October 1, 2021

Viruses have had a profound effect on human history.  Researchers work tirelessly every day uncovering how to better combat viruses that affect not only humans and animals, but plants as well.

The Hop Latent Viroid (HpLVd), a single-stranded, circular infectious RNA, runs rampant in the hemp and cannabis industry, causing the plants to drop dramatically in efficacy when harvested.

HpLVd does not kill the plant, and much like viruses in humans and animals, is often found to be asymptomatic in Cannabis sativa.[1] However, its effect on plant potency is detrimental. Plants infected with HpLVd may have half the cannabinoid content of their healthy counterparts.[2]


Where Did Hop Latent Viroid (HpLVd) Originate?

Hop Latent Viroid (HpLVd) was first identified in hops.[3] Initially, it was difficult to detect as hop plants are almost always asymptomatic during a HpLVd infection, allowing the virus to spread quickly.

As mentioned before, Cannabis infected with HpLVd may or may not manifest any apparent symptoms but understanding what those symptoms can be is important to the understanding of how to combat this virus.


Common Symptoms of HpLVd in Cannabis Sativa

Also known by the less formal term ‘dudding,’ HpLVd can cause physical symptoms in Cannabis sativa such as stunted growth, a brittle stem, or noticeable malformation of the leaves. [4]

This may cause cannabis plants to grow shorter with smaller leaves and stunted buds that have far fewer trichomes.   On top of these physical symptoms, a daunting element is found in its name: Hop Latent Viroid. The virus can remain latent or inactive within infected plants, making it nearly impossible to detect without testing.

All of these factors contribute to lack of potency and decreased harvest weight.  It has been determined that plants infected with HpLVd may have half the cannabinoid content of their healthy counterparts and have smaller flowers.[5] When these affected plants go undetected and then are utilized in cannabis and hemp CBD products, the lack of potency is evident.


Controlling The Spread Through Testing

Because HpLVd is a rather new virus, discovered in California in 2017, its characteristics made it rather difficult to identify. Coupled with its asymptomatic nature that allows mass spreading to occur, it has been discovered that most of the spreading of HpLVd can be tied to transmission via mechanical means (tools such as pruning shears) rather than physical contact or proximity between individual plants.[6]

Thankfully, with research done since the discovery of HpLVd, we now have some answers and the ability to test. Green Leaf Lab is delighted to provide testing for HpLVd.

Green Leaf Lab employs state-of-the-art PCR instrumentation to provide accurate HpLVd screening services to our customers. In doing so, we can alert our customers that they have a HpLVd outbreak amongst their stock. Not only does catching the virus at the beginning stages of growth help ensure successful harvest, it is a low-cost way to prevent a much larger loss of revenue due to diminished potency or reduced harvest weight.


Prevention Is Best

As with most plant pathogens, prevention before infection is even more important than simply identifying infection.

Because the virus spreads from mechanical cross contamination, we as an analytical testing laboratory suggest good equipment sanitation practices to combat the spread of HpLVd and other plant pathogens. For instance, use fresh gloves each time you handle a new plant and be sure to sterilize tools in between plants.

There is still much to be learned when it comes to the transmission and progression of HpLVd in cannabis and hemp, but much like many breakthroughs in hemp CBD and cannabis testing, Green Leaf Labs is dedicated to be part of these progressive transformations in the industry.


[1] https://apsjournals.apsnet.org/doi/10.1094/PDIS-03-19-0530-PDN

[2] https://darkheartnursery.com/news/hop-latent-viroid/

[3] https://academic.oup.com/nar/article-abstract/16/10/4197/2378130?redirectedFrom=fulltext

[4] https://apsjournals.apsnet.org/doi/full/10.1094/PDIS-03-19-0459-PDN

[5] https://darkheartnursery.com/news/hop-latent-viroid/

[6] https://apsjournals.apsnet.org/doi/10.1094/PDIS-03-19-0530-PDN


cbecbenhaNCIAStarburstacclcbe logoWomen's Business Enterprise certifiedWorldwide Certified Business Review Board verified