What is Hop Latent Viroid (HLVd)?
Hop latent viroid (HLVd) is an infectious, RNA pathogen that is completely dependent on its host plant’s metabolism for replication. As the name suggests, HLVd occurs worldwide in hops, but has also been found to affect cannabis.
How does Hop Latent Viroid affect Cannabis and Hemp Plants?
If HLVd is the only pathogen present, it will not likely kill the plant or even cause obvious symptoms of infection before flowering (i.e., curling or yellowing leaves). However plants will show subtle symptoms and be more susceptible to other infections/pathogens.
HLVd can greatly reduce the quality and quantity of the flower the infected plant produces. During the vegetative stage, plants may grow shorter with smaller leaves and tighter node spacing. Flowering plants may have smaller, looser buds with much fewer trichomes. At Pinnacle Analytics Lab, we have found that plants infected with HLVd may have <50% of the cannabinoid content of healthy plants — sometimes as low as 6%.
How can Hop Latent Viroid be Controlled?
Although HLVd can be eliminated from a cannabis or hemp plant via tissue culture, it is a long and laborious process that should only be reserved for cultivars that are critical to your business.
With HLVd, prevention is key. Creating and upholding adequate sanitation procedures will significantly contribute to preventing the spread of HLVd and all other plant pathogens. It is recommended to use fresh gloves and sterile tools each time you handle a plant. If gloves are going to be reused, be sure to sanitize them before touching another plant.
If possible, cultivators should screen their mother plants, via qPCR, before taking cuttings to ensure they will be free of HLVd. It is also recommended that incoming clones be screened to verify infected plants will not be introduced to your grow.