Infectious Pathogen Silently Spreads To Over 90% Of California's Cannabis Farms, Destroying THC Production

A hop-latent viroid (HLVd), an infectious pathogen, is devastating cannabis farms in California by infiltrating plants and ruining entire crops just before they’re ready for harvest.

By causing a 30% reduction in plant weight, HLVd destroys THC production, clearly a devastating financial loss for growers. First identified in 2019, it has since infected around 90% of California's cannabis crops, posing a global threat to the entire industry.

To combat the spread of HLVd, a Bay Area startup Purple City Labs, reports SFGATE, has developed an on-site test that claims to deliver results within hours. The test is thought to surpass current methods that involve sending samples to labs and then waiting days or weeks. By swiftly identifying infected plants, this testing approach could help slow the pathogen's spread, says Luke Horst, director of business development for Purple City Genetics. 

“We didn’t just identify a great test that is accurate, but it’s [also] easy to use and it doesn’t require a high level of expertise,” said Horst. “You can take microbiology to the public and put it in their hands. … It’s important for people to have this type of testing.”  Delayed Symptoms Affect 'Mother Plant, Pathogen Silently Spreads

HLVd has been silently spreading on cannabis farms for over a decade, wrote SFGATE, initially perplexing growers who couldn't figure out why their harvests were declining. 

The viroid's late-acting symptoms, known as "dudding," distort the plants and significantly reduce THC production. This is particularly problematic for modern cannabis farming practices, where hundreds of new plants are propagated from a single, artificially prevented flowering "mother" plant. The delayed symptoms allow infected mother plants to silently spread the pathogen for months without ever showing signs of the disease. Hence, a faster onsite test for the plants. 

“By the time you get the results back, you may have cut that plant and sold it to your customers. So there is a real need for a high throughput onsite diagnostic test for hop-latent viroid,” said Ali Bektaş, CEO of Purple City Labs and a lead author in the 2019 HLVd identification papers. 

Leveraging his Ph.D. in microbial ecology, Bektaş developed a LAMP test for HLVd. LAMP is a molecular test that uses real-time loop-mediated amplification (LAMP) technology to detect the presence of SARS-CoV-2, the virus that causes COVID-19, so Bektaş thought it could also work on this new viral threat to cannabis. And it does, with results in just a few hours.

Purple City Labs is now selling the technology globally at $10 per test. Bektaş recently demonstrated the product in Spain, where HLVd was detected in the first test conducted.