Cannabis Virus/Disease Eradication Toledo, OH

Grower, Education, Michigan. Horticulturist, Oakland

Cannabis disease symptoms are appearing in crops around the world, but the cause is still a mystery. Here’s what we know about possible causes, detection, and what you can do to stop viral spread.. People around the world are grappling with the health and economic consequences of COVID-19. Viral contagions are gaining public attention at a record pace, making this an ideal time to address disease issues in the cannabis industry. When dangerous viruses emerge and adapt, it isn’t just humans who are at risk, as the novel coronavirus pandemic is demonstrating. Lower vigor, lower flower yields, and reduced cannabinoid and terpene production are becoming more common economic consequences for cannabis growers. The symptoms of “Cannabis disease syndrome” (CDS) are consistent, but there is no single cause for them. “Dudding” and “dudders” are common terms for these symptoms, which don’t appear to be caused by nutrient deficiencies or other pathogens. (The term “just a dud” was coined by growers to describe plants with reduced vigor or stunted growth.)

Commercial Cannabis clones have been showing signs of dwindling vigor for some time now. It was not uncommon for growers to see a clone weaken and become less productive after each flowering of cuttings during the 1980s, when vegetative reproduction by rooting cuttings became popular. Few other signs of infection could be found, aside from a decreased yield. Because of this, we’ve dubbed it the “photocopy effect” because it’s similar to the effect that occurs when you copy something that has already been copied. A shift in gene frequency within a small sexually reproducing population, known as “genetic drift,” could not account for the observed loss of vigor in serial asexually multiplied cuttings. The reasons for the decline in vigor have baffled the growers, who have even considered the possibility that taking serial cuttings is to blame. In no time at all, we discovered that our symptoms were due to an infectious disease spreading from person to person and that the disease was spreading rapidly. More on this in a moment.) To prevent the spread of the disease, we wiped out clones showing symptoms, sterilized benches, pots, and tools, and began taking cuttings from each mother plant with new blades. There were no known causes, but the effects were obvious. However, we were able to come up with workable solutions, and the problem was all but solved.

The current CDS and COVID-19 share some characteristics. CDS, like the human coronavirus, has a wide range of symptoms, making it difficult to diagnose at first. We and other growers have learned that CDS can be transmitted by vegetative plants, but flowering plants are more likely to suffer the consequences of the infection. It is difficult to detect the symptoms of these diseases because they can be mistaken for those of other illnesses, which makes them difficult to detect in large populations. As with CDS and COVID-19, asymptomatic plants can infect the otherwise healthy, with more serious consequences for some than others. Only a few laboratories are capable of identifying the pathogens that cause infections, and these laboratories are few and far between. There are currently no solutions to stop the spread of these diseases other than social isolation and the establishment of quarantines.

Although a primary pathogen has been identified as the primary cause of cannabis disease syndrome, it cannot be attributed to a single cause (more on this later). Symptomatic plants may be infected by multiple pathogens, making it even more difficult to identify and control the problem. There is no doubt that the spread of CDS would have been much slower having CDS killed more of its hosts rather than making them ill. Taking cuttings from diseased plants and propagating them as mother plants is the fastest way for the cannabis disease syndrome to spread, as we’ve seen in our research on affected plants.

How can we know if our plants have CDS?

They differ from their healthy counterparts. Clones that the grower has a personal connection to are more likely to show signs of CDS, which are difficult to detect. First and foremost, a CDS infection results in a decrease in productivity because of a decrease in vigor. Flowers are smaller and resin gland development slows down as a result of slower growth. It appears that the lower branches are growing away from the central stalk and sag, while the main stem remains upright. Brittle stems that easily break when bent; distorted leaf growth; variegated and chlorotic leaves; overall stunted growth, resulting in drastically reduced terpene and cannabinoid expression are other common symptoms. HpLVd may initially be asymptomatic, but as the disease progresses additional symptoms such as stunted growth, general yellowing of the foliage, discolored mosaic blotches or streaks, interveinal yellowing, deformed leaf margins of younger leaves, and discoloration within the stems appear, all characteristic symptoms of possible opportunistic coinfection by fungal or bacterial pathogens.

