A plant-specific pathogenic RNA called Hop Latent Viroid Testing was just found. Since it can infect cannabis, some people in the industry think this may be the main reason for "dud" plants that were hard to explain before.

Here, we'll talk about what this plant disease is, how it spreads, and how to stop it from spreading in your growth operation.

Hop Latent Viroid Testing: A Novel RNA Virus

The story of Hop Latent Viroid Testing, or HLVD, began in California in 2017 when cannabis grower Graham Farrar of Glass House Farms noticed that some of his plants were showing strange symptoms and producing less than usual.

Farrar didn't know why these plants were getting so sick, so he contacted researchers at the University of California Davis, which is known for its strong plant science program and connections to the agricultural industry.

This led to a successful research partnership with Phylos Bioscience, a company in Oregon that tests the genetic makeup of cannabis. Scientists at Phylos looked at the DNA of some of Farrar's sick plants and found a new RNA virus.

The results were published in 2019 in the journal Plant Disease, and another research group from Dark Heart Nursery in Oakland, California, checked them out independently. The new RNA virus was given the name Hop Latent Viroid Testing. RNA viruses, like the SARS-CoV-2 virus that caused COVID-19, use RNA to infect their host instead of DNA, which is how traditional viruses work.

Signs of HLVD in Cannabis

HLVD makes cannabis plants show obvious signs, such as:

• slowing down growth
• Cracked stems
• fewer oil glands and less oil production
• fewer flowers
• leaves that are malformed and/or turn green

Researchers now think that HLVD is probably common among people who grow cannabis all over the country. Due to how recently it was found, though, many growers may not know about it or know what its symptoms are.

Another thing that makes it hard to stop the spread of HLVD is that it likes to sleep. As its name suggests, the virus can stay dormant or inactive in plants that have been infected, with no obvious symptoms.

HLVD’s latency allows it to quietly spread until secondary stress from heat, nutrition, or a pest allows the virus to activate and take hold. This makes it hard to find a new outbreak without testing. Clones made from a single infected mother plant are especially at risk, and researchers think that HLVD may be the cause of clonal dudding that seems to happen at random.

When trying to clone a plant that has been infected, cuttings have a lower chance of taking root. But if the virus stays dormant and the clones grow roots, a stressor in the environment during the growth phase could kill 10–30% of your plants.

Preventive Actions

When it comes to how HLVD is spread and how it gets worse in cannabis, there is still a lot to learn. But it seems that the virus is mostly spread by mechanical means or fomite transmission, which is when a susceptible host touches an object that has the virus on it.

The good news is that this type of disease can't spread if you follow the best practises for cleanliness. Clean all of your tools before you start to spread. A diluted bleach solution may be more effective than alcohol in killing virus particles. Also, think about putting any new varieties you get in quarantine and carefully inspecting them before adding them to the rest of your plant stock.