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Tobacco Mosaic Virus (TMV) in Cannabis Plants: Symptoms and Prevention

There’s no concrete evidence if the mosaic virus can indeed infect cannabis plants, although some growers swear it can. This happens because this virus is hard to come by and not everyone who suffers from it can test it in a lab and when the plants are tested, the results often come out as negative.

Some growers say the symptoms are similar but occur because of different factors that stress your plants and others are certain it’s the virus, despite everything, one thing is certain: you don’t want your cannabis plants to get infected.

1. What is the tobacco mosaic virus?

The tobacco mosaic virus (aka TMV) is a virus widely known for affecting tobacco crops and it’s said it has spread to a lot of different plants, including the cannabis plant.

The TMV is a virus that affects a plant’s development, this virus can live in contaminated tobacco products like cigarettes 1 , contaminated plants, soil or even in bugs that contaminate your plant when they chew on it. This virus can affect a cannabis plant development, affecting yields and the quality of the buds.

2. What does the TMV look like?

It’s impossible to see the virus itself because it’s a microscopic being, but if your plant is affected you will surely see the signs, even though some of the symptoms can be confused for other things, the mosaic pattern your plant will develop is unique and super easy to identify.

If your plants show signs of leaf discoloration make sure your plants indeed are infected with the TMV and are not showing signs of overfeeding or any other plant deficiency that result in yellowing leaves. The tobacco virus cannot be removed and by treating other problems you’ll be actually doing more damage.

3. Where is the TM virus found?

Because it’s a virus, it is inside the plant so you cannot see it, but there are several ways you can expose your plants to it.

Since it’s discovery, researchers have found out that the virus can infect more than 125 species of plants, and not only that, your plants can get infected if you plant them in infected soil or if a bug carrying the virus bites your plant, but the most common way of infection is plant to plant, by direct contact or via your hands after consuming tobacco products.

This means you have to be extremely careful when touching your plants after smoking tobacco because it’s the most common way most cannabis plants get infected.

4. Tobacco mosaic virus symptoms

The symptoms your plant shows after getting the TM virus will depend, the most common symptom 2 is a mosaic-like pattern on some part of the leaves, this alone won’t damage your plants but because there’s no way to remove it from a plant, this specific plant won’t be suited for breeding.

In more serious cases, you will see a mosaic pattern and some strange plant growth, this virus can cause the leaves to grow deformed, twisted and with a slower development, despite not damaging your plant, the unusual growth will affect the yields and depending on how your plant develops, it can also affect the quality of your harvest.

Mild Symptoms Severe Symptoms
Distinct yellowing of the leaves veins Plant deformation
Yellow spotting Stunted growth
Mosaic pattern on the leaves Twisted leaves

Have in mind that you plant can show both mild and severe symptoms at the same time, the signs your plant gives will depend on the strain and can vary from case to case, even though some symptoms like twisted leaves and deformation can be caused by other things, the unique mosaic pattern will help you identify if your plant has the tobacco mosaic virus more easily.

5. How to prevent it?

There’s no way to prevent the tobacco virus other than always:

  • Sanitizing your tools;
  • Buying soil or clones from a reputable vendor;
  • Washing your hands after smoking tobacco or dealing with infected plants.

This virus can infect your plants by simply touching them so the best way to prevent it is always washing your hands before working on your garden and always make sure everything you bring in your garden is safe.

6. How to deal with it?

Unfortunately, there’s no way to remove the virus, once your plant or soil is infected because viruses cannot be controlled once they have been transmitted, this is why your best option is to prevent getting it.

If your plants get infected you should remove them from your garden, this not only applies to cannabis plants because the TM virus can infect all other plants in your garden and once it has spread throughout your garden, you’ll have to get rid of all the plants so as soon as you spot it, it’s better to remove it, remember the virus can even be transmitted by hand so it’s not worth it to risk it.

7. In conclusion

Even though the tobacco mosaic virus won’t damage your plants like bugs do, it can become a vicious cycle, infecting all your plants around. It’s crucial you take care of infected plants as soon as you spot them and if you don’t want to remove them, maybe isolate them and always wash your hands and every piece of equipment you use before touching other plants.

If you have seen it on your crops or have important information to share with fellow growers, please leave a comment in the comment section below!

External References:

2. Tobacco mosaic virus – Rifkind, David & Freeman, Geraldine. (2005).

The TMV is hard to come by in cannabis but it can affect the development of the leaves with deformed growth and odd coloring, ultimately affecting yields.

Tobacco Mosaic Virus In Cannabis

Tobacco Mosaic Virus was the first virus ever described. It’s study led to the development of contemporary molecular biology. It may have an interesting history but TMV can really devastate a cannabis crop if left to run riot. So what’s the deal with marijuana and TMV?

TOBACCO MOSAIC VIRUS

Tobacco Mosaic Virus is a pathogen found in tobacco. It causes patchy and mottled leaves, slow growth, distorted new growth and leaf tips and decreased yields. It is uncertain whether TMV actually infects cannabis, but the symptoms coincide with the indicators reported in other plants. It is still being debated.

The symptoms are often first diagnosed as over-feeding or as other plant pathogens such as Fusarium Solani or Rose Black-spot. An infestation of Broad or Russet mites also present similar symptoms.

Tobacco Mosaic Virus is a “contagium vivum fluidum” or an infectious soluble agent that can migrate from plant to plant. It has jumped from tobacco to over 125 other species of plant. These include squashes, marigolds, spinach, peppers and tomatoes.

SYMPTOMS

Just like with other plants symptoms can vary from an absolute plant wide infestation to only a few leaves. Depending on genetics some plants can be carriers and show no symptoms at all.

* Curved leaves with yellow stripes or mottling in a mosaic pattern are the main symptoms of this disease.
* Yellowing is worse on the parts that are deformed.
* Older leaves that display yellowing symptoms will be thin and crepe like. Where still green the leaf will remain relatively unchanged.
* The effects can be better seen when the affected leaves are in shade.
* Young plants will become stunted with new growth being heavily mutated, fern-like or twisted.

PREVENTION IS BETTER THAN CURE

Commercial nursery practices are advised always. They can help prevent not only TMV but many other pathogens from infecting your plants.

Strict sterile practices are a must:
* Wash your hands thoroughly with soap and water before touching your plants or wear gloves.
* Change gloves or wash your hands again between handling each plant.
* Wash down your growspace and equipment with an agricultural sanitant before each new crop.

Plants with good genetics are less susceptible to many diseases and fungi that can affect cannabis. Choose strains with reputable strength.

WHAT IS THE CURE?

Unfortunately there is no cure for TMV. If there is a severe infestation all plants and soil must be destroyed. TMV won’t necessarily kill your plants, but overall growth rates and end yields will be severely compromised. Hydroponic systems have less chance of catching the virus as it is soil borne.

Although not a cure for this blight, adding aspirin to your watering routine can improve the plants health. End yields will still be compromised, but they will be much better than plants that have been untreated. The master gardener at the Univesity of Rhode Island suggests 1 uncoated aspirin to 4 litres of water and water in regularly.

VIRAL HISTORY

Tobacco Mosaic Virus was the first virus ever discovered and stands out as a milestone in virology history. Originally it was described by Ivanoski in 1892 then confirmed as a virus by Beijerinck in 1898. At the time tools and concepts to handle this new type of agent were non existent. It wasn’t until 1935 that the TMV was isolated as an enzyme-like protein. Then later in 1937 it was better characterized as a nucleoprotein. These discoveries were key in developing the field of molecular biology as we know it today.

It might have an interesing history but Tobacco Mosaic Virus can be a blight for marijuana and heartbreak for cannabis growers.