Virus Testing

[isurus79]

I tested a few of my plants for virus and got a bit of a surprise in my first try! Anyone else do a virus test and get surprising results?

https://youtu.be/2ApD18Lwiew

[Toadwally]

Originally Posted by isurus79

I tested a few of my plants for virus and got a bit of a surprise in my first try! Anyone else do a virus test and get surprising results?

https://youtu.be/2ApD18Lwiew

Yep. Seemingly flawless plants tesring positive, and other plants withs suspicious symptoms test negatively repeatedly. I'm testing only for the two main viruses.

[Bayard]

Yes, after seeing color break in a Cattleya intermedia it tested positive for one of the viruses. I started doing some more testing and found some of my treasured plants tested positive as well. All got trashed.

[Roberta]

Originally Posted by Toadwally

Yep. Seemingly flawless plants tesring positive, and other plants withs suspicious symptoms test negatively repeatedly. I'm testing only for the two main viruses.

Same here. I generally don't test unless there is something suspicious about a plant - failure to thrive, concerning patterns on leaves, color break on flowers (especially on Catts) I have not found a lot of virus problems - growing outside with lots of air circulation around plants and few bug problems helps. But there are some... Of course the classic is Ctt. Porcia 'Cannizaro' ... plant is vigorous, no color break on flowers, but this cultivar has been known to be virused for years. (The original FCC was virused, and it has manifested itself in the mericlones taken from that.) I grow it in an area well away from the rest of my collection. And, along with producing copious blooms in the fall, is very handy for testing my test kits. I use the Rega kits from Taiwan, which don't need refrigeration and have an 18-month shelf life (Agdia is 12 months, and because of the way they are packaged, that's pretty accurate) . But I don't use them all that fast, so it's good to know if a past-expiration strip is still good. There's the test line for sure. But beyond that, just to be sure, I test a sample of the plant now and then. And I have found that those Rega Agitest test strips are good even 2-3 years past expiration. (Yup, plant is still virused...) The difference is that the individual strips are in sealed packages - moisture is the enemy of the tests, and the Agdia strips are packaged with multiple strips in a little tube. So once open, there is air exposure that can't be avoided.

[katsucats]

Except for several (out of laziness), I've tested every single plant that comes into the house, and I've gotten in my opinion an unacceptable rate of virused plants from vendors everyone else think are A+. The vast majority of virused plants have no symptoms, at least for a while. Some suspect plants are surprisingly virus free. If I only tested ugly plants, I would have missed most of the virused ones.

I've actually gotten tired of buying test strips and tossing plants that I'm now only buying flasks and plants from select vendors that I haven't gotten viruses from. In my experience, that's a handful out of dozens. I hate to be like chicken little sounding the alarm. I've seen members in this forum buy plants from the same batch (even mericloned ones) and vendor that I tested positive from, showing off how healthy their plants looked, and I couldn't do anything but cringe. It's gotten a bit stressful, so my solution is that I simply stop buying plants from the majority of vendors. Not even exaggerating. I'm afraid of going to orchid shows from the PTSD of seeing those test strips and the fact that I know most people don't test.

[isurus79]

Originally Posted by Toadwally

Yep. Seemingly flawless plants tesring positive, and other plants withs suspicious symptoms test negatively repeatedly. I'm testing only for the two main viruses.

Sounds about right! I'm tossing mine that test positive.

Originally Posted by Bayard

Yes, after seeing color break in a Cattleya intermedia it tested positive for one of the viruses. I started doing some more testing and found some of my treasured plants tested positive as well. All got trashed.

Ugh, that must have been really frustrating! I'm just getting started on my virus testing journey and I hope I don't lose too many plants.

