quiltergal
Orchid Slave
This is probably a dumb question but are Paphs and Phrags susceptible to common orchid viruses such as ORSV & CymSV? I can't remember ever reading that someone suspected their Paph/Phrag had a virus. 
Virus in Paphs & Phrags
- Thread starter quiltergal
- Start date
Help Support Slippertalk Orchid Forum:
emydura
Well-Known Member
I remember reading this on a website which has now be closed down -
Paphs initially appear to be free from parasites and deseases that usually afflict other genera of orchids, however, looks can be decieving. It is now known that at least 6% of all Paphiopedilums in cultivation are infected with CMV or OFV, with a likelihood of a much higher infection rate with unknown viruses. Studies completed by Xavier de Loubresse suggest epidemic infestation with unknown viruses and diseases living in vascular tissues, likely accounting for the regarded slow growth.
Viruses
Viruses are a horror for Paph growers, worst of all because they typically show no symptoms. It used to be said that Paphiopedilums did not get viruses, but a recent test of a paph collection came up with a 4% infection rate. Plants long in cultivation and used for the cut flower trade are most likely to be infected. For instance Paph. King Arthur from the tested collection was infected.
Known Paph Infectous Virii: Cymbidium Mosaic Virus, Tobacco Mosaic Virus.
Symptoms: Often there are no visual symptoms. Growth rate is often your best indicator.
Diagnosis: The best method for diagnosis is to examine a tissue sample under an electron microscope. However, electron microscopes are typically only available at Universities and research laboratories. Your local micropropagation lab should be able to tell you if your plant material is virus-infected. This typically requires a simple ELISA, SIN, or ENTA test.
Transmission: Frequently transmitted from plant to plant by insects. Human transmission by the use of unsterilized tools, pots, table tops, benches, hands, reused water for watering several plants, is the most frequent cause. See horticultural hygiene. Propagules are also found on seeds harvested by green pod culture
Treatment: There is no cure for virii. Plants must be burned entirely. If you have access to a premium service lab, it may be possible to clone virus-free Paphiopedilum tissues from meristem to recover costly breeding plants, however such services would be very costly.
Paphs initially appear to be free from parasites and deseases that usually afflict other genera of orchids, however, looks can be decieving. It is now known that at least 6% of all Paphiopedilums in cultivation are infected with CMV or OFV, with a likelihood of a much higher infection rate with unknown viruses. Studies completed by Xavier de Loubresse suggest epidemic infestation with unknown viruses and diseases living in vascular tissues, likely accounting for the regarded slow growth.
Viruses
Viruses are a horror for Paph growers, worst of all because they typically show no symptoms. It used to be said that Paphiopedilums did not get viruses, but a recent test of a paph collection came up with a 4% infection rate. Plants long in cultivation and used for the cut flower trade are most likely to be infected. For instance Paph. King Arthur from the tested collection was infected.
Known Paph Infectous Virii: Cymbidium Mosaic Virus, Tobacco Mosaic Virus.
Symptoms: Often there are no visual symptoms. Growth rate is often your best indicator.
Diagnosis: The best method for diagnosis is to examine a tissue sample under an electron microscope. However, electron microscopes are typically only available at Universities and research laboratories. Your local micropropagation lab should be able to tell you if your plant material is virus-infected. This typically requires a simple ELISA, SIN, or ENTA test.
Transmission: Frequently transmitted from plant to plant by insects. Human transmission by the use of unsterilized tools, pots, table tops, benches, hands, reused water for watering several plants, is the most frequent cause. See horticultural hygiene. Propagules are also found on seeds harvested by green pod culture
Treatment: There is no cure for virii. Plants must be burned entirely. If you have access to a premium service lab, it may be possible to clone virus-free Paphiopedilum tissues from meristem to recover costly breeding plants, however such services would be very costly.
D
DavidCampen
Guest
I test my plants for ORSV and CymMV using the Agdia Immunostrip:
https://orders.agdia.com/InventoryD.asp?loc=IN&collection=ISK 13301&attribute_Size=25
https://orders.agdia.com/InventoryD.asp?loc=IN&collection=ISK 13301&attribute_Size=25
I had virus on a Phrag Grande 'Maybrook'.
CymMV I tested it with Agdia Immunostrip
If you want to see a few pictures:
http://www.slippertalk.com/forum/showthread.php?t=18983&highlight=grande+maybrook+virus
CymMV I tested it with Agdia Immunostrip
If you want to see a few pictures:
http://www.slippertalk.com/forum/showthread.php?t=18983&highlight=grande+maybrook+virus
L
lepetitmartien
Guest
For now, the only way to get rid of a virus is thru micropropagation, either by the selection of the seeds (viruses are mostly in the cotton fibers of the capsule and at the surface of the seeds) or with virucid in vitro treatments for CyMV (note: heavy and complicated procedure).
Unfortunately it does not work for ORSV, and it won't save the mother plant.
