# Cymbidium mosaic virus
**Cymbidium mosaic virus** (CymMV) is a plant virus in the genus *[Potexvirus](https://www.edgepedia.org/potexvirus)* (family Alphaflexiviridae) that infects orchids and is one of the two most prevalent and economically important viruses of cultivated orchids worldwide, together with Odontoglossum ringspot virus (ORSV).[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) In the NCBI taxonomy its current name is Cymbidium mosaic virus, equivalent to [Cymbidium](https://www.edgepedia.org/cymbidium) mosaic potexvirus, with the species name *Potexvirus cymbidii* (taxonomy ID 12178).[2](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=12178&mode=Info)
| Key fact | Detail |
|---|---|
| Classification | Genus *Potexvirus*, family Alphaflexiviridae, order Tymovirales; species *Potexvirus cymbidii*[2](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=12178&mode=Info) |
| First record | Found infecting *Cymbidium* orchids in California, USA, in 1950; described by Jensen (1951)[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) • [3](https://dpvweb.net/dpv/showdpv/?dpvno=27) |
| Genome | Positive-sense, single-stranded, monopartite RNA of about 6,200 nucleotides with five open reading frames and a 3' poly-A tail; complete isolates range from 6,196 to 6,227 nt[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) |
| Virion | Flexuous filamentous rod, approximately 500 nm long and 15 nm wide[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) |
| Transmission | Mechanical spread through sap, mainly on contaminated hands and cutting tools; no known vector, and not considered seed- or insect-transmitted[3](https://dpvweb.net/dpv/showdpv/?dpvno=27) • [1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) |
| Host range | Many orchid genera (Dendrobium, Epidendrum, Laelia, Oncidium, Phalaenopsis, Vanda, Zygopetalum, Vanilla, and others) plus non-orchid hosts including *Nicotiana benthamiana* and *Datura stramonium*[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) |
| Control | No proven method removes the virus from an adult plant; management relies on detection, sanitation, and virus-free propagation material[4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses) |
## History and distribution
The disease was first reported on *Cymbidium* in California in 1950, and the virus was described by Jensen in 1951.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) • [3](https://dpvweb.net/dpv/showdpv/?dpvno=27) Early names included orchid mosaic virus and cymbidium black streak virus.[3](https://dpvweb.net/dpv/showdpv/?dpvno=27) Since then CymMV has been found infecting orchids globally, with recorded occurrences in Singapore, China, India, Taiwan, Malaysia, the United States, Japan, and Korea.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) The first complete genome sequence came from a Singapore isolate.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
## Symptoms
Infection produces either asymptomatic plants or a range of symptoms that are broadly similar across orchid species regardless of location: mosaic patterns on leaves, sunken chlorotic or necrotic patches on leaves and stems, flower deformities and color breaking, and reduced growth (dwarfing).[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) In older leaves the disease typically appears as small, elongated pale areas that may develop into dead, dark spots or streaks; mottling of young leaves can become inconspicuous in old leaves, and Cymbidium flowers rarely display viral symptoms.[5](https://ipm.ucanr.edu/agriculture/floriculture-and-ornamental-nurseries/cymbidium-orchid/) • [4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses)
Symptoms alone cannot confirm infection. Expression varies with the plant's genotype, environmental conditions such as temperature and humidity, nutrition and stress, and the virus species and isolate; some symptoms overlap with other causes, such as flower necrosis from the fungus *Botrytis cinerea*, and infected plants may show no symptoms at all.[4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses) [Asymptomatic](https://www.edgepedia.org/asymptomatic) carriers are also a route by which the virus spreads through a collection.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
## Genome and diversity
The CymMV genome is a capped, polyadenylated, positive-sense single-stranded RNA of roughly 6,200 nucleotides containing five open reading frames flanked by untranslated regions.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) • [6](https://www.sciencedirect.com/topics/immunology-and-microbiology/cymbidium) ORF1 encodes a 160-kDa [RNA-dependent RNA polymerase](https://www.edgepedia.org/rna-dependent-rna-polymerase); ORF2, ORF3, and ORF4 overlap and form the triple gene block, encoding movement proteins TGB1 (26 kDa), TGB2 (13 kDa), and TGB3 (10 kDa), with TGB1 also suppressing RNA silencing; ORF5 encodes the 24-kDa coat protein, which participates in cell-to-cell movement and viral encapsidation.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
