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Bio Security - Hop latent viroid (HpLVd)

JJ the Gardener

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Bio Security - Hop latent viroid (HpLVd)





Hemp and Cannabis Bio-Security (HpLVd)

I always found growing like being a sea captain.  Which I know nothing about really but my point is this.  In growing it is your job to bring to harvest quality and yield and a good part of nature is against you.  To be an effective grower you have to know how to navigate those problems just as a sea captain has to learn to read and operate in heavy and unfriendly waters to the calmest.

The HLVd (Hop latent viroid) in growing is like hearing an old sea captain talk about a rogue wave.  While rare it happens and I will explain to the best of my understanding on how to navigate this issue from the home grower to the professionals.

Bio Security is a relatively new term that integrates pest management to include the life cycles of the pest, mold/mildew and viruses together into a single topic.  It should be stated that I am writing this from the perspective of best practice. 

  • I personally believe that transmission of this virus is mostly done through mechanical use most typical of clones and seconded lower potential by seed germination/transmission and insect feeding.  
  • I have read for and against academic papers and studies but the results of those working on the front lines such as those at nurseries and grow operations are why I tend to believe this is largely spready by mechanical means. 
    • I find this true more for those who operate with strict SOP's and professional operationalism.
    • I find pest infection more of a potential for smaller more amateur grows operations to the home grower setups that are not operating by strict SOP's which have a higher potential to have poor environments and infestations compared to professional styled growers.  
      • It is within this area of growers that I have the largest concern.
  • Due to this conflict I have written from a best practice point of view and I cannot with certainly that I agree 100% percent it is wholly mechanical based and not by some smaller measure of pest infection in the right conditions which would affect home growers who is in part a larger part of my pointed audience.

This is likely already part of a current security plan but for newer growers and managers this information may have more value however I recommend that currently skilled and knowledged growers still refresh this material as to ensure your security protocols and latest understandings are effectively up to date.

So while some of this information and topics may be common knowledge to you I suggest the method by which these bio pest and virus interact may further justify a more stringent overall security plan that addresses those individual aspects into one program that strengthens the security and safety of the grow operation.  

  • If you find that I am preaching to the choir.  I would value any additional input that you would be willing to share.  It is in community that solutions are truly found and all genuine contributions are highly respected.

I have read some great writings on these viruses but most are written in the interest of laboratories and not of independent scientific or academic writings. I have read many academic writings regarding the virus issues and one can find for and against some treatments and vectors.

  • Most of the academic and scientific papers and studies are in the hops and hemp field but cannabis has also been affected. 

It is currently at the point I cannot say with 100% certainty if some or all of this information is wholly factual as this area seems to have only recently received larger attention and study. 

  • Due to this I may or may not alter some of this writing as more understanding and knowledge is gained as developments unfold.  Due to this, if you have interest. 
    • I would subscribe to this post as I will keep it updated as applicable.
  • As with all my writings, this is an opinion that I based the science and reasoning that I have found applicable and applied that as my basis for this writing.   

Due to this I may alter my bio-security writing and recommendations. However, even if true, we would want to potentially implement the same bio-security measures for other reasoning with the same level of importance or close to it to justify any additional expenses and efforts. 

The justifications of some of the issues could change but that would not diminish the importance of other connected justifications for the security protocols.


  1. Virus information and identification.
  2. Understanding the Viroid
  3. Infected Plant Protocols
  4. Testing
  5. Treatment
  6. Generic Preventative Plans



HLVd (Hop latent viroid) information and identification.

The following affects Cannabis and Hemp.  While there are other viruses that can potentially affect cannabis and hemp these are the two that that have most potential and likelihood of seeing at some point in your career. 

  • In the 20 years of my growing I have never seen a virus but operating procedures were far different back then compared to the relaxed settings and general protocols of today. 

In the operating atmosphere of prohibition the necessary operating procedures naturally worked against such issues but in todays environment those safeguards currently are eroding and should not easily be confident in without gaining an understanding of these viruses and implementing preventative measurements and correct treatment protocols when and if identified.

Depending on the size and seriousness of your operation, the level of preventative management increases but this is in tandem with due diligence.


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).
    • This is one of the parts that makes this viroid very difficult to remove.


It has the following capabilities.

