Tobacco Mozaic Virus

[Davey]

Is a smoker extremely contagious to orchids? How much does it take to transmit the TMV to an orchid. If someone smashed a cigarette on the their patio, tobacco fell out of the butt, then someone took a blower and cleaned the patio off; would the plants around the blower get the TMV?

[Alice-NJ]

I don't know, but if I'm not mistaken, years back there was a product for killing insects that was called Black Leaf 40 and it was nicotine.

[Vincent]

Tobacco mosaic virus can infect a number of different plants and commercial crops. It is dreaded by agriculturists, including tobacco farmers. They deal with it the same ways orchid growers do -- by taking precautions to prevent infection, inspecting plants, having samples tested, and destroying any infected plants.

For a virus to be passed from cigarette tobacco to an orchid, the tobacco would first have to be infected. The chances of that are not very high. And even if some cigarette tobacco did contain the virus and the virus was still alive, it could only be passed to an orchid by having direct contact with an unhealed wound or damaged root.

In some literature on orchid viruses, I read a warning not to smoke around orchids; that tobacco mosaic virus (if present) could be carried in the smoke and settle on the plants. That might sound like a plausible concern, but it isn't. Any trace of a virus in cigarette smoke would be dead.

That’s because a cigarette burns at extremely high temperatures. Here is a reference that can be found on a number of different web sites:

Temperature without drawing:
Side of the lit portion: 400 deg C (or 752 deg F)
Middle of the lit portion: 580 deg C (or 1112 deg F)

Temperature during drawing:
Middle of the lit portion: 700 deg C (or 1292 deg F)

Aside from that, a plant virus needs a vector of some kind. It doesn't float through the air from host to host, but requires a mechanical means of transmission.

In the scenario you described -- “If someone smashed a cigarette on the their patio, tobacco fell out of the butt, then someone took a blower and cleaned the patio off; would the plants around the blower get the TMV?” -- only if some infected tobacco was blown onto an orchid or into a pot and made direct contact with an open injury on the plant so that the virus could enter into it. I’d say it’s possible, but the odds against it would be very high.

I have researched and thought about these things because I used to be a smoker and regularly smoked while working with my orchids. I never worried in the least about viral transmissions via smoke or believed that virus could be on my fingers just because I had held a cigarette or that virus, even if present, could possibly find a way to jump from cigarettes or fingers into plants. The only precaution would be to keep tobacco from having direct contact with plants, and that’s no problem at all.

The bottom line, in my opinion, is that a smoker is not contagious to orchids.

[caloygwafo]

well how much does it take the transmit TMV to an orchid?maybe the plant disease cause by tobacco mosaic virus is found worldwide..the virus more infect more than 150 types of herbaceous,dicotyledonous plant..an orchid..that's why if anybody want to take the tobacco..tobacco is dying..

[Vincent]

Originally Posted by caloygwafo

well how much does it take the transmit TMV to an orchid?

Do you mean how much does it take in the cultural/environmental sense or do you mean how much of the virus does it take? In either case, here are some examples of how a plant virus can be transmitted:

In nature, a virus can be transmitted very simply from an infected plant to an uninfected one. A leafhopper, for example, pierces a leaf or stem of an infected plant, drinks some sap from it, and then moves to another plant to do the same thing. Even a tiny bit of infected sap residue from the first plant, still on the insect’s beak, can be absorbed into the sap of the second plant when the beak pierces it. Any virus present in the infected sap residue, no matter how little, will quickly begin to replicate within the cells of the new host plant.

Transmission by humans is usually caused with cutting instruments. Pruning or dividing a virused Cattleya maybe, and then using the same tool to prune or divide a healthy one. When a cut is made, infected residue on the blade is introduced into the second plant. This is why pruning tools should always be sterilized after being used, before they are used again on another plant. An orchid grower would surely not take careless chances if he/she has any orchids that are known to be virused, but with good culture, a virused plant might not show symptoms, so appearances can be deceiving.

Transmission can also occur by using the very same water to water more than one orchid. People have done this either by soaking multiple orchid pots in a single, large container, or by catching water as it drains through one pot and then pouring it into another. If an orchid is virused, and if any particle of contaminated matter washes out of its pot and ends up in another one, then the virus may find its way into a new host.

It can also be transmitted from one plant to another if they are situated close enough to each other that their leaves rub together. If the leaves cause abrasions on each other that break through the exterior surfaces, the virused plant can infect the healthy one.

There are various effective defenses against viruses in the natural world. There are also effective defenses in the artificial world. But once a plant has a virus, there is no cure. You certainly wouldn’t want a favorite orchid to become infected.