Virus Report-Many Virused Orchids

[My Green Pets]

Hi Vicki

"Miss Vanda" as you called her also tested positive for CymMV (she's been tested twice).

Have to keep her away from the other plants but she is currently in bloom with 12 or so spikes.

The virus causes some pits and spots on the older leaves when she's stressed but she still grows and blooms well.

It's a tough decision to hold on to infected plants, but if you're giving them away, be sure your friend knows about the virus.

[Tindomul]

I wish you the best of luck, and let's hope the effects of the virus are negligible. And please keep us updated.

[VickiC]

Thank you! Please keep your fingers crossed for me.

Originally Posted by Tindomul

I wish you the best of luck, and let's hope the effects of the virus are negligible. And please keep us updated.

[estación seca]

It is as unrealistic to expect completely virus-free plant collections as it is unrealistic to expect living a long life without catching a cold. Expectations of completely sterile growing spaces are expressions of germ phobia - emotional reactions rather than rational thought.

Virused plants often show no signs of infection, and grow and bloom well. Hobbyists can enjoy them. Of course, vendors should be meticulous about not selling infected plants. But almost no plant keeper has resources to prevent, permanently, entry of sucking insects, and almost nobody has a static collection with no future additions. People complain about expensive plants from commercial growers, but this price reflects expensive practices to prevent selling sick plants. eBay sellers don't take these precautions, so they often sell cheaper.

The various methods suggested above are 100% ineffective at eliminating virus contamination from growing spaces. That could only be done by ethylene gas autoclaving the entire growing space, and gas autoclaves are too small for that. It is possible to reduce pathogen counts with disinfectants, but not eliminate them. Commercial propagators may be willing to spend the VERY LARGE amount of money necessary to ensure virus-free seedlings and mericlones for sale, but hobbyists cannot afford this with their collections.

[VickiC]

Thanks so much for your reply! I appreciate your advice and time.
Vicki

Originally Posted by estación seca

It is as unrealistic to expect completely virus-free plant collections as it is unrealistic to expect living a long life without catching a cold. Expectations of completely sterile growing spaces are expressions of germ phobia - emotional reactions rather than rational thought.

Virused plants often show no signs of infection, and grow and bloom well. Hobbyists can enjoy them. Of course, vendors should be meticulous about not selling infected plants. But almost no plant keeper has resources to prevent, permanently, entry of sucking insects, and almost nobody has a static collection with no future additions. People complain about expensive plants from commercial growers, but this price reflects expensive practices to prevent selling sick plants. eBay sellers don't take these precautions, so they often sell cheaper.

The various methods suggested above are 100% ineffective at eliminating virus contamination from growing spaces. That could only be done by ethylene gas autoclaving the entire growing space, and gas autoclaves are too small for that. It is possible to reduce pathogen counts with disinfectants, but not eliminate them. Commercial propagators may be willing to spend the VERY LARGE amount of money necessary to ensure virus-free seedlings and mericlones for sale, but hobbyists cannot afford this with their collections.

[Tindomul]

Originally Posted by estación seca

It is as unrealistic to expect completely virus-free plant collections as it is unrealistic to expect living a long life without catching a cold. Expectations of completely sterile growing spaces are expressions of germ phobia - emotional reactions rather than rational thought.

Virused plants often show no signs of infection, and grow and bloom well. Hobbyists can enjoy them. Of course, vendors should be meticulous about not selling infected plants. But almost no plant keeper has resources to prevent, permanently, entry of sucking insects, and almost nobody has a static collection with no future additions. People complain about expensive plants from commercial growers, but this price reflects expensive practices to prevent selling sick plants. eBay sellers don't take these precautions, so they often sell cheaper.

The various methods suggested above are 100% ineffective at eliminating virus contamination from growing spaces. That could only be done by ethylene gas autoclaving the entire growing space, and gas autoclaves are too small for that. It is possible to reduce pathogen counts with disinfectants, but not eliminate them. Commercial propagators may be willing to spend the VERY LARGE amount of money necessary to ensure virus-free seedlings and mericlones for sale, but hobbyists cannot afford this with their collections.

Thank you. Also I wanted to ask if you are saying most viruses don't end up killing and deforming the plants that are infected? Eradicating every virus is unrealistic, but are there cases where a collection is infected with a virulent strain that can have the effects I mentioned.
What about the author of this thread, do you think her virused plants are going to be ok in the long run? Just asking because I am learning about this.

[My Green Pets]

Tindomul, In my experience, viruses steal resources from the plants and hijack their cells to reproduce. Some plants can grow normally even when infected, albeit not as robustly as they might when healthy.

