Virus testing: What does this result mean?

[Orchidtinkerer]

this is what the instructions show on their website, if it helps at all.

It looks like the same lines have shown as in the instructions which to me look like a control line and a definite positive for CMV just underneath but they might have swapped their lines around - only the instructions with your test should be used.

I hate these strip tests to be honest, looking again I think it might be negative since I now see 4 lines, a grey line, then the control line and 2 more faint grey lines?

Wish I could borrow one of those strips for one of mine - I will just carry on being suspicious.

The rega site does confirm that virused plants grow slower than non virussed plants which is something I was never sure of.

[BrassavolaStars]

Unfortunately I am out of tests. I’ll have to wait a bit to get more as they are fairly pricey and I’m so over-budget with my greenhouse renovation.

I think that more sophisticated testing (maybe from critter creek) may be in order for this plant though. I had heard from some that an extremely faint line may be some other ailment that the strip isn’t designed for.

Here is another photo as well from a different angle. I circled the CymMV lines but the ORSV lines are also doing the same thing.

[Roberta]

I'd agree that a "second opinion" from a lab would be a very good idea. Tests are more sensitive, and more specific.

[Ispahan48]

If the faint lines on the Rega Bio tests are grey and NOT red, then I do not think they are positive tests. I think it just that whatever reactive material is in the strip is now visible because it is wet or moistened. I have noticed this same phenomenon to be a recurrent problem with the Rega Bio test strips. I don't think they are manufactured to the same standards as the Agdia strips. That said, and as others have suggested, I would retest the plants in about a year just to be certain.

[Roberta]

Actually, I think the issue with the Rega strips is that they are much more sensitive than Agdia. According the the person who arranges the group order (a biochemist who owns a company that does immunoassay work though not on orchids... orchids are a hobby but he applies the same science to those), they work on a much smaller sample even than they suggest in their documentation. (He has many miniatures, and that's one of the attractions of these strips, much less damage to the plant) He has explored the sample-size issue... finds that it can be so small that tiny samples can be used to test a group (up to about 6 plants)... if all are negative, one test covers all, if positive shows up then the plants can be tested individually. His recommendation, based on communication with the company, is that the faint line is likely a weak positive... but he has found that the low level weak response can persist over several years and not get worse in many cases, others may eventually become a definite positive.