(sources available on STAUG website, like the pdf of Dr. Ching-An Chang)
Unfortunately it does not work for ORSV, and it won't save the mother plant.
(sources available on STAUG website, like the pdf of Dr. Ching-An Chang)
Terri
I test all of my orchid purchases using the Agdia test strips. This includes more than 200 paphs and only one tested positive for CymMV. This was a mature, multigrowth plant from a grower who also sells phals. My guess is that it was infected during repotting or by an insect vector. It did not show any symptoms.
I'm not sure I would test for virus if I only grew paphs and purchased only flasks or small seedlings.
Mike
I test all of my orchid purchases using the Agdia test strips. This includes more than 200 paphs and only one tested positive for CymMV. This was a mature, multigrowth plant from a grower who also sells phals. My guess is that it was infected during repotting or by an insect vector. It did not show any symptoms.
I'm not sure I would test for virus if I only grew paphs and purchased only flasks or small seedlings.
Mike
E
Eric Muehlbauer
Guest
From what I have read, paphs tend to be more resistant to viruses than other orchids, and, even when infected, are symptom free. As pointed out, virus seems to be associated with older clones used in the cut flower trade. Since paphs can be propagated by breaking off growths, rather than cutting them, and are not propagated through tissue culture, the main sources of viral infection are removed.
Good photos. That does look like a subtle version of infected Cymbidium leaves.
quiltergal
Orchid Slave
Thanks very much everyone for your feedback.
newbud
Orchid Maniac
I too want to thank you. I had no idea what a virused plant looks like. Fortunately or unfortunately I found a plant with very similar markings on the leaves and the plant over all just doesn't look well. No new growths. It came in bloom (Phal. equelacea) and was a beautiful flower but I have no doubt it has something. I'm extremely worried though as I had it in contact with several other plants and am afraid it will spread. I wish I could afford the ELISA strips but they are so cost prohibitive unless several of us went in and bought a pack of them. Does anyone have two or three they could sell?
newbud do you have a picture of your Phalaenopsis?
Justin
Well-Known Member
email critter creek laboratory - you can send them a sample to test for a few dollars.
L
lepetitmartien
Guest
Can you show us a pic or two?
I strongly recommend you to read the literature available at STAUG :
Sue Bottom's
http://www.staugorchidsociety.org/PDF/OrchidPestsandDiseasesbySueBottom.pdf
Articles, pdf and pics:
http://www.staugorchidsociety.org/culturepests-viruses.htm
It's no fun, but you'll have the best input you can get right now (save from a veg virologist).
The only exhibitions of virus activity than can be reasonably linked to viruses are :
- color breaks (especially if repeated)
- odd regular spots on leaves, but these are to take with caution.
The other eventual symptoms can be easily mistaken with something else (chlorosis, yellow zones, necrosis…), or a slower than normal growth is sometimes too vague save when going thru all things after diagnosis.
Only a test can give a better input. if only they were cheaper.:sob:
Remember slow fungi or bacterias can be really awful looking, setting a plant on the road to death and have nothing to do with a virus. If you can spare it, send a sample to a lab.
Immunostrips here are about 8-9€/piece in Europe, the most difficult being to be able to buy some… (fortunately I have a source where I can fetch them be they needed…)oke:
I strongly recommend you to read the literature available at STAUG :
Sue Bottom's
http://www.staugorchidsociety.org/PDF/OrchidPestsandDiseasesbySueBottom.pdf
Articles, pdf and pics:
http://www.staugorchidsociety.org/culturepests-viruses.htm
It's no fun, but you'll have the best input you can get right now (save from a veg virologist).
The only exhibitions of virus activity than can be reasonably linked to viruses are :
- color breaks (especially if repeated)
- odd regular spots on leaves, but these are to take with caution.
The other eventual symptoms can be easily mistaken with something else (chlorosis, yellow zones, necrosis…), or a slower than normal growth is sometimes too vague save when going thru all things after diagnosis.
Only a test can give a better input. if only they were cheaper.:sob:
Remember slow fungi or bacterias can be really awful looking, setting a plant on the road to death and have nothing to do with a virus. If you can spare it, send a sample to a lab.
Immunostrips here are about 8-9€/piece in Europe, the most difficult being to be able to buy some… (fortunately I have a source where I can fetch them be they needed…)
oke:
I don't think mystery invisible viruses are something to be concerned about. All species play host to viruses which are non-pathogenic (i.e. don't cause any kind of sickness). That 4-6% of Paphs in one collection had an infection but showed now sign of illness should say it all: this isn't something to worry about. My ancient Paph King Arthur (which originates from an old orchid nursery with a high turn-over of plants) is one of my more vigorous growing plants. Maybe it is infection free, maybe it isn't? I think for us the only issue is whether the plant is sick not what virus or fungi it is hiding.
I totally agree with you Tyrone! The most important thing for me is the vigor of the plant,virused or not. Just take reasonnable precautions like sterilising tools before every use and let nature be nature. It has done very well without us for a very long time.
