What viruses are found in Cannabis?
By: Bill Drake and Authentic Genetics
Contributions by: Sam the Skunkman
We’ve started hearing from our friends asking us to share what we know about HLVd and how we see it impacting the future of Cannabis cultivation, and of course we’ve been keeping a close eye on plant pathogens of all kinds for many years. We’ve reached out to our Authentic Genetics network to discover what other experienced growers are doing, and we’ve taken a look at the emerging and historical research on HLVd and other plant viroid pathogens of interest.
We’ll divide this article into two parts:
First, the short, simple steps anyone can and should take in the new world of emerging plant viroids. Both experienced growers and HLVd researchers agree that there are some simple, effective defenses against infection by HLVd. Defense is critical because once infection occurs both a complete crop loss and difficulties with subsequent crops are likely.
Second, we’ll take a cruise through the research on HLVd and plant viroid pathogens, revealing a fascinating world that we can’t see and are barely learning to detect, but that we can learn to work with and live with if we come to understand it better.
We have to confess when all this started we thought - “Oh. Another virus.”
Wrong! Not a virus. We’ve had a lot to learn, starting with the fact that Viroids and Viruses are related but not the same forms of life, and many would argue that neither is ‘alive’. Neither have any energy metabolism of their own and both depend on hijacking a cellular organism host in order to survive, replicate, and transmit, each in its own way.
Viruses can invade plant and animal cells while it is thought that viroids are limited to plants. Viroids are ‘naked RNA”, simply molecules, where Viruses have a protein coating that enables them to force host cells to copy them. Viruses appear to act purposefully on the cell’s mechanisms, getting them to replicate the virus, whereas Viroids appear to be molecular messengers of some kind with indeterminate functional ‘purpose’ and appear to be largely pathogenic.
What all this seems to mean for growers is that infection by Viroids will likely be more difficult to mitigate than infection by plant Viruses, which means that prevention is the key.
We hate to oversimplify, but a lot of the things a grower can do immediately to prevent infection by all plant pathogens, not just HLVd, are things we all know already but don’t practice. It’s kind of like brushing your teeth and flossing - if we all did it right every time we would probably have good teeth all our lives. But we don’t, so dentists drive Mercedes. We all know that cleanliness is the key to plant pathogen control, and most of us probably try, but few of us focus and do it right every time, which is precisely how it has to be done or else - as we’ve found out to our severe loss more than once.
So here’s a list of steps that both science & grower experience say if taken at the appropriate time, every time, will greatly decrease your odds of infection by plant virus and viroid pathogens including HLVd, as well as infestation by pathogenic insects, molds, fungi etc.
This is a short starter checklist - please add your own tips in the IG comments section
- Clean your hands and fingernails thoroughly at the beginning or any work session and any time you move from one plant handling task to another
- Wear clean work clothing, not street clothing, use disinfectable gloves and aprons, and have a clean changing room
- Change from street shoes and use a shoe bath
- Practice strict visitor management and don’t allow pets
- No smoking or vaping Cannabis or using e-cigs but especially no Tobacco products
- If you handle cigarettes you could transmit Tobacco Mosaic Virus unless you wash your hands.
- Ditto a pack of cigarettes in your pocket
- There may be differences between cultivars in TMV resistance
- Clean all tools not just cutting tools using strong sterilization procedures
- Don’t worry about corrosion if you use either bleach or TSP - they sterilize on contact and can be washed off quickly.
- Sterilize any pots, trays, tabletops, counters, shelves and containers and wipe down the outside of every bottle or container.
