# Viroid

> The smallest known plant pathogen: a short circular RNA, usually 246-401 nucleotides, with no protein coat and no protein-coding genes, copied by the host's own enzymes.

- Canonical: https://genetixbay.com/knowledge/glossary/viroid.html
- Also written: viroids, Pospiviroidae, infectious RNA
- Glossary category: Pests and diseases · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

A viroid is an infectious, single-stranded circular RNA molecule, usually about 246-401 nucleotides long, that causes disease in plants. Unlike a [virus](https://genetixbay.com/knowledge/glossary/plant-virus.md) it has no protein coat and does not code for any proteins. It relies entirely on host enzymes to copy itself, and disrupts the plant's [gene](https://genetixbay.com/knowledge/glossary/gene.md) regulation as it does. The best-known example in cannabis is [hop latent viroid](https://genetixbay.com/knowledge/glossary/hop-latent-viroid.md) (HLVd).

## In practice

Viroids are very stable and spread mainly mechanically: on cutting tools, hands, grafts and propagation material, and in some cases via seed or pollen. Common alcohol wipes are not reliable against them; growers use disinfectants with documented [efficacy](https://genetixbay.com/knowledge/glossary/photon-efficacy.md), such as diluted [sodium](https://genetixbay.com/knowledge/glossary/sodium.md) [hypochlorite](https://genetixbay.com/knowledge/glossary/free-chlorine.md) (bleach) solutions, between plants. Viroids cannot be treated with any spray. Testing by RT-PCR and discarding infected stock are the only reliable controls, with [tissue culture](https://genetixbay.com/knowledge/glossary/tissue-culture.md) to recover clean lines.

## Don't confuse with

- **Plant virus**: has a protein coat and genes; often spread by insects.
- **Prion**: a misfolded protein in animals, nothing to do with plants.
- **Bacteria**: living cells that can be cultured; viroids cannot.

## Related terms

[Hop latent viroid](https://genetixbay.com/knowledge/glossary/hop-latent-viroid.md), [Plant virus](https://genetixbay.com/knowledge/glossary/plant-virus.md), [Sanitation](https://genetixbay.com/knowledge/glossary/sanitation.md), [Quarantine](https://genetixbay.com/knowledge/glossary/quarantine.md)

## Read more

- [Hop latent viroid (HLVd, 'dudding') and other cannabis viruses](https://genetixbay.com/knowledge/diseases/hop-latent-viroid-and-viruses.md)

## Sources

1. Adkar-Purushothama CR, Sano T, Perreault J-P, 2023. Hop latent viroid: a hidden threat to the cannabis industry. Viruses 15(3):681. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10053334/
2. PNW Plant Disease Management Handbook. Hemp (Cannabis sativa) - Viroid Diseases. https://pnwhandbooks.org/plantdisease/host-disease/hemp-cannabis-sativa-viroid-diseases