  • To infect mechanically such as using the same blade between clones.
    • Can continue in seed form.
  • To lie dormant.  Just when you think you got it out of your grow area and you have testing that verifies it is not present in the plants, it shows up.
  • To activate at any time during the plants life cycle.
  • Will diminish and plant quality and likely yield.
  • Can be Asymptomatic.
    • This means it can show no signs and the plant be 100% healthy and correct.
    • It can infect others.
    • It can turn on at a later time period.
    • Potentially can show negative in testing.
    • It can be active in one section or the plant or a branch and not in another section or another branch showing negative.


Symptoms include:

  • reduced vigor,
  • abnormal branching,
  • stunted trichome production,
  • reduced potency,
  • and an overall loss of quality and yield.


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.


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.
    • Most commonly through trimming and cloning from plant to plant.


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.
  • I personally believe that transmission of this virus is mostly done through mechanical use most typically via clones and trimming and seconded and at a lower potential by seed germination/transmission and insect feeding.  
    • I believe stressed plants such as plants living under poor plant conditions and a stressful environment with infected plants and heavy infestation that the percentage of insect transmission strengthens greatly. 


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.


Videos explaining the virus.

This is an excellent video describing the HLVd Virus.  We are not affiliated with them.  Please support them direct.  

AAUvwniy5jPTkQdC7GRDf2ts53B2mp3xd-fSfLPQ Mushroom Cowboy


This is an excellent video that will generally discuss this well.  We are not affiliated with them in anyway, please support them directly at - https://www.youtube.com/channel/UCFACkeFHeEww8m0bt5Ug7ZQ

AAUvwnhQhtJPFIuodH4IKOokk1_81ZWS6q0k_d2H Future Cannabis Project - Please support them directly, we have no affiliation.




What to do once you suspect infection.

The first step is determining if HpLVd is present in your grow operation.  This is not as simple as it would seem.  It is like looking for needles in a haystack.  We know the visible ones but some are hiding and we need to find them.

  • Initial identification and/or notice of an issue.
    • Visually is typically how most growers will first notice this viroid.
      • Growers will begin notice differences in the growth and an overall slow down in the plants development.
        • The leaf and growth will look different as well.
          • Leaves can look stunted to witches broom like.
          • Dramatic reduction to loss of terpenes.
          • Dramatic reduction in trichrome development.
          • A golden appearance on the top of the plant, referred to as golden head.
      • Not all infected plants will “look” infected or show symptoms.
        • This is the Asymptomatic stage that some go through but they can pass the viroid on and they can turn on to an active state at any time.
        • Identify all clones that come from an infected mother.  If a clone shows an infection, assume the mother is infected and asymptomatic if the mother is not showing signs.
          • Remove all applicable plants.
          • I am comfortable saying you can finish the grow if not at the beginning of the grow as this viroid is typically spread via mechanical processes such as cloning and the trimming of plants.
            • Clean trimming equipment between plants to prevent plant to plant transmission. 
            • In this manner trimming can infect clones of non infected mothers.


Some illustrations.

This video is very good at illustrating differences in quality and on the crop but it is only available at Youtube:  https://www.youtube.com/watch?v=Y2_e9_TDfHM


Pics - These pics are from Ripper Seeds, we have no affiliation but they illustrate excellent photos.  Please support Ripper Seeds directly.  https://www.ripperseeds.com/en/



  • Notice the severely stunted growth from the new growth area of the plant.
    • This virus affects new growth dramatically and directly impacts yield, quality and finishing times.



  • Notice how the growth hits the stress marks.  The stems changed color and growth slows and shortens in size.
  • If allowed to mature it will take longer and have significant and quality reductions.



  • Notice how you can see the growth that affects the side limbs.
  • Smaller growth and weaker stems.
  • Helps mold/mildew to better take hold with thinner and weaker cell walls to penetrate.
  • Easier for pest to attack.



  • Notice how the whole crop is affected and it is does not appear to have been had leaves removed.
  • A forest of plants susceptible to other and further infections from pest to fungi.
  • This crops quality has been compromised.


Save A Grow Update 4 and Hop Latent Viroid Video - We have no affiliation with this video maker.  Please support him direct at: https://www.youtube.com/channel/UCdfDnqy2aM41aGllYSEg9FA

AAUvwni26wv8diG0X-yJnGkxheWQ54p1_wclzlsA medicropper

  •  Around the 2100 mark he will talk about the viroid.  I believe this is how most people will come to a similar conclusion.