- Use clean water throughout the grow; we rely on multiple well-maintained Reverse Osmosis systems
- Give plants room enough for air movement on all sides; preferably no touching
- Provide clean, filtered air; maintain and vary your positive air pressure; change out filters more often than recommended
- Use seeds of known & trusted origin; maintain your own Mother plants grown from trusted seed and clone only from your own Mothers
- Use only soil/growing media and supplements from trusted suppliers
- Maintain proper humidity & temperature zones
- Become familiar with insect, mold and fungus hiding spots and inspect your plants and surrounding areas - including underneath benches and tables, carefully and often
- Use beneficial insects generously inside and control outside insect entry; if affordable use appropriate beneficial insects like wasps outside your grow to help control the surrounding environment
IF A GROW IS HLVd INFECTED
There are a number of treatments being researched for viroids in both plant tissues and in the environment.
However, if HLVd infection is detected in a high-value Cannabis grow, current best practice says that all the plants should be removed and destroyed, by burning if possible.
Other indoor and greenhouse pathogens like botrytis and PM can be dealt with at grower’s discretion but HLVd requires removal of the infected plants at a minimum and in reality it means removing everything and thoroughly disinfecting the grow.
Good General Greenhouse Sanitizing Procedures
Good review of the best sanitizing agents (we talk more about milk later!)
PART TWO: THE WORLD OF HLVd & PLANT VIROID RESEARCH
This section offers links to some of the most interesting peer-reviewed scientific journal research we’ve been reading that bears on the origins, spread, and control of the Hop Latent Viroid (HLVd), recently identified as one of the drivers for the Dudding pandemic afflicting thousands of Cannabis grows.
To begin your exploration of the world of Cannabis viroids you can’t do any better than this 2020 article by our old friend Rob Clarke.
A FEW THOUGHTS ON “DUDDING” AND HLVd
The “Dudding” phenomenon looks like it may involve far more viroid pathogens than just the recently identified HLVd, as well as a lot of damage caused by non-viroid entities.
For example, we’re pretty sure that a lot of what’s being attributed to HLVd aka Dudding is actually being caused by the Russet Mite.
We’ve seen whole grows devastated by this almost invisible mite that also afflicts CBD and Industrial Hemp crops big time and whose damage is easily classified as “dudding”. (Quick note - Russet Mites are totally preventable by growing from seed, and there are beneficial insect controls available if they arrive on infected clones.)
But back on the matter of viroids, we thought we would share what’s being discovered by scientists about pathogenic and beneficial plant viroids in both Cannabis and its closest relative Hops. The crossing over of HLVd from Hop plants to Cannabis growing as hemp may very well have occurred a long time ago even though it is just emerging, maybe just like so many contemporary human viral diseases seem to be coming out of nowhere. These viruses and viroids haven’t just appeared from nowhere - it looks like they’ve been here a very long time and are somehow just becoming activated.
The research seems pretty clear that damages from these viroid pathogens, especially to indoor Cannabis, are a complex phenomenon and aren’t just limited to the impact of a single viroid pathogen HLVd. Plant Viroids are part of an extended ecosystem of natural biological entities that flow in, around and through Cannabis plants in a greenhouse or field.
Viroids were first identified in 1971, almost 70 years after the discovery of viruses. It took that long because Viroids are so much smaller and more elusive because they are pure RNA without the more detectable protein coating of a virus. HLVd is one of an emerging group of Cannabis microRNA Viroids that are technically pathogens but that seem to have both beneficial and pathogenic roles in Cannabis growth and development. Some interesting current journal science on Cannabis miRNA can be found in the references at the end of this article and also here, here, here and here.
We especially hope you’ll enjoy this science-heavy but very accessibly-written article that points to Viroids as possible, even likely origins of life on Earth after their precursor amino acids, purines and pyrimidines, and carbon compounds survived interstellar temperatures and radiation and arrived here on meteors.
Given that we know that Cannabis evolved THC specifically for trapping UV starlight to protect its seeds, we think the idea of life first arriving on meteors works beautifully. We hope that the idea of a cosmic aspect to what’s happening in our Cannabis grows can help focus the search for a ‘cure’ for HLVd and other Cannabis diseases and invasions using a more integrated approach that might even include questioning things like quality, scale and value in the Cannabis culture.