Isolates are genetically uniform. The RdRp gene shows about 97 to 98 percent sequence similarity among isolates, and the coat protein about 85 to 100 percent; comparisons across geographic origins show more than 90 percent identity at both nucleotide and amino acid levels.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) Phylogenetic analyses divide isolates into two subgroups, A and B, but the variation does not correspond to geography, likely because extensive international movement and exchange of orchid varieties has mixed isolates worldwide.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
## Transmission and epidemiology
CymMV spreads efficiently without any known insect vector, by mechanical means: sap carried on hands, cutting tools, and contaminated surfaces during propagation, flower cutting, and repotting.[3](https://dpvweb.net/dpv/showdpv/?dpvno=27) • [4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses) The virus is not considered seed-transmitted, and although one study suggested that prolonged insect exposure to infected plants could eventually spread the virus, mechanical transmission is the only natural route established.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) Once a plant is infected it remains infected for life, because the virus is propagated along with the plant's tissues.[5](https://ipm.ucanr.edu/agriculture/floriculture-and-ornamental-nurseries/cymbidium-orchid/)
CymMV and ORSV can co-infect the same plant, and mixed infections are associated with synergism that produces more conspicuous disease than either virus alone.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) In surveys, CymMV is consistently more common in orchid populations than ORSV.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
## Detection
Because symptoms are unreliable, laboratory detection underpins control. Enzyme-linked immunosorbent assay (ELISA) was developed for rapid screening of large sample sets, and immunocapture RT-PCR (IC-RT-PCR), which detects both viral nucleic acid and [capsid protein](https://www.edgepedia.org/capsid-protein), is more sensitive than ELISA by 10 to 100-fold and can detect the virus from dilutions equivalent to 100 ng of orchid material.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) RT-PCR is widely used in research laboratories as a reliable, cost-effective procedure requiring only a small amount of template nucleic acid and no antibodies.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) Other available methods include multiplex RT-PCR for simultaneous detection of CymMV and ORSV in one sample, TaqMan real-time RT-PCR, RT-LAMP, electron microscopy, DIG-labeled cRNA probes, and mass spectrometry.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/) Commercial immunochromatographic test strips are also used by growers for on-the-spot testing.[4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses)
## Management
There are no proven methods for removing virus from adult plants, so management is preventive: isolate or destroy infected plants, disinfect or flame-sterilize cutting tools between plants, wear gloves when repotting, and maintain virus-free propagation stock.[4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses) • [5](https://ipm.ucanr.edu/agriculture/floriculture-and-ornamental-nurseries/cymbidium-orchid/) Virus-free mericlones (virus-free plant clones grown from meristem tissue culture) can be produced in tissue culture in some cases, and research on elimination methods, including cryotherapy, continues.[4](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses) • [7](https://www.casb.org.cn/EN/10.11924/j.issn.1000-6850.casb18120069) Current research also explores transgenic orchids with viral resistance, such as coat protein-mediated silencing, and the possible protective role of the symbiosis between orchids and arbuscular mycorrhizal fungi.[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
## References
1. [Mohamad Yusop, M. S., Mohamed-Hussein, Z.-A., Ramzi, A. B., & Bunawan, H. (2022). Cymbidium Mosaic Virus Infecting Orchids: What, How, and What Next? Iranian Journal of Biotechnology 20(1):e3020.](https://pmc.ncbi.nlm.nih.gov/articles/PMC9284244/)
2. [NCBI Taxonomy Browser: Cymbidium mosaic virus (Taxonomy ID 12178)](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=12178&mode=Info)
3. [Descriptions of Plant Viruses No. 27: Cymbidium mosaic virus](https://dpvweb.net/dpv/showdpv/?dpvno=27)
4. [American Orchid Society: Viruses (orchid pests and diseases)](https://www.aos.org/orchid-care/orchid-pests-and-diseases/viruses)
5. [UC Statewide IPM Program: Cymbidium Orchid, Floriculture and Ornamental Nurseries Pest Management Guidelines](https://ipm.ucanr.edu/agriculture/floriculture-and-ornamental-nurseries/cymbidium-orchid/)
6. [ScienceDirect Topics: Cymbidium (Cymbidium mosaic virus section)](https://www.sciencedirect.com/topics/immunology-and-microbiology/cymbidium)
7. [Wang, R. & Li, J. (2020). Cymbidium mosaic virus and Odontoglossum ringspot virus: Research Progress on Detection Techniques and Virus Elimination. Chinese Agricultural Science Bulletin 36(11):56-62.](https://www.casb.org.cn/EN/10.11924/j.issn.1000-6850.casb18120069)
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*Topic: Encyclopedia › Life and health › Microorganisms and fungi › Viruses and acellular agents › Viruses of plants, fungi, protists, and other non-animal hosts › Plant virus genera › Potexvirus, Carlavirus, and related flexuous-rod genera*
*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license