Mosaic Virus

Mosaic Virus or should I say Mosaic VIRUSES, is a very common orchids disease caused by a variety of Viruses. The Mosaic Viruses attack numerous orchid genera, especially orchids with long narrow leaves, like the Cymbidiums.

The viruses were firstly noticed over a century ago in Tobacco and fruit and vegetable crops. Symptoms and damage caused differ from plant to plant. For example: In Tobacco it causes distinct circular patters, very similar to patterns caused by Ringspot Virus in Orchids. In other plants it causes the leaves to curl. In other words, Do not believe everything, in this case "One size does not fit all".

In Asia, plants that show "Mutations" (Fasciations) are highly prized. It is a fact that Mosaic Virus has been found in many of these plants and the Virus is considered as the cause of many Mutations.

Some facts: The Mosaic Virus attacks the DNA of the plant. When it comes to orchids, it suppose to cause regular, numerous, almost parallel, broken lines, 1-20mm long. The lines are yellow (Chlorosis). Given time, the yellow varied size strings, will turn black (Necrosis).

Again, the Experts will say: "Throw the plant away and wash your hands afterwards".

PLEASE: If "pests" are spreading Viruses, and Viruses were "killers", how come after millions of years we still have billions of orchids growing wild all over the world?

The fact is, there is no reason to panic. The Mosaic Virus alone, will not kill your plant if the plant is looked after. Two years ago, I purchased 12 perfectly healthy looking, well established,Cympidiums from a highly reputable nursery. A year later all died from a combination of Mosaic Virus and Roots Rot. The Mosaic Virus alone does not kill plants easily. However, if the plant is "neglected", the virus will weaken the plant and the plant will become susceptible to another disease and die.

We know mosquitoes transmit Malaria. Mosquitoes are the carriers of the disease. Malaria survives (is alive) "inside" the carrier (mosquito) with out doing any damage to the mosquito, some sort of "Symbiosis" if you like. That is a proven fact. However, there is NO proof, to suggest that insects that attack orchids, like aphids, scale, mealy bugs, slugs, etc, are carriers. Nobody ever identified any of these pests as "carriers". The most likely transmitter of the viruses is the orchid grower and his cutting tools. That's why, in my opinion, all tools must be sterilized between uses.

Viruses can lay dormant and may surface again in one, two or ten years time. A perfectly healthy looking plant today may display signs of the Mosaic Virus next month. I do not believe that the virus spreads easily. I have Cympidiums with numerous "Pseudobulbs", the leaves of one pseudobulbs showing signs of the Virus, the leaves from the others pseudobulbs, (same plant) show no signs. If I remove the "bad" leaves nobody will know that the plant had a Virus.

Viruses multiply and mutate very fast. If Virus infected leaves bother you, you can remove them.

Destroy the plants if there are signs of a second disease being present like Roots Rot, etc. To stop roots rot spreading.

Remember: The vast majority of orchids do host Viruses.

Dr. George Tsambourakis

24 Mar. 2012


Cymbidium Leave show Mosaic Virus.