On the question of transmissibility through Cannabis seeds it looks like the answer will be yes. The microbiome inside the Cannabis seed is full of beneficial forms of life including, if Hops research carries over to Cannabis, a lot of beneficial viroids too, so it shouldn’t surprise us that Cannabis is also host to pathogenic invaders like HLVd. The idea of viroids occurring in and being transmitted through Cannabis seed isn’t that unusual, since bacteria, viruses and fungi also inhabit the interior germplasm of seeds in nature, where they are translocated from an infected mother plant as she creates the germplasm.
More likely what is happening is that a number of viral vectors are converging on Cannabis for many of the same reasons that mono-cropping attracts biological disasters. The convergence of Hops and Cannabis science says clearly that, just like in Hops, transmission through cuttings will occur from infected mother to clone virtually 100% of the time in Cannabis. There’s also research that says it is sometimes possible to avoid cloning infected tissue by taking your cutting from high on the plant (meristem tissue), but the data show that even that approach isn’t foolproof - as do the experiences of a lot of growers.
All of the available science and best practices discovered by growers argues for seed from plants that have been isolated from HLVd for generations. Knowing the origin of your seed, and the seed that the Mother Plant came from for cuttings, gives you the best assurance that all your hard work won’t go for nothing because of something you can’t see or control. As you can see, that’s the current scientific consensus.
We hope that you’ll find some of the science we’ve curated throughout the article is useful in your understanding of Viroid pathogen issues in Cannabis. We also hope that you’re following us on Instagram and that you’ll contribute your own thoughts on Cannabis viroids and their control in the comments section.
ABOUT THE RESEARCH
We would like to share some of the most interesting research we’ve studied while trying to understand this complicated and novel challenge to our Cannabis community. As usual here on Authentic Genetics the research we cite comes largely from peer-reviewed journal articles.
The research we’ll be showing you seems clear to us - while HLVd is primarily spread “mechanically” in hop plants, meaning through contact, like with tools and machinery, or by exchange of fluids or tissues like with handling, cloning and pruning, as well as very likely by sucking insects like aphids, including the Bhang Aphid which we’ll talk about in an upcoming article. HLVd is also apparently transmitted through infected seeds in at least some hop cultivars - we’ll show you that research too.
So given all the other close similarities between Hops and Cannabis, we think that in addition to being spread through clones HLVd is probably being transmitted IN the germplasm of Cannabis seeds, and of course there’s little doubt that HLVd is being transmitted ON cannabis seeds.
So barring research findings to the contrary, it looks like the Hop Latent Viroid spreads primarily through unsafe cloning and handling and a dirty environment, kind of like unsafe sex in high traffic motels spreads STD.
Shower frequently, check the mattress for alien life, and practice safe sex with someone you know and you probably won’t get STD. Avoid recklessly cloning with strange plants in unsafe environments and grow only from trusted seed in a clean room and you probably won’t get, import or spread HLVd.
OK, that’s a little over the top, but we’re trying to make a point worth remembering about cleanliness and Cannabis grows.
The lesson we take away from the hop-related HLVd research is: clone away but always start with a Mother plant grown from known, trusted seed, and then practice safe handling every step of the way. Both of these commitments to quality critical importance now and for the future of both Medical and Adult Use Cannabis.
Some of the research we’re looking at details the impact of HLVd on the biochemistry of the Hops cone, which is in so many fascinating ways biologically parallel to Cannabis flower clusters. It’s especially fascinating to see which of the Hops terpenes are affected by HLVd and how, because Hops terps and Cannabis terps are almost identical. For example, you’ll see that HLVd infection Increases Myrcene production in Hops cones. I can’t pretend to understand the science but the narrative is pretty clear and Cannabis growers may want to look more closely at what’s going on with Hops and terpene production because it’s been studied a lot longer in Hops - for making beer - than it has in Cannabis.
