What is the Hop Latent Viroid?

The hop latent viroid (HpLVd) is an infectious pathogen that causes disease in cannabis plants. Also known as “dudding” or “dudding disease,” plants infected with HpLVd may or may not show symptoms (symptomatic vs asymptomatic). HpLVd was also previously known as PCIA (putative cannabis infectious agent) until Dark Heart confirmed HpLVd as the cause of PCIA in 2018. HpLVd has been detected throughout the United States and Canada.

HpLVd can be dormant in a plant for extended periods of time before showing symptoms. Symptoms include reduced vigor, abnormal branching, stunted trichome production, reduced potency, and an overall loss of quality and yield.

Why Should Growers Care?

If left untreated, HpLVD can seriously reduce a crop’s potency and yield. Every garden tested in 2019 was infected with HpLVd. Most gardens had an infection rate of about 25-50%, causing an estimated 44 million dollars in losses per year.  HpLVd infections typically occur when an infected clone or plant is introduced into a healthy garden, where it spreads to other plants.


How is it spread?

Research about transmission methods is ongoing. The viroid can spread through different types of contact, such as mechanical transmission. This occurs when pruning tools are used on an infected plant, then on an uninfected plant. HpLVd can also be transmitted through the seed of an infected plant, though more research is underway to determine the transmission rate.

The latent nature of HpLVd makes it a challenging pathogen to detect and fully eradicate. A common scenario in an infected garden is that while plants look healthy, they are in fact asymptomatic and don’t exhibit symptoms. As a result, many growers are not aware that the pathogen is present and spreading to other plants in the garden.


What can be done?

The first step is determining if HpLVd is present in a garden. Not all infected plants will “look” infected or show symptoms. A diagnostic screening test is the fastest way to determine the presence of the viroid. If a positive result is found, the infected plant should be removed from the facility immediately and disposed of. Any plants that it was touching should also be quarantined and tested.

If a special or a proprietary strain is fully infected (such as the entire grow or mother block), then eradication via tissue culture is the only way to clear HpLVd from that strain. The tissue culture process utilizes a proprietary treatment that eliminates the viroid and leaves you with a healthy rejuvenated strain.

Click here to learn more about HpLVd screening and services from Dark Heart. Also download the free Hop Latent Viroid white paper. It includes preventative measures, best practices and SOPs, and more.

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