Confusion is exacerbated by the fact that plants infected with HpLVd may show symptoms that are actually favorable, such as darker green foliage and increased branching, which makes detection and controls more difficult while also increasing the disease’s spread through the propagation of seemingly healthy cuttings. The only way to confirm the presence of HpLVd is through a specialized laboratory’s molecular testing. Sample collection is complicated by viral infections, which can spread from infected to uninfected areas of the same plant. Only a few limbs or leaves of a plant may be infected. The only way to be sure that a plant is healthy before destroying it is to conduct multiple tissue tests from various parts of the plant. Each clone must be tested for pathogens and the cutting must be checked to make sure it is free of contamination.

How can we control CDS?

Preventative measures like using condoms, avoiding reusing needles, and sterilizing razors were already being advised by health care organizations long before the discovery of the human immunodeficiency virus (HIV). They knew how serious AIDS was and what they could do to stop it from spreading long before they discovered what was causing it. Control of plant pathogens relies heavily on education, prevention, and suppression, just as it does in the fight against human viruses. Testing must begin as soon as awareness is raised in our community in order to discover the disease’s causes and the extent to which it has spread. All infected plants must be either quarantined or destroyed if they are discovered. There is a chance it will go away or at least reach levels where widespread economic damage is not incurred if the CDS spread is halted. In order to keep pathogenic diseases like CDS from spreading, growers can take a number of precautions.


Control pests.

Vectors of viral transmission include common Cannabis pests like aphids, whiteflies, thrips, and mites, which feed on infected plants and then feed on uninfected plants to transmit and widely spread viruses and other pathogens. Every grower should have an effective pest control plan in place.

Keep it clean.

The plant’s vascular system is vulnerable to infection every time a cutting is taken. In order to prevent the spread of disease when starting new mother plants, use fresh, sterile blades straight from the package or sterilized scissors for every cut. Containers, benches, and growing media can also spread bacterial and fungal infections. A cheap and effective disinfectant is household bleach diluted with five parts water. Spray down equipment, soak scissors, saturate containers, and wipe down workbenches with rags and a spray bottle. Root cuttings and grow flowers in sterile media. Before moving on to the next mother plant, wash and sterilize your hands or change gloves. Purchasing stock from a reputable nursery is always preferable when it comes to ensuring that it is clean.


Your facility should have an isolated quarantine area for any incoming newcomers until you can be certain that the newcomers will be free of disease. (Again, testing is the only way to be certain that a plant is healthy.) Before propagating your mother plants, flower a few cuttings in isolation and keep an eye out for disease symptoms. Don’t bring in any foreign plants at all. As we’ve seen time and time again, cuttings from other plants can infect a plant.

Limit visits

People who come into contact with plants that have been infected can contract diseases, as can people who come into contact with infected plants. People who have come into contact with potentially infected plants, such as other growers, should be kept out of your quarantine and propagation areas to prevent the spread of CDS. New arrivals to your facility should be isolated in a sterile quarantine area until you are sure they are not infected. Only by testing can you be certain that a plant is healthy.) Before propagating your mother plants, test a few isolated cuttings for disease symptoms. Even better, refuse to accept any plants from other countries. As we’ve seen time and time again, cuttings from other plants can infect a plant.

Destroy affected plants

Any mother plants you suspect are infected can be easily, cheaply, and effectively eradicated by simply destroying them. The cuttings should be labeled and numbered so that you can later trace each cutting back to its mother. This entire clone—the mother plants and all of their offspring—should be destroyed if any cuttings are found to be infected.

Shoot N Roots; Cannabis Virus/Disease Eradication Toledo, OH

When it comes to learning about cannabis tissue culture in Michigan, Shoots n’ Roots is the state’s gold standard. Those who enroll in our course or purchase our Facility Consultation package will gain knowledge about operating a cannabis tissue culture operation, including the proper protocol, technique, equipment, and troubleshooting.