Another parallel perhaps worth noting is that it appears that HLVd has very different effects on Terpene profiles depending on the Hops cultivar, which might also be expected to happen in Cannabis. The fact that some of the terpenes are increased and that the impact on yields varies significantly between Hops cultivars is very interesting. We wonder what the potential could be for modifying Cannabis terpene profiles by modifying their natural beneficial viroid populations - which have yet to be identified because we’ve just been alerted to their apparently vast and complex presence in Cannabis buds by research like this in hops.
This same area of Hops cultivar research also suggests that breeding viroid resistance into selected Cannabis cultivars might be possible. We wonder that since Cannabis and Hops evolved long ago in close proximity in the Himalaya mountains and highlands, perhaps Cannabis cultivars with pure Himalayan genetics might have more of a natural resistance to a viroid from an ancient co-evolving Hops plant that would have threatened their own reproduction - their flowering. Maybe Mother Nature didn’t allow any dudding in the Himalayas a few million years ago? With the right original Himalayan genetics could we find HLVd resistance today?
Some Curated Hops Latent Viroid Research
After browsing the following research, please come back to the Authentic Genetics Instagram website and share what you’ve learned in the comments section.
RESEARCH PAPER #1 - SELECTED EXCERPTS
“The Influence of Hop Latent Viroid (HLVd) Infection on Gene Expression and Secondary Metabolite Contents in Hop ( Humulus lupulus L.) Glandular Trichomes”
“HLVd infection significantly affected the content and composition of secondary metabolites in maturated hop cones of the studied cultivars. The contents of alpha bitter acids and xanthohumol were significantly reduced in the infected hop plants of all the cultivars. The contents of monoterpenes, terpene epoxides, and terpene alcohols were increased, but the contents of sesquiterpenes and terpene ketones were decreased within essential oils in cones of infected Saaz hop plants. For this cultivar, the yield of the dry cones was also significantly reduced for both studied years.”
“Hop secondary metabolites are biosynthesized and accumulated in glandular trichomes, lupulin glands, and on the inner side of cone bracteoles and bracts. In the last two decades, numerous transcriptome and proteome studies have provided a systematic understanding of secondary metabolite biosynthesis pathways and elucidated the role of structural and regulatory genes for bitter acids, essential oils, and prenylated flavonoids biosynthesis in hop.”
“Viroid infection also influences the essential oils composition in hop cones, which contributes to the aroma flavor of beer.
“The increase of myrcene content by 38% for Wye Challenger-infected plants was first reported. Similar results were found for hop cultivars Saaz and Premiant when the content of myrcene was increased by 29% together with monoterpene pinene isomers (about a 40% increase) for infected plants.
On the contrary, all sesquiterpenes were reduced by 4.4% to 29% in cones of infected plants. From other compounds, terpene alcohols (linalool, geraniol, and methylgeranate) and epoxides were increased and ketones were decreased for infected plants.
Therefore, the composition of essential oils in hop cones is genotype-dependent and specific, and these changes cannot be general.
Trends for the content of sesquiterpenes and monoterpenes (myrcene and β-pinene) were similar within Polish hop cultivars, with the exception of myrcene for cultivar Sybilla. The content of linalool was higher for cultivars Sybillla, Lubelski, and Pulawski, but lower for cultivars Marynka and Magnat in cones of infected plants. The content of methylgeranate was lower for infected plants of all cultivars.”
AUTHENTIC GENETICS COMMENTS
The effects of HLVd infection on myrcene production alone suggest that viroids may deserve some special attention from knowledgeable Cannabis growers. Growers may want to look at the potential role of naturally-occurring viroids that are benign or even beneficial in Cannabis as potential ways to enhance specific ‘secondary metabolites’ including Terpenes and Flavonoids for their medicinal effects.
Also, we already know that specific species of beneficial phytobacteria and fungii live in Cannabis flowering tops and that healthy populations of these microorganisms means healthy flowers. Microorganisms not only contribute beneficial compounds to the flowering tops they resist intrusion by pathogenic competitors. Each zone of the Cannabis plant from root to flowering tops has its own distinctive multi-functional microbiome that researchers are just beginning to discover, while as noted above the viroid population of the Cannabis microbiome has still barely been glimpsed.
