Viruses and orchid collections

[NYCorchidman]

Originally Posted by brooke

Critter Creek can test for more viruses than the normal ones if requested and of course for more money.

Brooke

Oh, thank you! good to know! I will have to send sample of some of my dendrobiums that display strange stuff on their leaves, which look nothing like CymMV or ORSV.
just out of curiousity, I should give it a try and see what comes up.

[Leafmite]

I am not going to ever test. If there are suspicious leaf markings or color break and unexplained loss of vigor...goodbye little plant. I keep the new plants away from the older ones. I don't grow my orchids in perfect conditions. I don't fertilize during the winter (which can mask symptoms). We have had drought and a heatwave last summer and near the window, the temps have been really cold. Humidity varies daily depending on how much the furnace runs. If an orchid is thriving even so, I am going to trust it is healthy. I have some plants, too, that are said to show virus symptoms easily and decline fast and they haven't caught anything yet from the orchids. Let us hope this remains the case.

[ronaldhanko]

Fascinating thread, and I am with you in the matter, James. I am not going to start testing 200-300 plants and spending money on tests that I cannot depend on 100% anyway (it is clear from this thread that there are more viruses than can be tested for). I've grown orchids for 35+ years and started with a collection of plants most of which came from the Avril Harriman estate through his former caretaker. They included a lot of old Cymbidium hybrids and Paph hybrids. I soon saw evidence, though it was a while before I realized what was happening, that the Cymbidiums were all virused and showed the classic symptoms of the best known viruses. Eventually they all went in the trash with one exception, a plant that was not clearly and visibly virused and that was a prolific grower and heavy bloomer. I kept it for many more years. Only once, since then have I had a plant, a Masdevallia, that seemed so have something wrong with it - persistently crippled leaves and flowers. It went out also. I do not grow Phals, Cymbidiums, etc., anymore, but mostly species and odd genera at that, so perhaps the problem of viruses is not as big an issue for me, but even if I was growing those more popular genera, and growing them for my own pleasure, I would not test all my plants, nor would I worry about plants that were vigorous and bloomed well, though I would not keep a plant that was obviously and persistently "sick."

[nlm2951]

Hi, two of my catts. have some shadows on some leaves, some people told me it could be some reaction from fungicides, insecticides or water I have a GH with fan. Pls. does anyone knows about it? Thanks.......norma

[quiltergal]

Norma, can you post pictures of the affected plants?

[DavidCampen]

Originally Posted by quiltergal

... I have no intention of strip testing my plants. ... the results are inconclusive (too many false positives).

What basis do you have for making this statement? As far as I know that statement is not correct.

---------- Post added at 07:31 AM ---------- Previous post was at 07:27 AM ----------

Originally Posted by ronaldhanko

I am not going to start testing 200-300 plants and spending money on tests that I cannot depend on 100% anyway (it is clear from this thread that there are more viruses than can be tested for).

That is a strange argument - you won't do any testing since no tests will detect all pathogenic viruses. How does this validate not testing for the pathgenic viruses that can be tested for?

---------- Post added at 07:33 AM ---------- Previous post was at 07:31 AM ----------

Originally Posted by Ray

I have heard that ALL phalaenopsis plants are virused. I don't know if that's true, but it wouldn't surprise me.

Certainly every organism harbors viruses. You have to distinguish between pathogenic and non pathogenic viruses. Many phals are free of the 2 common pathogenic viruses - ORSV and CymMV.

---------- Post added at 07:36 AM ---------- Previous post was at 07:33 AM ----------

Originally Posted by james mickelso

I have had bacterial infections, fungal infections, and bugs in my collections and I am positive most were virused. But few showed any problems and except for a handful most never showed any defineable ill-effects. And I had lots of them for a long time. So I wonder, from my experience, what is the problem with virused plants to most of us who grow orchids as purely a hobby?

Are you really trying to argue that ORSV and CymMV infections are benign? If you are then I can give you lots of information to the contrary.

---------- Post added at 07:40 AM ---------- Previous post was at 07:36 AM ----------

Originally Posted by james mickelso

I have recently read a great deal on plant viruses and especially viruses that affect orchids. So I don't need to have them explained to me. Just your opinions on the threat of having a virus invading your collection.

Then you should understand that ORSV and CymMV infections are most definitely _not_ benign.

---------- Post added at 07:44 AM ---------- Previous post was at 07:40 AM ----------

Originally Posted by camille1585

...
The fact is that virus is everywhere in nature. I can across an article at work about the prevalence of virus in wild cabbage populations on the southern coast of England. 30 to 98% of the tested plants were positive of virus, with many of them positive for ALL 6 of the viruses tested for! Yet the plants are happily growing.

How does this relate to ORSV and CymMV infections of orchids? Again, if you are trying to argue that ORSV and CymMV infections are benign then I can supply lots of counter information.
---------- Post added at 07:45 AM ---------- Previous post was at 07:44 AM ----------

---------- Post added at 07:52 AM ---------- Previous post was at 07:45 AM ----------

Originally Posted by camille1585

... So virus is something unpleasant, but symptomless plants are not the end of the world for me. BUT if I were to start collecting for any of the other reasons I state above, THEN I would aggressively cull out virused, yet symptomless plants and be very demanding when purchasing plants.

