Hop Latent Viroid

Hop Latent Viroid (HLVd) is a plant pathogen that affects cannabis.  It is one of many viroid diseases that infect a wide range of fruits, vegetables, and flowers.  HLVd cannot affect humans, animals, or your pets.  It’s not a human pathogen, so you don’t have to worry about ingesting cannabis flower containing Hop Latent Viroid either.

In 2019, it was discovered that HLVd made the jump from hops to cannabis and was having a negative effect on yields and cannabinoid levels of infected plants.  Anecdotal evidence suggested parent to seed transmission of HLVd, and in spring 2023 Tumi Genomics confirmed this route of transmission with an important experiment.  The experiment showed that either an infected male or an infected female plant will produce seeds that are also infected.  When you plant those seeds, the frequency of seedlings that are infected can be as high as 43%.  Growers are introducing a possible contamination into their tent or facility every time they germinate seeds from infected parents, or from parents they have very little information about.

What are the implications for home growers?  First, you want to start with HLVd-free seeds.  If you’re going to spend all that time, energy, and money on growing cannabis, then your yields and THC levels shouldn’t be negatively affected by this viroid.  We’re also concerned that beginner growers might miss the symptoms of Hop Latent Viroid and get discouraged with growing in general because of the poor results that were beyond their control.  Finally, if you find a ‘keeper’ plant that works for you, or is special in some way, you might not be able to hold onto it because removing HLVd from a cannabis plant costs thousands of dollars.

At Green Rose Seeds, our approach to HLVd is exclusion and eradication.  We strive to exclude the viroid from our breeding stock and we plan to eradicate any HLVd-positive plants we identify (luckily none so far).  We might screen our library for resistant cultivars in the future, but for now we’re just working to test and eliminate Hop Latent Viroid if we find it in our facility.