(from) Cannabis Microbiome and the Role of Endophytes in Modulating the Production of Secondary Metabolites: An Overview
AUTHENTIC GENETICS COMMENTS
Wouldn’t it make sense that viroids would also play a part in Cannabis biology, given the very prominent role they play in Hops, and given the apparently negative impact of HLVd on Cannabis?
Doesn’t the body of this HLVd/Hops/Cannabis research suggest that Viroids are probably already playing a role, both negative and positive, and that maybe we can beneficially learn more about that role?
This seems likely to be especially true when it comes to fine-tuning Cannabis to meet medical needs. Could we learn how to tweak plant viroids to produce medicines for people and animals along with vaccinations for Cannabis plants?
RESEARCH PAPER #2 - SELECTED EXCERPTS
“Evaluation of Disease Severity and Global Transcriptome Response Induced by Citrus bark cracking viroid, Hop latent viroid, and Their Co-Infection in Hop ( Humulus lupulus L.)”
“Viroids are small non-capsidated, single-stranded, covalently-closed circular noncoding RNA replicons of 239-401 nucleotides that exploit host factors for their replication, and some cause disease in several economically important crop plants, while others appear to be benign. The proposed mechanisms of viroid pathogenesis include direct interaction of the genomic viroid RNA with host factors and post-transcriptional or transcriptional gene silencing via viroid-derived small RNAs (vd-sRNAs) generated by the host defensive machinery.
“Humulus lupulus (hop) plants are hosts to several viroids among which Hop latent viroid (HLVd) and Citrus bark cracking viroid (CBCVd) are attractive model systems for the study of viroid-host interactions due to the symptomless infection of the former and severe symptoms induced by the latter in this indicator host.”
Hop (Humulus lupulus L., Cannabaceae) is an economically important crop, mainly cultivated in Europe, western Asia, and North America for specific secondary metabolites, which serve as an essential component in the brewing and pharmaceutical industries.
Among other diseases, viroid diseases pose a severe threat to hop cone production. Currently, hop plants are known to be the host for four viroid species, namely Hop stunt viroid (HSVd), Apple fruit crinkle viroid (AFCVd), Hop latent viroid (HLVd), and Citrus bark cracking viroid (CBCVd).
The infection caused by HLVd has been reported worldwide in hop growing regions. Although HLVd-infected hop plants are symptomless, infection leads to a significant reduction in bitter acids content.
HSVd was first discovered in Japanese hop fields with typical symptoms being reported after 3–7 years of infection, which include stunting, leaf curling, small cone formation, and a substantial reduction of alpha-acid content.
The disease caused by AFCVd is currently restricted to Japanese hop fields, and symptoms caused by this viroid resemble those of HSVd.
Among them, the disease caused by CBCVd is the most aggressive, and symptoms appear after one year of infection. Symptoms include severe bine stunting, leaf down curling, a reduction in cone size, dry root rotting in hops after the first dormancy, and complete plant dieback in 3-5 years.
AUTHENTIC GENETICS COMMENTS
Could this last paragraph signal a potential for the Hop Stunt Viroid in particular to also cross over to Cannabis unless cloning and seed production practices change pretty radically?
RESEARCH PAPER #3 - SELECTED EXCERPTS
“Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus”
“Cannabaceae plants Cannabis sativa L. and Humulus lupulus L. are rich in terpenes - both are typically comprised of terpenes as up to 3-5% of the dry-mass of the female inflorescence.