Justin
Well-Known Member
it depends what your goals in growing are. if you have valuable awarded divisions or are interested in breedng then the threat of virus is a nightmare and any virused plants should be discarded. even if that isn't your thing, you wouldn't want infected plants passed around at the orchid society etc.
the only way to be sure is testing. i mentioned critter creek labs above as an inexpensive option.
the only way to be sure is testing. i mentioned critter creek labs above as an inexpensive option.
I have a friend who researchers potato viruses. His funders (the local potato industry) were horrified to learn that not only are all our potatos full of viruses but the viruses were imported decades ago without anyone knowing . Not only can he show by DNA sequences that all these viruses exist but that they have evolved locally as the potatos have been distributed and that even new "clean" strains also carry viruses. All the while the local farmers are producing tons of potatos, in fact, here in South Africa potatoes are a guaranteed cash crop. If you are going to start worrying about viruses then you may as well stop breeding, sharing plants and holding shows where the viruses can swap out because we simply can't stop their spread. If we had billions of USD to waste testing each plant for virus we would probably end up discarding 99% of our plants. That just nature. The only thing we need to be paranoid about is plants which are sick and have evidence of viral infection (rust-like marks, deformed leaves etc...). There is no need to go Michael Bloomberg over plant viruses. There are more serious windmills to tilt at, such as bacterial infections.
Plants have been around for hundreds of millions of years. Orchids were there when dinosaurs were. Viruses and every other diseases have preyed on plants and animals since the beginning of life.
Plants, like animals, have developped resistance to viruses and those that haven't die. We have to live with those pathogens and make the best of things. In my growing room, I worry far more about bacterias and fungus, not to mention the lack of this or that nutrient. If a plant doesn't perform, while most others do fine, it eventually goes on the trash pile, virus or no virus.
Plants, like animals, have developped resistance to viruses and those that haven't die. We have to live with those pathogens and make the best of things. In my growing room, I worry far more about bacterias and fungus, not to mention the lack of this or that nutrient. If a plant doesn't perform, while most others do fine, it eventually goes on the trash pile, virus or no virus.
I agree with Justin. Test your plants.
The last thing I want in my greenhouse is a plant with CymMV or ORSV that shows no symptoms, yet is available as a source of infection for other plants. Sooner or later most of us will slip up and cross contaminate plants while repotting or we will have an infestation of thrips or other virus vectors.
Seems like there are only two prudent strategies to follow:
1) Test every incoming plant as part of a barrier strategy and retest any suspicious plants. Retest plants that become part of your core collection. This way you catch previous false negatives and you can be confident that the plants with the longest residence are clean. Of course, this is tedious and impossibly expensive if you have a lot of plants.
2) Don't bother to test, but buy only flasks or small seedlings. Never buy untested meristemmed plants and never buy from sources that have a lot of untested meristemmed plants mixed in with their seedlings. If you you don't have the time for the plants to grow to flowering size or if you are the poster child for instant gratification, this strategy will not work for you.
In either case, you need to throw out all sickly plants and use the appropriate preventative measures, such as clean cutting tools, medium and pots.
If you don't use either of these 2 strategies and you have more than a few plants, then you already have virus in your collection, especially if they spend time outside in the summer, and especially if you have any phals. Also, if you can't test all of your plants, it is a waste of time and money to test just a few. If they look bad, throw them out. Don't feel bad about having virus in your collection. I would guess that more than 95% of the growers do. I just don't want it in mine.
Mike
The last thing I want in my greenhouse is a plant with CymMV or ORSV that shows no symptoms, yet is available as a source of infection for other plants. Sooner or later most of us will slip up and cross contaminate plants while repotting or we will have an infestation of thrips or other virus vectors.
Seems like there are only two prudent strategies to follow:
1) Test every incoming plant as part of a barrier strategy and retest any suspicious plants. Retest plants that become part of your core collection. This way you catch previous false negatives and you can be confident that the plants with the longest residence are clean. Of course, this is tedious and impossibly expensive if you have a lot of plants.
2) Don't bother to test, but buy only flasks or small seedlings. Never buy untested meristemmed plants and never buy from sources that have a lot of untested meristemmed plants mixed in with their seedlings. If you you don't have the time for the plants to grow to flowering size or if you are the poster child for instant gratification, this strategy will not work for you.
In either case, you need to throw out all sickly plants and use the appropriate preventative measures, such as clean cutting tools, medium and pots.
If you don't use either of these 2 strategies and you have more than a few plants, then you already have virus in your collection, especially if they spend time outside in the summer, and especially if you have any phals. Also, if you can't test all of your plants, it is a waste of time and money to test just a few. If they look bad, throw them out. Don't feel bad about having virus in your collection. I would guess that more than 95% of the growers do. I just don't want it in mine.
Mike
Tell you what Mike! If you got a strong, flowering size phrag or multifloral paphs that grows well, flowers well and is virused, send it to me. I'll even pay for postage.
oke:Michel