Other plants may suffer to a greater degree from a similar infection.

I had an Oncidium with CymMV that grew very slowly, had reduced flower counts, and streaky leaves typical of the infection. I have Vandas with the same infection that, aside from some leaf spots, grow and bloom beautifully.

[VickiC]

Hi Andrew,
I hope you're well and things are good for you these days.

I'll never cease to be impressed with "Miss Vanda"...12 or so spikes! What a lady. I had no idea she had a virus but I did see probably what you are referring to...minor pits and spots/streaks on older leaves. I thought that was very insignificant in comparison to how well she grew and bloomed, though.

No doubt you are still providing her very good care and conditions. She obviously likes Kentucky.

Now, to address me telling or not telling my friend that the orchids I gave her were virused: From the time I decided to have all of my orchids virus tested, I made her aware of that as well as offered her in advance any plants that may test positive. I knew that she had no problem with keeping virused plants away from the ones she already has (which, by the way, may be virused, as well-and she knows that). She thanked me and said that she was glad to get my "positives". As for you...again...I had no idea my/your Vanda was infected. Do you think there's a possibility that she wasn't at the time she lived here ?? That's what I thought. I would never give anyone a virused orchid and not tell them that it is. I know you meant nothing by reminding me not to, so thanks for doing that-although it wasn't necessary.
Take very good care of yourself and your pretty orchids…
Vicki


QUOTE=CambriaWhat;821679]Hi Vicki

"Miss Vanda" as you called her also tested positive for CymMV (she's been tested twice).

Have to keep her away from the other plants but she is currently in bloom with 12 or so spikes.

The virus causes some pits and spots on the older leaves when she's stressed but she still grows and blooms well.

It's a tough decision to hold on to infected plants, but if you're giving them away, be sure your friend knows about the virus.[/QUOTE]

[estación seca]

Originally Posted by Tindomul

Also I wanted to ask if you are saying most viruses don't end up killing and deforming the plants that are infected? Eradicating every virus is unrealistic, but are there cases where a collection is infected with a virulent strain that can have the effects I mentioned.

What about the author of this thread, do you think her virused plants are going to be ok in the long run? Just asking because I am learning about this.

There are many viruses that don't affect the host much, whether the host be a plant or an animal. We great apes, as well as plants, have many different viruses incorporated into our DNA, and we pass a lot of them along to our children. Some are very pathogenic, others somewhat pathogenic and some not very pathogenic. This has been going on for millions of years. It has sometimes had a beneficial effect; geneticists think some plant and mammalian enzyme systems have been improved by insertion of viral DNA.

Different viruses affect different organisms differently. For example, influenza is a gastrointestinal virus for most birds, but influenza is primarily an upper respiratory and lung infection for us. Influenza viruses that look very similar to each other may infect only their preferred species of warm-blooded animal, and not any other.

It is rare for avian influenza to infect humans, but it has occurred. Epidemiologists are always worried an influenza virus that normally doesn't affect humans might acquire the ability to do so. It's beyond the scope of this discussion to explain how that might happen, but it is possible. It might be devastating because humans don't have immunity to these viruses, never having seen them. I wouldn't be surprised to find parallels with plants and plant viruses.

I'm not very well read on plant viruses, but CambriaWhat provided a good example of a plant virus affecting different orchid genera differently.

So... I don't know what is going to happen to VickiC's orchids, but I would not expect all of them to be seriously affected by the virus.

[naoki]

Tindomul, Estacion is right. Different species shows somewhat different responses. Scary part of CymMV and ORSV is that they remains asymptomatic for many species, so it is difficult to notice before they infect other plants. Similar to HIV in this sense. This may be a bit of generalization, but some orchid species may not show symptoms at all if they are infected by CymMV only, but once they get double infection (CymMV + ORSV), they may start to show symptoms.

Studies of plant viruses are not as advanced as animal's, and there are much more viral species than what we know now. But these viruses which are already in our orchids may not be such a problem if they live peacefully. In human, most of us are living with the virus which causes cold sore. But we worry about ORSV and CymMV because they can cause large damage.

Some researchers recently have inserted a coat protein of CymMV into Phalaenopsis, and this made the plant somewhat resistant to CymMV infection (or at least minimized the bad effects of CymMV). It didn't work with ORSV. The exact mechanism is not known yet, but it could have invoked the plant innate defense mechanisms. Plants do have innate defense mechanisms against virus, but those successful viruses are equipped with cheating mechanisms. So if we understand it more, we can find the way toward vaccine.

There are successful rescues of eliminating the virus completely (it was either ORSV or CymMV) via repeated mericloning. But it is too time consuming, and costly.