Combatting a Cannabis Menace: Hop Latent Viroid

By Lee Allen
Published: April 28, 2022 | Last updated: April 28, 2022 05:36:01
Key Takeaways

Hop Latent Viroid (HpLVd) can quickly wipe out an entire population of cannabis plants. Fortunately there is a doctor in the house, as Lee Allen explains.

Source: Rachel Weill and Dark Heart

Once the plant has this viroid — an infectious entity smaller than a virus — you can’t really do anything to heal it. At least that was the previous thinking involving Hop Latent Viroid (HpLVd) and its detrimental effect on legal cannabis crops.


“Hop Latent Viroid is perhaps the greatest threat to the legal cannabis industry,” says Dr. Bryce Falk, Emeritus Professor at the University of California Davis plant pathology department. “It’s very difficult for growers to identify due to its latency and it spreads undetected within a grow, wiping out much of the commercial value.”

Wiping out commercial value to the estimated tune of billions of dollars in losses as shown through testing over a three-year period among more than 100 California cannabis growers where more than a third of the tests from 90 percent of the cultivation sites proved positive for HpLVd. Extrapolating those West Coast grower numbers to all U.S. growers does not bode well.


Dark Heart Industries, a California cannabis genetics company, completed 200,000 tissue tests for the menace which they ultimately identified as the cause of dudding in cannabis, resulting in reductions in yield and potency, stunting, loss of vigor, and changes in morphology.

Geneticist Dr. Jeremy Warren, Dark Heart’s plant science and laboratory director, was the first scientist to put the responsibility of loss on HpLVd and come up with a cleaning process to eliminate it from infected specimens.


Once the plant has the viroid, it’s hard to clear it out and you can’t really do much to heal it.

Company publicity proudly proclaims — “Our top-notch scientists made us the first and only company to identify and cure the hop latent viroid. Solving this critical issue in cannabis health instantly helped customers gain a 30 percent improvement in crop yield and secured us as the top innovator within the cannabis agricultural-tech space.”


“Once the plant has the viroid, it’s hard to clear it out and you can’t really do much to heal it,” Dr. Warren says. He likens it to a major, debilitating disease in humans that requires a massive response.

“Use chemotherapy for cancer as an analogy. We take positive plants and torture them for a month to reduce the viral load, just like doctors do to their human cancer patients — you torture all the cells to hopefully kill the cancerous ones.

“If a special or a proprietary strain is fully infected, like the entire grow or Mother Block, then eradication via tissue culture is the only way to clear that strain,” he adds. “The tissue culture process utilizes a proprietary treatment that eliminates the viroid and leaves a healthy, rejuvenated strain.”

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As the producer of nearly 10 percent of all legally grown cannabis plants in California, Dark Heart expects the patent-pending viral removal process application (slowed down by the COVID crisis) to be completed soon.

“Hop Latent Viroid infection impacts legal cannabis crops nationwide, not just in California,” says Dark Heart founder and CEO Dan Grace. “Our new Davis laboratory facility for biotechnology research and innovation will greatly expand our capacity to process viroid assays to support growers and other laboratory facilities across the country.”

And that’s good news for the U.S. growers and their optimistic forecast for 2021 with anticipated production of more than seven million pounds of legal cannabis resulting in sales expected to surpass $40 billion.

“For cannabis to achieve its potential as a commercial agricultural crop, the industry needs this type of large-scale testing and treatment platform,” says Dr. Falk.

photos by Rachel Weill and Dark Heart


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Written by Lee Allen | Writer, Reporter, Gardener

Profile Picture of Lee Allen

Lee Allen is an award-winning reporter of both electronic and print media. He is also a struggling backyard gardener.

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