HLVd: Could Hop Latent Viroid be Affecting Your Yields and Potency?

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There are many pests and pathogens that can affect cannabis and hemp crops, but there’s a recently discovered plant virus of particular concern for commercial growers due to its role in decreasing yields and potency: It’s called HLVd. 

Hop latent viroid (HLVd) is a single-stranded, circular infectious ribonucleic acid (RNA) that can infect both hop and cannabis plants due to their close relationship in the family Cannabaceae. The plant virus is completely dependent on its host plant’s metabolism for replication and very difficult to diagnose visually. It lives off of the metabolic system of its host plant and slowly degrades its quality. Cannabis plants infected with HLVd can produce up to 50% fewer cannabinoids, and are often smaller and more susceptible to other diseases such as bud rot. Thankfully, it is not dangerous to humans, but it is obviously detrimental to cannabis crops as well as low-THC hemp.

The pathogen, first identified in 2018 amid the rise of commercial cannabis production, is currently estimated to infect up to 50% of plants in North America. It’s a concern for cultivation facilities of all sizes.

When HLVd is present in cannabis, it does not kill the plants, but it’s damaging with its impact on cannabinoid potency and yield. If found during pre-harvest or post-harvest testing, it will not fail standard measures of compliance; however, it will keep the plants from achieving the level of quality most growers strive to reach. And even if it is dormant, it can still spread across grows to infect additional plants.

While regular lab testing is the only sure way to know if HLVd is affecting a cultivation facility’s operations, there are some signs to look for:

• Reduced height of plants
• Lower trichome and resin production
• Smaller leaf sizes
• Thin or brittle stems
• Small or loose buds
• Malformed stems or leaves

Once a plant has been infected with HLVd, it is impossible to remove the disease completely. And while there’s no way to eradicate HLVd, having quality management protocols in place and practicing good facility hygiene to avoid cross-contamination can help contain the spread. 

Trichome Analytical Testing For HLVd

There are two sample collection methods that Trichome Analytical uses when testing for HLVd. If we receive root material, only a small amount is needed for accurate testing. Samples should be about ¼ inch of the top of the root and come from four different locations on the root structure for each plant that is to be tested. 

Cannabis leaves can also be used to test for HLVd. Samples should be from older growth where the viral load will be higher. We recommend four to six old-growth leaves from different locations across each plant to be tested. 

While either testing method is effective, we find root testing to be the best option for successful confirmation, especially if the HLVd is dormant. We suggest testing mother plants every four to six weeks to make sure they are not contaminating an entire grow. Additionally, any new plants should be tested before they are brought into any cultivation facility. This will help prevent issues like the HLVd spreading to more sensitive cultivars.

Integrating Regular HLVd Testing

The importance of regular monitoring for HLVd cannot be overstated. Without testing, the plant virus can make its way through a cannabis grow, with the potential to severely devalue the entire operation.
Interested in learning more about HLVd testing or any of the other cannabis testing services that Trichome Analytical performs? Reach out to us today.