Virus testing on Cattleyas

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southernbelle

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I've completed the testing on my Cattleyas. Still working on the Paphs, Phrags and Phals. So far, all paphs are Virus Free. Here are the stats on the Catts:
50 tested; CymMV + 9; ORSV + 4; CymMV+ & ORSV + 1; Virus Free 36. Total positive 28%
Definitely disappointing the percentage is that high, but thankful I figured this out at this point. I'm also thankful that my most valuable plants are virus free. And, I have a lot of empty bench space for new plants as all the virused plants have been destroyed! I will test each new plant, in the future, immediately upon arrival.
 

abax

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I feel your disappointment, but know that you'll be less stressed in the
future. Catts. seem particularly prone to virus perhaps because they're
so popular and easy to sell to an unsuspecting public. I've rarely encountered
virus problems with Phrags. I do stick with three vendors that I know I
can trust and never do eBay ever.
 

terryros

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Deb and I have collaborated on our virus testing. Out of 60 Cattleyas I had 6 Agdia strip positives (10%). I think I have more species and primary hybrids (the vast majority are crosses and not mericlones or divisions) than Deb and my positivity in those was only 4%.

My Paphs, Phrags, and Miltoniopsis were clean, but every single one of my Phalaenopsis were positive. They were all many years old and I could have obtained them positive as well as spread to them.

Except for a small group of special Paphs, I have a South American orchid collection now. Fortunately, I really like species and primary hybrids and look for new crosses of them rather than divisions or mericlones.
 

southernbelle

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Deb and I have collaborated on our virus testing. Out of 60 Cattleyas I had 6 Agdia strip positives (10%). I think I have more species and primary hybrids (the vast majority are crosses and not mericlones or divisions) than Deb and my positivity in those was only 4%.

My Paphs, Phrags, and Miltoniopsis were clean, but every single one of my Phalaenopsis were positive. They were all many years old and I could have obtained them positive as well as spread to them.

Except for a small group of special Paphs, I have a South American orchid collection now. Fortunately, I really like species and primary hybrids and look for new crosses of them rather than divisions or mericlones.
Terry, I did not mention I had a pretty good thrip infestation last year among catts. From what I understand, they are pretty efficient at spreading viruses. I just wish, before I destroyed my virused plants, I would have noted if they had thrips damage or not. I do know, I have at least 3 healthy plants with scars from thrips from that time.
 

My Green Pets

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Great idea to go ahead and test them all. Sorry so many were infected. I have a couple plants I got last year I haven't tested...but I feel like i should now. Both were seedlings, but I realize that even seedlings can be virus positive. I've read that just by handling cigarettes or tobacco, you get tobacco mosaic virus on your hands and can infect your plants with it. Always something!
 

terryros

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Seedlings from new crosses have an extremely low chance of infection from most any reputable grower. It would probably harm the seedling to remove enough leaf material to do the test, so I think most serious virus hunters don’t test seedlings until they have grown larger. Mericlone seedlings would be in the same situation. I would test any larger plant from a new cross or mericloning and certainly any division from a plant as soon as I got them.

I think Deb and I learned proper disinfectant technique to use when ever we might be contacting plant sap. Having a clean collection of healthy-looking plants lets me be relaxed during routine watering instead of using a hazmat suit and a robot for all contact with my plants. It is not worth taking up growing time and space for a virus infected plants. A few growers have rare heirloom plants that are very valuable and keeping them to use various approaches to eliminate virus are worth a try. These can be kept separated from others. I am not in that situation so virus positive means trash can for the plant and pot.
 

southernbelle

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UPDATE: Testing of all plants completed and these figures hold. NO Paphs or Phrags were positive!! Thank you Hadley and Bill (although I do realize Catts and Phals, being cloned, always show a larger % of virused plants).
 

