Incidence of Cymbidium mosaic virus and Odontoglossum ringspot virus in Dendrobium spp. in Thailand

Dendrobium is the most popular cut flower and potted plant for the Thai orchid industry and several viruses have been reported to negatively impact upon their growth and yield. This study was carried out to confirm viral infection and identify the viruses infecting Dendrobium spp. in Thailand. Dendrobium orchids propagated through cutting of pseudobulbs, and grown in tissue culture were screened for Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) with indirect enzyme-linked immunosorbent assay (ELISA). CymMV and ORSV were detected in 65.4% and 0% of the 280 tested plants, respectively. Among the 29 cultivars of tissue cultured cut flower and 19 cultivars of potted Dendrobium, CymMV infection rates were 18.6% and 8.7%, respectively. No CymMV or ORSV were found in 21 species of in vitro seed cultured seedlings of Thai native Dendrobium. The data indicated that CymMV is a prevalent virus in vegetatively propagated Dendrobium but not in in vitro seed cultured seedlings in Thailand. Plant material must be tested for the presence of viruses before being used for mass production by tissue culture, and sanitation during propagation of orchid plants and harvesting of flowers is essential in order to prevent the virus from spreading.