“The current, comprehensive review presents terpenes found in cannabis and hops. Terpenes' medicinal properties are supported by numerous in vitro, animal and clinical trials and show anti-inflammatory, antioxidant, analgesic, anticonvulsive, antidepressant, anxiolytic, anticancer, antitumor, neuroprotective, anti-mutagenic, anti-allergic, antibiotic and anti-diabetic attributes, among others. Because of the very low toxicity, these terpenes are already widely used as food additives and in cosmetic products. Thus, they have been proven safe and well-tolerated.”
RESEARCH PAPER #4 - SELECTED EXCERPTS
“Elimination of hop latent viroid upon developmental activation of pollen nucleases”
AUTHENTIC GENETICS COMMENTS
This 2008 research says “Hop latent viroid (HLVd) is not transmissible through hop generative tissues and seeds.”
While this is arguable, given later research results, nothing is definitive yet as of 2021 and with the apparent differences in response among Hops cultivars there seems to be a lot yet to be learned.
It may be that, like Hops, some Cannabis cultivars can be infected but asymptomatic, while others may be (or can be bred to be) resistant. It may also be that the viroid load is affected by environmental factors under the grower’s control. And so forth. We’ve included this paper because it’s well done and has a lot of useful information whether or not it is correct about seed transmissibility.
RESEARCH PAPER #5 - SELECTED EXCERPTS
“Complete genome sequence of a hop latent virus infecting hop plants”
“The members of the genus Carlavirus in the family Betaflexiviridae are single-stranded positive-sense RNA viruses. Of them, the hop latent virus (HpLV) is one of three carlaviruses that also includes hop mosaic virus and American hop latent virus.
“They infect the cones of various hop (Humulus lupulus L.) cultivars, which are important bitter flavoring agents used in the production of beer. The HpLV-infected hop plants do not show any visible symptoms, and the hop production damage caused by HpLV has not been determined. In general, HpLV is transmitted in a nonpersistent manner by both aphids and mechanical inoculation.”
RESEARCH PAPER #6 - SELECTED EXCERPTS
“CBCVd and HLVd are transmitted over long distances and introduced into citrus orchards and hop gardens with infected propagative materials. Subsequently they are transmitted mechanically, by grafting and vegetative propagation, and by contaminated tools or machinery (Barbosa et al., 2005).
There are no reports of pollen, seed, or vector transmission of CBCVd in citrus or hops (Duran-Vila and Semancik, 2003; EPPO, 2015). The reports for pollen, seed, and vector transmission of HLVd vary. There is no evidence for insect transmission (Adams et al., 1996; Mahaffee et al., 2009). However, new infections away from neighboring infected hops, led to the hypothesis that a vector may be involved in HLVd spread in hop yards (Adams et al., 1992). HLVd transmission by pollen or seed has been reported as low (Mahaffee et al., 2009; Pethybridge et al., 2008) or none (Matoušek and Patzak, 2000; Matoušek et al., 2008).
RESEARCH PAPER #7 - SELECTED EXCERPTS
“Degradation of hop latent viroid during anaerobic digestion of infected hop harvest residues”
“The fermentation trials showed that HLVd was significantly degraded after 30 days at mesophilic or after 5 days at thermophilic conditions, respectively. However, sequencing revealed that HLVd was not fully degraded even after 90 days. The incubation of hop harvest residues at different temperatures between 20 and 70 °C showed that 70 °C led to a significant HLVd degradation after 1 day. In conclusion, we suggest combining 70 °C pretreatment and thermophilic fermentation for efficient viroid decontamination.”
AUTHENTIC GENETICS COMMENTS
There’s a lot of research that shows that HLVd is sensitive to heat, and while exposing your plants to this kind of heat isn’t a practical way to treat infection, it seems to us that routine composting of all plant waste is just one of many simple things a grower can do to keep their whole environment as free of these viroids and other pathogens as possible.
FURTHER RESEARCH REFERENCES - ANTIVIRAL MILK SOAPS FOR YOUR GROW?
While it may sound strange at first, it looks like Cannabis growers can add a useful layer of anti-viral and anti-pathogen protection to their grow simply by using milk-based soap for handwashing.