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Oh that's too bad, was that fusarium or something else? Were there any outward signs on the plants that tested positive, e.g. poor growth, aborted growths, leaf discoloration etc?
 

southernbelle

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Oh that's too bad, was that fusarium or something else? Were there any outward signs on the plants that tested positive, e.g. poor growth, aborted growths, leaf discoloration etc?
Justin, fusarium is not a virus, but a fungus. This was all Oncidium Ring Spot Virus (ORSV) or Cymbidium Mosaic Virus (CymMV). Mostly CymMV, but there were a few OSRV positive and one or two that were positive for both! These are the two viruses that most often attack orchids and the two that tests are readily available for from Agdia and one other company. Viruses are easily spread by the sap (plant fluids) on hands or cutting tools that have not been properly disinfected (which takes some doing). Also when repotting, or from watering run off (according to Keith Davis in NC who usually has tested things through UNC, before he makes those types of proclamations.)
So, since a few of my virused plants were seedlings, it's most likely whatever plants I had that came in virused, I also did some spreading myself. Apparently, unless seed is propagated wet (by cutting into the pod to harvest the seeds) rather than dry harvesting the seed (when the pod bursts), seed propagating of plants should not spread virus. Since cattleyas and phals are cloned, viruses can be transferred that way also, the reason so few paphs and phrags are usually virused and none of mine were.
So now that I've tested everything, and certainly will continue to test any new plants that come in, I should be able to trust my collection will remain virus free. I will still disinfect clippers between each plant because other things (bacterial infections etc.) can be spread by using the same clippers on more than one plant without disinfecting.
I really thought I was being careful by disinfecting clippers with TSP (Tri-Sodium Phosphate) soak (mixed so concentrated it would precipitate out, for 10 min to overnight) as told to by the local orchid vendor between plants, but apparently that is not really effective, as I learned the hard way!
Now, I wear disposable nitrile gloves when I repot each plant and use a separate set of clippers while working on each plant, that then are disinfected by a 3 step process (rinse with soap and water, then Sodium Hydroxide/Virkon S, each 5-10 min) before being used again. I never re-use mix, pots or stakes, etc. This process was recommended by a large grower (with the science to back it up) who I believe is in CA, if I remember correctly. Sounds excessive, I'm sure to most, but I don't ever intend to take this kind of hit again, either financially or from a time standpoint.
Oh, to your question regarding seeing signs. In some cases there was color break on the flowers, an obvious sign of virus. In other, black/purple spotting on the leaves that at first I thought was from too much light, but it was suggested on this forum to be virus and I checked--it was! In some cases the plants had grown and flowered reasonably well several times, but the last flowering was unspectacular both in number and quality of blooms. In a few it was just failure to thrive, but in some cases, no signs had yet shown. So there you have it, hope this has been informative.
 