The effect of the pathogenic viruses ORSV and CymMV varies by genus, species and even cultivar. A particular plant may be symptomless but it is still capable of infecting another plant that would be devestated. Also, the effect of being infected with both ORSV and CymMV appears to be more than additive, a plant that could reasonably well withstand infection with either one will be seriously affected by being infected with both.

---------- Post added at 07:57 AM ---------- Previous post was at 07:52 AM ----------

Originally Posted by quiltergal

I don't know if there is a specific test for these yet. PhCSV (Phalaeonopsis Chlorotic Spot virus) is related to INSV (Impatiens Necrotic Spot virus), but is not the same.

There are commercial tests for this virus but the simple Agdia Immunostrip test does not work, you need to use PCR amplification followed by gel electrophoresis. Agdia sells materials for this type of test.

[camille1585]

I never ever said that OSRV and CymMV viruses are benign, please don't make me say things I never wrote. I was writing about CABBAGE as an example and was simply illustrating that whether we like it or not, virus is everywhere. So chill a bit.

I think Ron sees things like I do (correct me if I'm wrong Ron). Orchids are 'just' a hobby and as long as plants aren't visible diseased and doing poorly, the viruses are tolerated. Testing everything requires too much time, effort and money. And even then, plants need to be retested in a few months to pick up any positives that may have been below the detection thresehold the first time, and confirm the positive tests. For me all that trouble is not worth it, because having a virus free collection is just not one of my priorities.

Of course there are examples of OSRV and CymMV of being very bad, I'm sure you can provide them. But until the symptoms and effects are full blown, a virused but asymptomatic plant often continues blooming and growing just fine. So that's where I understand Ron saying "What's the big deal"? Ok eventually the plant will go downhill, but I'll enjoy it until then.

I do think you're being a bit agressive about this. You don't want virus in your plants, and that's your right. I know much more about plant viruses than the average person on OB, but I CHOOSE not to make a big deal of it, because I have other things to worry about in my life, and the orchids are there to make me relax, not stress out some more. I made an educated decision to tolerate virused yet asympotatic plants in my collection. Please respect that.

[ronaldhanko]

Originally Posted by camille1585

I never ever said that OSRV and CymMV viruses are benign, please don't make me say things I never wrote. I was writing about CABBAGE as an example and was simply illustrating that whether we like it or not, virus is everywhere. So chill a bit.

I think Ron sees things like I do (correct me if I'm wrong Ron). Orchids are 'just' a hobby and as long as plants aren't visible diseased and doing poorly, the viruses are tolerated. Testing everything requires too much time, effort and money. And even then, plants need to be retested in a few months to pick up any positives that may have been below the detection thresehold the first time, and confirm the positive tests. For me all that trouble is not worth it, because having a virus free collection is just not one of my priorities.

Of course there are examples of OSRV and CymMV of being very bad, I'm sure you can provide them. But until the symptoms and effects are full blown, a virused but asymptomatic plant often continues blooming and growing just fine. So that's where I understand Ron saying "What's the big deal"? Ok eventually the plant will go downhill, but I'll enjoy it until then.

I do think you're being a bit agressive about this. You don't want virus in your plants, and that's your right. I know much more about plant viruses than the average person on OB, but I CHOOSE not to make a big deal of it, because I have other things to worry about in my life, and the orchids are there to make me relax, not stress out some more. I made an educated decision to tolerate virused yet asympotatic plants in my collection. Please respect that.

Exactly! You just said it better than I did, Camille. I don't even see the point of growing orchids as a hobby if I have to go through all the expense and time of trying to keep the collection virus free. My hobby would turn into virus testing, then, not orchid growing. And, David, no one is attacking your right to test your orchids or keep you collection virus free. Please don't be so aggressive.

[camille1585]

Originally Posted by DavidCampen

There are commercial tests for this virus but the simple Agdia Immunostrip test does not work, you need to use PCR amplification followed by gel electrophoresis. Agdia sells materials for this type of test.

Running an Elisa test is much cheaper than running a PCR and gel. And just a comment,while Agdia does sells the primers for it, it certainly is not for home use! The immunostrips don't exist yet for this virus, but a quick search of literature shows that the antiserum for it has been developped. So Elisa is possible.

[Leafmite]

I agree. I did quite a bit of asking and reading and what I learned is that it is recommended that a person is trained by someone experienced before that person begins testing plants or people for virus. If one doesn't perform the test perfectly, the results might not be perfect. Another test is always recommended to confirm results.
If a plant is vigorous, growing well, and exhibits no signs, how do you know, without an advanced test, whether something else is causing the false positive? Why toss an expensive orchid whithout certain confirmation it is virused? Why spend all that money for testing when you can just toss all the orchids and raise parakeets?
Seriously, if you observe your plants, I think it becomes clear pretty quickly if something is wrong with the plant. Buying from reputable vendors is very helpful, too.