as 43.4% in 2015; PlAMV, LSV 33.1% in 2016; LSV, Lily mottle virus (LMoV) 10.2% in 2017; and PlAMV, LSV, LMoV and Cucumber mosaic virus (CMV) 15.8% in 2018. The incidence of PlAMV was observed to be 82.0% in 2015, 49.4% in 2016, 13.6% in 2017, and 39.5% in 2018 after the first occurrence of PlAMV in 2013. No symptoms were observed for single infection with LSV. However, in the case of mixed infection with LSV and LMoV, mosaic and leaf malformation symptoms appeared. With mixed infection with LSV and CMV, pale brown necrotic spots appeared, and mosaic and leaf curling were induced. PlAMV was more common in mixed infection than in single infection, and caused necrosis following the development of reddish-brown spots. PlAMV significantly decreased the marketability of lilies owing to the generation of leaf anomalies and curls, and its symptoms were more severe in mixed infections.