2 plants tested virus positive. What to do in my grow area now?

[sewagner86]

Hello!

I had 2 cattleya orchids (rustic spots and akas art) from the same grower test positive for Cymbidium Mosaic virus and then one of them also tested positive for odentoglosum ring spot virus. I am newer to orchids and this is the first time I have had virused plants that I am aware of. There was one other I was a little worried about but it came back negative. It was one I have had for a year now and its from a different place. Of course, I threw away the 2 virused plants but me being novice to this stuff, some of my other orchids were close by.

The akas art I had thought had some type of rot originally, in particular black rot. One of the psuedobulbs went squishy so I cut it off and treated the rest of the plant with a fungicide. Well, then it developed black splotches on the leaves right in the middle. When the psuedobulb went squishy, I treated the rest of my collection with the fungicide also and isolated the offender. The rustic spots I honestly thought was adjusting. It was in general population until yesterday. The big vein down the leaves were a brownish color. I don't know why I didn't think this super odd before, but oh well. That was literally the only thing wrong.

So now, the question is, do I need to do anything in my grow space since these were positive? None of my other plants appear symptomatic but I know you truly don't know. I did let the grower know and she said she has heard no other complaints. Do I need to change my isolation habits on new purchases (isolate for a month maybe longer)? What do you all recommend? I don't want to lose my entire collection to something I could have prevented.

[Roberta]

As long as you maintain good hygiene... sterilizing tools and cleaning surfaces when repotting, you're probably ok. If other plants were touching the virused plants, maybe keep them away from the rest of the collection for awhile. But if plànts don't share juices dànger is fairly low

[katsucats]

From my experience, virused plants could live side by side without co-infection if there isn't a bad spider mite or thrip infestation and the leaves aren't brushing up against each other. With that said, the recommended precautionary measure would be to virus test all the plants in proximity. I don't think longer isolation is foolproof. I personally test the vast majority of my plants immediately upon receipt (or soon after), and the majority of virused plants I've found are asymptomatic or they're very subtle that the experts on these sites would say something like "oh, that's just cold damage" or mag deficiency or whatnot. Virused plants in good care sometimes resist blemishes for a long time. It might help to purposely stress the plant by withholding watering, etc., if you could stomach it, but it still wouldn't be reliable in my opinion. I think I read a study somewhere that said virused plants resist stress better than healthy plants, it's an evolutionary adaptation to help the viruses stick around longer.

For most growers what Roberta suggested would be just fine. I'm a bit neurotic so I test every plant (factor about an extra $5 average into the cost of every plant at purchase) and isolate or toss ones that consistently have suspicious markings regardless of whether they test positive. Barring that, you won't "truly know", but that's a personal calculation most people live with.

[Jmoney]

I second katsukats, I test everything and most of my positive tests have been in completely normal-appearing plants. I have a small space so most of them get tossed, a few make it to a small external area. I am testing the whole collection, (batch-testing with 6-8 samples per bag) and have had a small number of positives which is unnerving given their prior negative testing.

[sewagner86]

Out of curiosity, which test strips do you all use and which seems easier to get? I had the agdia test strips, but if there is something out there a little cheaper, that would be nice. I don't want to bring anymore into the collection without testing and/or super close observation.

[Roberta]

Originally Posted by sewagner86

Out of curiosity, which test strips do you all use and which seems easier to get? I had the agdia test strips, but if there is something out there a little cheaper, that would be nice. I don't want to bring anymore into the collection without testing and/or super close observation.

I like Rega from Taiwan. Chraper, much more sensartve... see my comments earlier in the thread.

[Dalachin]

I use agdia just because they were easier for me to get, and I batch test groups of 4-5 plants at a time. It’s an off-label method, but in my limited experience (2 positives out of perhaps 50 tested plants) it seems to work… the positive showed up in the group test, then I had to test individuals to determine the positive plant.

[Roberta]

The only downside of the Rega tests is that the minimum order is 50. But on the other hand, if you can put together a group order (such as with an orchid society) you can get some nice price breaks if you can order multiple boxes.

[sewagner86]

I get the whole not sharing juices thing, but I worry now about getting new stuff and potentially not knowing it's diseased/virused until it potentially spreads and wipes out my collection. My plants also seem to be pretty sappy lately. Lordy, I was thinking about how much I have spent on my orchids and I cringed when I thought about losing them lol.

Anyway, I have over 60 plants, and I might see if my orchid friend would be interested in splitting a box and I can group test and maybe have a few left for new purchases. I have used the agdia tests but I wasn't sure if there was anything any cheaper.

[Roberta]

Originally Posted by sewagner86

Anyway, I have over 60 plants, and I might see if my orchid friend would be interested in splitting a box and I can group test and maybe have a few left for new purchases. I have used the agdia tests but I wasn't sure if there was anything any cheaper.

I looked it up on the Rega Biotechnology site, $200 (USD) for a box of 50 which comes out to $4 per test (plus shipping) I don't know what Agdia is charging these days... last time I tried to check the website they wanted me to set up an account first, to even get a quote. Along with high sensitivity (on a small sample, great for small plants) another benefit of the Rega tests is shelf life, which is officially 18 months, without refrigeration (and I have found them to still be good - based both on control line and verifying on a known virused plant - for a couple years after the printed expiration date.) Unless they've changed, Agdia quotes 1 year, and after expiration date I found them to indeed be "expired". And they have to be refrigerated. I think the difference is packaging. The Agdia tests come in a sealed tube with all the strips, and once you open it, moisture can get in - which is the enemy of all immunoassay type tests. The Rega strips are individually packaged, and each package also contains a silica gel desiccant. So they're protected from atmospheric moisture until they're used.