# Virus testing!



## Shiva (Jul 21, 2010)

I'm curious about these virus testing kits for orchids I've seen advertised in some magazines. Has anyone tried them on large scale? Are they reliable? What's the proportion of false positives? Are they worth the trouble?


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## luvsorchids (Jul 21, 2010)

I have heard second hand from people that use them that they work well, but you also need to take into account signs and symptoms. I am not sure what the % of false positives are, but there are more likely to be false negatives because these tests measure virus antigen present depending on the stage/severity of infection, the antigen present may be below the detectable level for the test.

Susan


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## Candace (Jul 21, 2010)

From what I understand it costs around $5 for each test. So, you need to factor that in to your purchase of a plant, if you want to test all of your collection etc. If it's a $10 plant vs. is it a $300 division etc. Are they accurate? Yes.


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## chrismende (Jul 23, 2010)

I've heard that some people cut the teststrips in smaller pieces to be able to test more plants. I don't know much about it, though.


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## mormodes (Jul 23, 2010)

I have the Adgia test strips. Rememeber that these test for only 2 of the many viruses that can infect plants. They test for Cymv and OSRV. That said they do give you some sort of handle on whether a plant is virused or not. If a plant tests positive then you know its got one of the two, but not that its completely virus free. The point that you have to know the other signs of what a virused plant looks like is a good one. However you also have to know that just because a plant looks virused doesn't mean it is. Yes. Very confusing.

The solution packs have an expiration date, so don't over buy. Next time I'm going to share an order with friends. The bulk price can get down to $5 per packet.

As to ease of use after a short learning curve they are easy. The Adgia web site has videos on how to use the materials. Sometimes I've had to use more than one test strip per sample because the sample fluid won't wick up to the test area, so you waste a strip. But I got over fretting about that.

IMHO they are worth the trouble, and the only thing I do any differently would be to share an order with a friend. I have several expired packets sitting in my refrigerator that I should have used or sold. So I wasted some money.

One of the reasons why I think they are worth the trouble is because I share my orchids with my society and I'd hate to give someone a virused plant because I have a reputation to maintain. If anyone asks why a leaf tip is cut I can answer that I virus tested the plant and according to the strip it doesn't have either of the two viruses.

I have well over a thousand orchids in my collection, mostly cattleyas. No I haven't tested all of them. Only the ones I wonder about (color break or weird paterns on leaves or pseudobulbs), old classic catts, or one's I'm going to give away.

Hope this helps.


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## NYEric (Jul 23, 2010)

Virus test!? Shoot, if that sucker even looks at me wrong I'm trashing him!! :crazy:


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## tenman (Jul 23, 2010)

NYEric said:


> Virus test!? Shoot, if that sucker even looks at me wrong I'm trashing him!! :crazy:



Well, that's fine for you, but for me I'd rather check it out. I still remember a posting a few years back from someone who tested something like a dozen of her plants as an experiment, half of which she was worried might have virus from some symptoms and half which did not. Several of the ones she had had no symptoms from and were what she thought of as the control group tested positive. IIRC, only one of the ones with the symptoms tested positive. While there are viruses which are not measured by these strips, there are also other things which can cause virus-like symptoms, such as fungus, stress, chemical exposure, temperature extremes, genetic issues, etc. 

So it still comes down to a judgment call. And remember there are some folks who have what are now very rare, fine old plants in their collections known to be virused but keep them anyway for their beauty, theoretically isolated from other plants (won't get into the insect vector issue here). The virused plants have remained healthy for 40-50+ years - they just are virused but not fatally.

At this point it's not a B/W issue; I'm hoping that better testing of a wider variety of viruses will become available inexpensively but who knows? There will probably still be other viruses not tested for.

If I have a plant I suspect of virus, I test it and isolate it. If it tests negative (and all but two have - one trichopilia and one phal) I put it off to the side and watch it through a couple more growth/bloom cycles and if I see no further evidence, I don't worry about it anymore.

As they say, it's the quiet ones ya gotta watch out for - the apparently symptomless plants which may be carrying virus and spreading it without themselves showing signs until much, much later when it's already too late!


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## Eric Muehlbauer (Jul 23, 2010)

All the plants I have had that were virused..and its very few...have had minimal symptoms. The ones that really look like they could be virused have turned out clean. However, if a plant I don't really care too much about shows a mosaic pattern on the leaves, I just trash it.


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## likespaphs (Jul 24, 2010)

i don't know if it's true, but i've heard that it can take seven years for a virused plant to show symptoms


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## PaphMadMan (Jul 24, 2010)

likespaphs said:


> i don't know if it's true, but i've heard that it can take seven years for a virused plant to show symptoms



A virused plant can show symptoms in just days if actively growing tissue is infected, or may never show symptoms at all, ever. 7 days... 7 years... 70 years... all possible.


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## likespaphs (Jul 24, 2010)

really? 
crazy.


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