orchid527

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Justin, fusarium is not a virus, but a fungus. This was all Oncidium Ring Spot Virus (ORSV) or Cymbidium Mosaic Virus (CymMV). Mostly CymMV, but there were a few OSRV positive and one or two that were positive for both! These are the two viruses that most often attack orchids and the two that tests are readily available for from Agdia and one other company. Viruses are easily spread by the sap (plant fluids) on hands or cutting tools that have not been properly disinfected (which takes some doing). Also when repotting, or from watering run off (according to Keith Davis in NC who usually has tested things through UNC, before he makes those types of proclamations.)
So, since a few of my virused plants were seedlings, it's most likely whatever plants I had that came in virused, I also did some spreading myself. Apparently, unless seed is propagated wet (by cutting into the pod to harvest the seeds) rather than dry harvesting the seed (when the pod bursts), seed propagating of plants should not spread virus. Since cattleyas and phals are cloned, viruses can be transferred that way also, the reason so few paphs and phrags are usually virused and none of mine were.
So now that I've tested everything, and certainly will continue to test any new plants that come in, I should be able to trust my collection will remain virus free. I will still disinfect clippers between each plant because other things (bacterial infections etc.) can be spread by using the same clippers on more than one plant without disinfecting.
I really thought I was being careful by disinfecting clippers with TSP (Tri-Sodium Phosphate) soak (mixed so concentrated it would precipitate out, for 10 min to overnight) as told to by the local orchid vendor between plants, but apparently that is not really effective, as I learned the hard way!
Now, I wear disposable nitrile gloves when I repot each plant and use a separate set of clippers while working on each plant, that then are disinfected by a 3 step process (rinse with soap and water, then Sodium Hydroxide/Virkon S, each 5-10 min) before being used again. I never re-use mix, pots or stakes, etc. This process was recommended by a large grower (with the science to back it up) who I believe is in CA, if I remember correctly. Sounds excessive, I'm sure to most, but I don't ever intend to take this kind of hit again, either financially or from a time standpoint.
Oh, to your question regarding seeing signs. In some cases there was color break on the flowers, an obvious sign of virus. In other, black/purple spotting on the leaves that at first I thought was from too much light, but it was suggested on this forum to be virus and I checked--it was! In some cases the plants had grown and flowered reasonably well several times, but the last flowering was unspectacular both in number and quality of blooms. In a few it was just failure to thrive, but in some cases, no signs had yet shown. So there you have it, hope this has been informative.
Just out of curiosity, were the virused seedlings phals or catts. Also, do you have any idea how old they were. The reason I ask is that I test seedlings that I buy, but I really don't know how long it takes to get to detectable levels in seedlings. In other words, I am concerned about false negative results.

Like you, I have not found any virused phrags. I thought I might stop testing them, but since they share trays of water when I go away on vacation, it seems to be too much risk.

Mike
 

southernbelle

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Just out of curiosity, were the virused seedlings phals or catts. Also, do you have any idea how old they were. The reason I ask is that I test seedlings that I buy, but I really don't know how long it takes to get to detectable levels in seedlings. In other words, I am concerned about false negative results.

Like you, I have not found any virused phrags. I thought I might stop testing them, but since they share trays of water when I go away on vacation, it seems to be too much risk.

Mike
Ohhh, I'd do what I needed to do so that they did not share trays of water.

So, it was all catts that were positive except for for one Phal variety (3 plants)! I have (had) 6 phals, 3 of them were the variegated Phal Sogo Vivien marginata. All 3 from the same vendor and all 3 positive!!
I gave away my phals except for these that were special or personal because phals take up a lot of room and when they bloom I move them upstairs to our living area they bloomed for such a long time, I ran out of room for other blooming plants.

Some of my positive catts were older plants (older than 5 years). There is the aspect that in cloned plants the virus might not show up for up to 5 years. Because cloning tissue is taken from new growth, usually the new growth outpaces the virus and can be clean even in a virused plant, but sometimes it takes some time for it it to show up. I have mericlones of older plants that are virused that are clean, so far. One is Rlc. Lawless Walkure 'The Ultimate'. I had one that was virused. Spoke to the vendor because it was a gorgeous flower and asked for an original division. Well the original plants are virused, so no clean ones there, only mericlones are clean (usually). I got one of those. I will test yearly for a couple of years, just to be safe, even though this plant is clearly older than 5 years old and blooming size.
Re seedlings, I don't know how long it would take it to show, but I would think (what do I know) that if it were infected from seed, it would be young. My seedlings were all NBS that were positive. Oh, and when you test, test new growth. At first, I thought I was being smart testing old growth since the cut leaves would not be around as long. Well, I outsmarted myself as the virus is most apparent in the new growth I've read, so I always test one of the newest one or two leaves now.
 

terryros

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Deb, you have really learned your stuff and are presenting it very well. In that most recent round of testing were any more Catts positive?
 

southernbelle

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Terry, thank you!! Coming from you I really appreciate it!! No, all catts had been previously tested. Paphs and phrags and a couple of phals were left which, thankfully, all tested negative.
 

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