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Hop latent viroid (HLVd), Lettuce Chlorosis Virus (LCV) and Cannabis Cryptic Virus (CanCV) in Cannabis

Cultivation of cannabis plants (Cannabis sativa L., marijuana) has taken place worldwide for centuries. Recently, in some countries, we have seen the legalization of cannabis for the medical and recreational markets, sparking interest in large-scale cultivation. This increase in production has seen an increase in the incidence and severity of plant pathogens causing several diseases.

Hop latent viroid (HLVd) is a single-stranded, circular infectious RNA that is dependent on its host plant’s metabolism for replication. HLVd infection occurs worldwide in hops (Humulus lupulus) but it can also infect the cannabis plant. The HLVd-infected plants don’t show obvious symptoms of infection but instead grow shorter with smaller leaves, which reduce the production of certain cultivars. It has been estimated that cannabis plants infected with HLVd had half the cannabinoid content of healthy plants and overall yield was reduced 30%.

Lettuce Chlorosis Virus (LCV) is a single-stranded RNA, which is usually found in some plants host such as lettuce, cannabis and hemp plants. The young LCV-infected plants don’t show obvious symptoms of infection until a few weeks. After that, the infection doesn't kill the plants, but their yield is significantly affected. The plant will produce smaller flowers, brittle, yellowish and sometimes necrotic.

Cannabis Cryptic Virus (CanCV) is a double-stranded RNA virus and infects plant species of the Cannabaceae. The effects of CanCV on its hosts are not yet well understood, and it is frequently found in asymptomatic plants.


Pathogen Spread

The spread of plant pathogens is a critical component of disease development, allowing inoculum to be disseminated from one plant to another or from one location or region to another. In indoor growing environments, the introduction of diseased plant materials as cuttings or stock plants can result in the spread of pathogens.

These virus is usually spread via infected tools or through cloning (cuttings taken from an infected mother).


How to detect HLVd, LCV and CanCV- Cannabis and Hemp Plant Pathogens?

As described before, symptoms of HLVd, LCV and CanCV are not always obvious in the vegetative stage, asymptomatic or appeared a few weeks after infection. So the prevention is the key to reduce the pathogen spread in the cultivar.

This can be ensured through testing of stock plants for the presence of pathogens prior to vegetative cuttings being taken, disinfesting seeds and equipment to eradicate pathogens.
Methods for testing of plants to ensure they and the planting materials are free from pathogens are widely available and several commercial laboratories can provide detection services.
Screening regularly by Real Time PCR is the key to isolating the infected plants from their growing area.

The Cannabis mother plants should be tested by Real time PCR before taking any cuttings to ensure they are virus-free and because symptoms of the virus are not always obvious in the vegetative stage screening regularly by PCR is the key to isolating the infected plants from their growing area and the incoming clones.


If you are looking for a Real Time PCR Kit to detect Cannabis and Hemp Plant Pathogens, please check our kits:
RT - Real Time PCR Detection Test Kit Supreme HLVd (Hop Latent Viroid)
RT - Real Time PCR Detection Test Kit Supreme HLVd / LCV / CanCV