Prevention is the only solution
Science knows much more about viruses that attack human beings than those that attack plants. Obviously we know some viruses that are really pernicious for our cannabis plants. Probably the best known is the Tobacco Mosaic Virus (TMV).
Plant viruses need certain kinds of host cells thrive. These host cells are not present in all types of plants. Therefore, there are viruses that affect cannabis but cannot affect other types of plants with different cells. But, unfortunately, there are some viruses with a great range of species to attack. These ones are the most devastating.
Plant viruses are a protein capsid that contains genetic material. They can move from one plant to another without a vector. However, we have seen very often how a whole crop has been ruins through a virus. How can it be possible if the viruses cannot move? It happens because they use a vector. And many times, the vector is the owner of the plants. Sometimes, the vectors are pests, such as trips, white flies, aphids, and so on.
As soon as the viruses reach the host cells they shed from their protein capsid and begin to thrive. From that moment on, new capsids and proteins get formed to carry the virus from cell to cell in the plant. Tobacco Mosaic Virus especially attacks tobacco plants; but it affects quite a few more plants, such as cannabis.
The capsid of TMV has more than 2000 molecules of coat protein and one molecule of coat protein and one molecule of genomic single-strand RNA. When the virus reaches the host cell, it releases itself from its protein capsid to liberate its viral RNA strand and begins to replicate its own genome.
The virus produces discoloration between the veins of the leaves. If you are not expert grower it is possible and easy to think the cause is nutrient deficiency. This first symptom is followed by the appearance of mottling that remind of a mosaic which has light and dark patter. Some leaves can develop wrinkles and become contorted. Again this can be confused with nutrient problems. Many leaves will die and the plant quits growing.
Among the different viruses that can attack our cannabis plants, TMV is probably the most stable one. If the temperature does not drop below 40 degrees (Celsius), the virus will remain stable. Due to this factor, indoors cultures and greenhouses are the best place for them to thrive among many plants. In fact this virus can easily kill the whole culture.
Cannabis can be affected by other viruses too. TMV is not our only enemy. Moreover, we can find a cannabis plant infected by different types of viruses. This situation is terrible and if it happens, it will be difficult to cure the plants. First of all because we will tend to think it is a question of nutrient problems.
Although there are many viruses that attack the plants, when it comes to cannabis only two have been deeply studied: Hemp Mosaic Virus (HMV) and Hemp Streak Virus (HSV). In both cases, aphids are the main vector to infest other plants. If you have read our article “Insects to fight pests in cannabis plants”, you know how to fight and, above all, how to prevent these viruses. And if you have read our article “Biological fight against cannabis pests” you must know that the best way to prevent all type of viruses is growing very healthy plants, which is a task that begins from the very beginning in a culture. You must choose the best seeds and grow them as it has to be perfectly done. It is worth it!
Viruses are a nightmare for plants, animals and human beings. When it comes to cannabis plants, besides the ones we have mentioned before, we cannot forget others, such as Tobacco Streak Ringspot Virus (TRSV), Tobacco Streak Virus (TSV), Alfalfa Mosaic Virus (AMV). These viruses also use aphids and seeds as vectors and the leaves of the plant show mottling and poor growth too.
Arabic Mosaic Virus (ArMV) infects cannabis plants through seeds and nematodes. Once again we recommend you the read the articles we have mentioned few lines before. On top of it, the ArMV tends to hide symptoms until it is too late.
Even though they are not as common as the previous ones, we cannot forget Cucumber Mosaic Virus (CMV) and Tomato Ringspot Virus (TomRSV). Again both aphids and seeds are believed to be the main vectors to expand these two disgusting viruses.
There is no way to cure plants infected by viruses
Since viral diseases have not treatment, prevention is the only way we have to fight this problem. As soon as you detect an infected plant, remove it at once and take it away from the rest. Burn it and use globes and especial clothes because remember human beings are good vectors for viruses.
Your indoor room must be perfectly clean before germinating a single seed. Use bleach or whatever efficient enough to kill all viruses. Keep the whole environment clean (this includes you).
Some strains are more resistant than others. Certain varieties are prone to get infected. As a rule you must choose seeds from good and serious banks.
A plant without pests or parasites is less sensitive to viruses. Once again we must go back to the articles we mentioned before. Using the biological techniques we wrote about in cannabisground.com you should be able to grow strong and healthy plants. Do you remember what we said about predators and prey? If you do, then you know the viruses are the predators and weak or infested plants are their favorite prey; the one they will choose to attack.
And above all you must remember that prevention is the key to any problem. It is always better to prevent than to cure. If a human being gets infected by a virus, he can use antibiotics. A plant cannot.