The occurrence and distribution of viruses infecting Lanzhou lily in northwest, China

Field surveys were conducted during 2015-16 to document the occurrence of multiple virus infections and to record predominant viruses infecting Lanzhou lily (Lilium davidii var. unicolor) in the major area of cultivation, northwest China. Specimens were randomly collected from crops in eight different regions and tested for Lily symptomless virus (LSV), Cucumber mosaic virus (CMV) and Lily mottle virus (LMoV) using a quadruplex RT-PCR assay. Results indicated a high level of LSV (98.2%), a high level of CMV (42.5%), and a low level of LMoV (1.5%). In addition, a high level of mixed infections of LSV + CMV was confirmed in Lanzhou lily; in Huangyu, north Yuzhong and Yongjing, incidence of mixed infections of LSV + CMV occurred in over 50% of plants. Interestingly, 99% of CMV-infected plants were in combination with LSV. The sequence homology of LMoV isolate from this study (GenBank: MF781080) was similar to that previously reported in this region from Lilium oriental. Approaches to disease control using improved virus detection methods are also discussed.