Understanding Hop Latent Viroid: A Threat to Cannabis Cultivation

In recent years, a silent yet devastating pathogen named Hop Latent Viroid (HLVd), also referred to as HLV or HpLVd, has emerged as a significant threat to the cannabis industry. Originating from hops, this viroid has found its way into cannabis cultivations, causing a myriad of problems for growers and the industry at large.

What is Hop Latent Viroid (HLVd)?

Hop Latent Viroid is an infectious plant pathogen that targets cannabis plants, causing a disease commonly known as “dudding disease” or just “dudding.” Unlike viruses, viroids are smaller pathogens composed of a single-stranded RNA molecule that uses host plant enzymes to replicate. HLVd can remain latent or inactive within infected plants, making detection without molecular testing almost impossible.

The Impact on Cannabis Industry

The presence of HLV in cannabis plants can be devastating. It’s known to cause stunting, chlorosis, leaf deformation, brittle stems, reduced flower mass and trichome number, significantly altering the typical plant morphology. Once a plant is infected, there’s no eliminating the viroid, which makes it a persistent problem for growers. The viroid’s ability to stay dormant until triggered by stress factors further complicates the issue, often leading to significant losses across cannabis grows.

Studies have revealed that HLV has already caused considerable damage in North America, with estimates suggesting that about 40% of legally sold cannabis flower in Canada might be carrying HLV. This pathogen is not only a concern for individual cultivators but poses a substantial threat to the cannabis industry’s sustainability and growth.

Testing for HLV in Cannabis

Timely detection is crucial to managing and mitigating the impact of HLVd on cannabis cultivations. Various diagnostic testing methods have been developed to identify the presence of HLV in cannabis plants. For instance, the AmplifyRP XRT for HLVd is a kit designed specifically for testing cannabis against the hop latent viroid. The process involves preparing leaf samples, preparing sample extract pouches, preparing test tubes, preparing reaction pellets, and executing the reaction in a machine known as the AmpliFire. This detailed process allows for the rapid testing and detection of HLV in cannabis plants, enabling growers to separate infected plants from healthy ones and stop the spread of HLV.


The emergence of Hop Latent Viroid in cannabis plants has drawn attention to the importance of continuous monitoring and testing in cannabis cultivations. As the cannabis industry continues to expand, developing effective strategies to manage and mitigate the impact of pathogens like HLV will be crucial in ensuring the industry’s sustainability and growth.

For more information and guidance on HLV in cannabis, check the following resources:

  1. Summit Genetics: Testing Cannabis for the Hop Latent Viroid
  2. What is hop latent viroid in cannabis https://cannabistraininguniversity.com/growing/hop-latent-viroid-in-cannabis/

(Note: The links have been verified and are active as of the date of publication. Please check the links for the most recent and updated information.)