Of course there are plenty of other chemical antiviral soaps and washes, but where else can you get a natural soap that has been called “The Grandmother’s Drug’ and has been used effectively for centuries for treating oral HIV infections in Europe and the Middle East?
Check the research below then consider going online and ordering some inexpensive milk soap. You may find you like it even beyond helping keep you grow safe. We prefer Goat milk soaps, but then we feel the same way about Goat yogurt and cheese.
The Remarkable Anti-Viral Properties of Milk
END OF RESEARCH REFERENCES FOR THIS ARTICLE
Thanks for joining us on this brief exploration of a topic that’s concerning a lot of people these days. We hope that by pointing to the remarkable closeness of Cannabis and Hops that we can not only help focus awareness on new possibilities for control and prevention but also on new possibilities for realizing the full potential of Cannabis as a pleasurable medicine for body and soul.
NOW HOW ABOUT A LITTLE MORE SPECULATION?
Viroids and the Origin of Life
We linked to this remarkable paper earlier in the article. This is not settled science but if you missed that link earlier here’s a taste from the intro:
“A huge meteorite (over 100 kg) spread fragments over a large area in South-West Australia in 1969, the Murchison meteorite. Chemical analyses by various research groups indicated the presence of more than 80 amino acids—a surprising number considering the 20 amino acids used by biological entities (cellular organisms and viruses) on Earth. The Murchison meteorite also contained purines and pyrimidines, the building blocks for nucleic acids, sugar-related organic compounds, and there were di-amino acids, aromatic hydrocarbons, and up to 14,000 unique carbon-containing compounds.”
Cause of Cambrian Explosion - Terrestrial or Cosmic?
“Life may have been seeded here on Earth by life-bearing comets as soon as conditions on Earth allowed it to flourish (about or just before 4.1 Billion years ago); and living organisms such as space-resistant and space-hardy bacteria, viruses, more complex eukaryotic cells, fertilized ova and seeds have been continuously delivered ever since to Earth so being one important driver of further terrestrial evolution which has resulted in considerable genetic diversity and which has led to the emergence of mankind.”
Finally some sheer speculation:
DID THE ANCIENT HIMALAYAN BHANG APHID PLAY A ROLE IN THE CANNABIS HLVd EPIDEMIC?
There are good indications, but not yet full proof, that in addition to spreading through Hop clones HLVd can be spread among hop plants by aphids. There are plenty of hop fields in Oregon & Washington, and also a lot of Cannabis grows. This situation has existed since at least the 1960s, when of course the Cannabis grows were clandestine but, we can speculate, may have sometimes been nearby Hop fields. Hops and Cannabis are equally attractive to aphids, and there are species-specific aphids like the Bhang Aphid that may have arrived in North America on early European hemp after riding along from their ancient homelands in the Himalayas millenia ago. Aphids hitchhiked vigorously across continents thousands of years ago and they still do today. A little trip from Hops field to Cannabis grow wouldn’t be a stretch.
So - Could the crossover infection from Hops have originally happened with an Aphid migration to perhaps just a single clandestine Cannabis grow somewhere in Oregon or Washington, maybe 2015 or so? Maybe then those initially infected plants were cloned and sold or shared, or maybe the seeds were sold or shared. Everything considered, couldn’t it be possible that the Wuhan lab of the Cannabis HLVd pandemic was somewhere in an Oregon or Washington Hop field?
A little less dramatic but maybe more likely is that HLVd jumped from Hop plants to Hemp plants centuries ago in Europe, or maybe even millennia ago as Cannabis emerged in the high Himalayas and Hops emerged in the Himalayan lowlands in the same period of time.
Whether or not it turns out that Aphids transmit HLVd, as we all know nobody wants them, so we’re putting together an article on Aphids in general, and the Bhang Aphids in particular, with what science and experience say are the best natural controls and treatments. Please share what you know about these little beasts as a comment on this article on: @ToddPMcCormick or @AGSeedCo