Would this be a definitive CymMV test result? - Orchid Board

BrassavolaStars · #1 08-04-2021, 03:40 PM

Hello all,

I am very disappointed to see that this Cattleya I recently bought seems to have testes positive for CymMV.

I tested it because as they flower aged, it got a bit necrotic in a streaky way. I am guessing the the result below as definite based on how strong the lines are?

I used about an eraser end of a pencil sized piece of flower spike from an aborted bud as my test sample. The CymMV line lit up almost immediately after putting the strip in the mixture. It looks like it might have ORSV too.

It actually took a bit of time for the control line to come up but it’s there clearly now. I guess this plant lives in the virus room now. I hope it didn’t spread anywhere.

I think I have pulled a dried off sheath or two off of this plant using my hands but always washed them after. I never shared any tools with other plants and this one so I think I should be okay?

Roberta · #2 08-04-2021, 07:06 PM

Yup. Loaded with CymV. likely trace of ORSV. (Or something else... those Rega strips are very sensitive, a weak line can also be some other virus, according to the Rega technical folks) But there's nothing ambiguous about the strong line. Just keep it away from other plants, you're doing all the right things. It's a beautiful flower. And a perfect example of a situation where a casual look will miss suspicious signs, the flower and plant can look good. Testing was the exactly correct thing to do.

Note... you can cut back your sample size for future tests...The instructions are 1 sq cm of leaf (or even less works fine), the blasted bud maybe have had higher concentration. It's one of the benefits of the Rega tests vs Agdia - you don't need much sample, making it a good test for miniature plants where you could not get enough sample for a proper Agdia result without harming the plant.

BrassavolaStars · #3 08-04-2021, 08:49 PM

Quote:

Originally Posted by Roberta

Yup. Loaded with CymV. likely trace of ORSV. (Or something else... those Rega strips are very sensitive, a weak line can also be some other virus, according to the Rega technical folks) But there's nothing ambiguous about the strong line. Just keep it away from other plants, you're doing all the right things. It's a beautiful flower. And a perfect example of a situation where a casual look will miss suspicious signs, the flower and plant can look good. Testing was the exactly correct thing to do.

Note... you can cut back your sample size for future tests...The instructions are 1 sq cm of leaf (or even less works fine), the blasted bud maybe have had higher concentration. It's one of the benefits of the Rega tests vs Agdia - you don't need much sample, making it a good test for miniature plants where you could not get enough sample for a proper Agdia result without harming the plant.

I thought it was probably loaded with CymMV based on this result. This time, I used an Agdia strip and a piece of flower spike. I am pretty sad about this one as I had been looking for this clone for a long time and finally found it.

Roberta · #4 08-04-2021, 11:47 PM

Total bummer! I hope that the seller will reimburse you. The good ones do, but plenty don't.

realoldbeachbum · #5 08-05-2021, 01:46 PM

Real Bummer, Brassa.

I had the same thing happen with a new online purchase. After several emails containing pics of the strip and the plant label, I was finally reimbursed. If the grower does NOT reimburse you after seeing pics of the test strip, please let us know the identity of the grower.

SouthPark · #6 08-05-2021, 03:01 PM

Quote:

Originally Posted by BrassavolaStars

I tested it because as they flower aged, it got a bit necrotic in a streaky way.

If the flower first started out to look nice for a fair amount of time, then it might be ok - regardless of whether it has a virus or not. Some sources indicate that lots of orchids have viruses in them without anybody knowing about it, and they do just fine if provided with regular good growing conditions - even the flowers look good.

So could possibly consider what the time span is for 'flower aged'. A few days? Two weeks? Also probably depends on the environment conditions during these times --- (temperature, humidity, any water damage etc).

I'm currently growing a Ctt. Porcia 'Cannizaro', in which Roberta says that she something like all of such clones have a virus - except this plant is immune to it ----- like a 'Typhoid Mary' case. I have it growing among my other orchids - and I'm not concerned about it at all. It (the one with relatively tall bulbs) is next door neighbour to a soon-to-flower C. violacea, which can be seen at this link here.

For the case where this test for CymMV is positive ----- then ----- there certainly is the option for getting a refund - as in ROBB's case.

Leafmite · #7 08-06-2021, 02:08 AM

I am sorry to hear about the orchid having a virus. I would definitely contact the vendor to let them know (nicely). Most good vendors will appreciate the alert as they don't want the reputation of selling infected orchids.

I am one that doesn't test but if an orchid shows multiple suspicious signs, including a lack of vigor (doesn't put out the new growths or bloom at the usual time), odd leaf markings and color break (or what you have), it is removed from the collection and tossed.

If the orchid's flowers are showing issues, it is usually going to get worse in the future with deformity and mutations so you might as well see what the vendor wants to do about the orchid and, if you don't need to return it, toss it."

Some orchids are extremely resistant to virus and, with the best of care, will never show any signs but most will gradually become less vigorous over time and will eventually succumb. Some other plants have been bred to be resistant to virus. If they catch a virus, it doesn't hurt them too much. Years ago, people talked of developing resistance in orchids, too.

BrassavolaStars · #8 08-07-2021, 12:43 PM

Hello all,

I did buy this plant originally in April off of eBay. I am not going to blame the vendor too conclusively because it is possible it got infected in my care by some sort of pest (I am actually very worried about this scenario because I have 200+ plants). I would probably ask for a refund if I tested it even a month after I bought it and it came back positive but I’ve had it 4 months+ so I don’t feel like I could hold them responsible at that point. That said, I don’t know long from infection is a positive test result? If it is a year or more, then I have a case.

The flower was open for an undetermined amount of time because it was in the back of my greenhouses and I did not realize it was blooming.

It was probably blooming at least a week and a half before it got necrotic like that though because I brought it into my regular house after I noticed it blooming and it was fine for a week at least.

SouthPark · #9 08-07-2021, 04:03 PM

Quote:

Originally Posted by BrassavolaStars

It was probably blooming at least a week and a half before it got necrotic like that

Thanks for describing the observations. On the bright side of it ----- at least the flowers were nice for 10+ days.

In this paper here - they mentioned something about brown patches appearing anywhere from 5 to 21 days for cattleya flowers. Although ---- 21 days is probably getting up to the limit of the regular life-time of a catt flower ----- on average - where age-related breakdown occurs already.

If you regularly test your orchids with virus kits, and the results always came out negative ----- and if this orchid really has a virus, then we could say that the chance of the orchid being infected by your plants is maybe much smaller than the chance that it was already infected when it arrived. In that case - if already infected, then it's not fair for you (the buyer) - as you paid for the orchid!

Roberta · #10 08-07-2021, 04:16 PM

A virus like that, especially with that high of a virus titre, has been infected for a long time... probably some years. By and large, viruses are not that contagious... the orchid club member who is the expert on these (he also works in the immunoassay field, approaches everything scientifically), has done some testing - he had some seedlings that he actually tried to infect to test the infectiousness of viruses, and they have tested negative over a period of three years or so. So I don't think this is a new problem with your plant. It's worth testing those nearby, if they're negative you know for sure that the plant did not get it from other plants of yours.