  • Testing and treatment - Updated to include information regarding Chlorine Dioxide.
    • Unless you can afford the lab work to treat the genetic it is not a viable solution to try to save infected genetics.
      • 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.

        • A diagnostic screening test is the fastest way to determine the presence of the viroid.

        • The tissue culture process utilizes a proprietary treatment that eliminates the viroid and leaves you with a healthy rejuvenated strain.

      • Some branches can show clean and others can show infected in testing.
        • Due to this we need to take 4 samples in a regular circular pattern at various heights from low, middle and upper branches. 
          • Approximately 12 testing points per plant.
            • As I stated, this is best practice recommendations.  It is up to you to find an effective compromise depending on your operational budget.
            • Ensure that even and consistency is in selecting locations and choices.
              • This can be seen as a costly step but it is of most important to ensure the viroid does not slip through this net.
              • With those who have cant lose genetics, it is an option to use the services of a well qualified tissue culture laboratory.
                • Essentially plant material is taken from the meristem as these plant cells typically grow faster than the viroid can replicate so any viroid or virus is more diluted in the sample.
                • They then heat and cold treat this plant material as to ensure any viroid present is ideally destroyed.
                • Then through tissue culture the plant is remade and should be in a revitalized and healthy state.
                • This is costly and takes approximately 6 months.
    • Chlorine Dioxide  - I have seen via video and pictures from very trusted friends who are testing/working with infected plant stock with Chlorine Dioxide.
      • currently this is in early stages but some positive work has been seen.  Lots of work to do but exciting to see this information and is a wonderful xmas present as we all could use some good news in 2020!
      • I can see the value of dispersing Chlorine Dioxide via uptake and via foliar feeding.
        • Give first treatment to a thirsty plant.
          • The idea is that the plant being thirsty will uptake more treated waters and gain an effective strong start against the viroid.
          • Clones
            • Soak new cut clones and seeds in Chlorine Dioxide before transplanting/planting.
            • Mist with Chlorine Dioxide
            • Clean all tools with Chlorine Dioxide
          • Foliar use in between the feeding/treatment cycles.  
            • Do not foliar feed prior if you are making the plant thirsty to increase volume of uptake.
          • Examples of home or small grower use water preparation.

Aquamira Drops - Chlorine Dioxide - The Outdoor Gear Review

AAUvwnidjExJ-0pqU_bDwFA6V5bCqVhSfN19YwwE TheOutdoorGearReview

Lifesystems Chlorine Dioxide Tablets



  • Here is are some current use of Chlorine Dioxide in irrigation and municipality water. 
    • There are lots for and against of the safety of Chlorine Dioxide but I find that this system for cleaning public water and in plant irrigation is a matter of proven safety as far as my opinion goes.


Chlorine dioxide for pathogen control in irrigation

Stabilized chlorine dioxide (Oxine ®) for horticulture

AAUvwnhitMuSHdig4y41MVC6jYnM94UphQPkka4N Clean WateR3


AAUvwnhitMuSHdig4y41MVC6jYnM94UphQPkka4N Clean WateR3

Chlorine Dioxide in Municipal Drinking Systems

AAUvwnjTRfeX3syMmVY_5vHyIv_IOH-6OsbeQxfm Scotmas Group


I believe that the Chlorine Dioxide is very promising in this viroid dilemma and I am excited to see how developments go.  Prevention and effective operating protocols and standards are key and Chlorine Dioxide potentially plays a role in both.

At the very least.  I recommend understanding Chlorine Dioxide more and potentially how it may or may not fit into your growing operations.

Safety information regarding CLo2 - Chlorine Dioxide Awareness Training

AAUvwnikf6wfTgQwytcC2BtXe3mBDI0YezJsCEzSConvergence Training by Vector Solutions


Limitations of Chlorine Dioxide



Actions to take:

  • Quarantine and/or remove and discard identified plants 
  • At the end of the grow, discontinue all effected and potentially affected plants to include mothers.
    • All plants from infected mother.
    • Remove clones derived from an infected mother.
    • Remove mother.
    • Remove any seed made from infected parents.
    • Remove any plants from seed derived from infected plants.
      • If using soil or media infected with insects.
        • Consider disposing of the soil if you have had insect issues where they have a life cycle in the media.
          • This is due to concern that media living insects could potentially infect the plants.
            • Currently I can find no documentation to back this recommendation up but I add it in due to best practice aspects.
              • I personally believe that the virus is potentially spread via insect in a perfect storm of worse case scenarios such as high humidity, insects that travel from plant to plant which still may hold the virus in wetness on its feeding apparatus rather than intern life cycle within the insect or in an  transmission from internal fluids during feeding.
                • I base this opinion on the understanding that infestations do not appear to be significant spreaders of this disease in well managed growing operations.
    • Contact everyone who received a clone and or seeds from infected plants and infected from the line of plants.
      • Ask that any seed sellers to contact their clients for those affected.
      • Ask any clone sellers contact their clients for those affected.
      • While doing this is costly, it will work more in your favor in the future than any short term benefit by not contacting and making right once you can.


  • Selecting new stock/genetics.  When selecting new genetics depending on your operating budget and level of seriousness I present the following recommendations.
    • Try to purchase seeds from certified clean parents.
      • At this time I am unaware of this being a thing but if your a large grow operation and use seed, ask for this.
      • Ask for this and try to find breeders that take this viroid seriously.
      • Consider older more reliable strains than newer strains.
        • This is due to older stock being clean but they can still be subject to the viroid but risk factor is smaller I believe.
    • When buying clones.  Try to find clones from certified clean mothers.
      • At this time I am not aware of this being a thing but ask for it.
      • Select from vendors and nurseries that take the viroid seriously.
      • Try to look at customer reviews that match your time line.
    • Quarantine/Label/Mark all brought in genetics. 
      • Grow as you normally would.
        • At any sign of viroid,
          • Test for it and/or start over if certain or when positive test is certified.
      • As you make your selections, pending no sign of the viroid within the grow than you can consider the grow operation clean.
        • To verify that, have the selected mothers tested and certified clean.


  • Standard Operating Procedure recommendations.
    1. Create standards that include for the effective cleaning of equipment between plants and/or for equipment sets for each plant or section.
      • This is easier said than done and a major pain the butt factor I understand but also is dealing with this viroid.  Mechanical transmission is the number one spreader of this viroid.  
      • I recommend making equipment sets and/or for the cleaning for each plant or section of plants.
        • Sheers,
        • Cloning equipment
        • Any piece of mechanical equipment that would be used from plant to plant
    2. Implement any applicable preventive measures for insects, mold and mildew.
    3. Implement any Environmental improvements as applicable.
    4. Work to increase and stabilize Brix levels in the plants.
      • This helps keep an eye on the health of the plants quality.
        • Stabilization is key as this can be a tell tell sign of something more seriousness going on with the plant and that the plant is functioning well depending when and if it destabilizes..
          • Always check brix at the same time of the day.


I hope this write helps you.  This is not something to take lightly as its effects are darn right scary.  Sorta like a corona virus/Aids for plants.  Personally I know of growers who lost very prized genetics due to this and their cries were so loud in the force that I heard it. 


Credits - We have no affiliation with those in the credits.  Please support them directly.  They have our highest respects.  If anyone is missed, please contact us and we will fix.  It is only due to an error if a credit is missing.




A Cultural Healing and Life writing  ~JJ the Gardener





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  • JJ the Gardener changed the title to Bio Security - Hop latent viroid (HpLVd)
  • 2 weeks later...
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Current Chlorine Dioxide Use


Some independent workings going on in Spain using Chlorine Dioxide to clean a plant of this viroid.

  • It is being administered via foliar spray.  Records are being kept and pending on the outcome more detailed information will be given.
  • Thus far it appears to be working but it will take some time.
  • The infected plant is a mother and is a set of clones.
  • A positive lab test for the viroid was indicated for the mothers.  Once it is felt the viroid is clean, a new lab test will be done to prove or disprove the viroid's removal or if it remains.

I will keep this updated as I get more information.  Thank you.

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  • 2 weeks later...
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got an update, sorry no pics at this time from our friends fighting the good fight.

The infected mother plant is progressing positively and a clone did root from the mother.  While only one clone compared to many the clones is not a good ratio but the material used was not ideal.

Positive steps forward and as this clone grows and has the mother improves we hope to achieve true positive results by using Chlorine Dioxide.  CL02

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