Originally Posted by Roberta

Same here. I generally don't test unless there is something suspicious about a plant - failure to thrive, concerning patterns on leaves, color break on flowers (especially on Catts) I have not found a lot of virus problems - growing outside with lots of air circulation around plants and few bug problems helps. But there are some... Of course the classic is Ctt. Porcia 'Cannizaro' ... plant is vigorous, no color break on flowers, but this cultivar has been known to be virused for years. (The original FCC was virused, and it has manifested itself in the mericlones taken from that.) I grow it in an area well away from the rest of my collection. And, along with producing copious blooms in the fall, is very handy for testing my test kits. I use the Rega kits from Taiwan, which don't need refrigeration and have an 18-month shelf life (Agdia is 12 months, and because of the way they are packaged, that's pretty accurate) . But I don't use them all that fast, so it's good to know if a past-expiration strip is still good. There's the test line for sure. But beyond that, just to be sure, I test a sample of the plant now and then. And I have found that those Rega Agitest test strips are good even 2-3 years past expiration. (Yup, plant is still virused...) The difference is that the individual strips are in sealed packages - moisture is the enemy of the tests, and the Agdia strips are packaged with multiple strips in a little tube. So once open, there is air exposure that can't be avoided.

I got the tests from Taiwan as well. I wish they were cheaper!

Originally Posted by katsucats

Except for several (out of laziness), I've tested every single plant that comes into the house, and I've gotten in my opinion an unacceptable rate of virused plants from vendors everyone else think are A+. The vast majority of virused plants have no symptoms, at least for a while. Some suspect plants are surprisingly virus free. If I only tested ugly plants, I would have missed most of the virused ones.

I've actually gotten tired of buying test strips and tossing plants that I'm now only buying flasks and plants from select vendors that I haven't gotten viruses from. In my experience, that's a handful out of dozens. I hate to be like chicken little sounding the alarm. I've seen members in this forum buy plants from the same batch (even mericloned ones) and vendor that I tested positive from, showing off how healthy their plants looked, and I couldn't do anything but cringe. It's gotten a bit stressful, so my solution is that I simply stop buying plants from the majority of vendors. Not even exaggerating. I'm afraid of going to orchid shows from the PTSD of seeing those test strips and the fact that I know most people don't test.

Yikes! I hope my favorite vendors aren't on that list!

[Roberta]

Originally Posted by isurus79

I got the tests from Taiwan as well. I wish they were cheaper!


(

A way to get the best possible price from Rega is to put together a group order from your society or maybe more than one. I got mine as part of a group order which was big enough to max out the price break.

If you find that most of the plants you test are clean, you can "gamble" a little by combining bits of up to 5 plants. (so that you end up with the amount of material that you'd use for 1 test... don't overload the test or you may get false positives) The tests are very sensitive so reducing sample size will still work. Of course, if you test 5 in one test and you get a positive, you have to go back and test the individuals. So it depends on whether or not you have a significant number of positives. And keep one of those positives around (isolated) to QC your test strips after they expire... they stay good for a long time but you need to check now and then.

[isurus79]

Originally Posted by Roberta

A way to get the best possible price from Rega is to put together a group order from your society or maybe more than one. I got mine as part of a group order which was big enough to max out the price break.

If you find that most of the plants you test are clean, you can "gamble" a little by combining bits of up to 5 plants. (so that you end up with the amount of material that you'd use for 1 test... don't overload the test or you may get false positives) The tests are very sensitive so reducing sample size will still work. Of course, if you test 5 in one test and you get a positive, you have to go back and test the individuals. So it depends on whether or not you have a significant number of positives. And keep one of those positives around (isolated) to QC your test strips after they expire... they stay good for a long time but you need to check now and then.

Luckily, I got mine in a group order.

[DirtyCoconuts]

sucks

i am aware of viruses but i have tested three plants that all looks super weird and they were all negative.

i grow outside and dont sell ay plants so whatever happens, happens

[estación seca]

I have read the majority of commercial outdoor landscape plant cultivars, and most house plants, are virused. They don't show symptoms. Most landscape and house plants are propagated via meristem or cuttings, with some of annual and perennial herbaceous plants propagated by seed. Mericloning and cuttings/bud grafting are much faster for bringing herbaceous and woody plants, respectively, to market.

Autopsy studies have shown almost all humans have herpes virus permanently in nerve cell bodies in our trigeminal nerve ganglions inside our skulls. That virus is what causes cold sores on the face. If the virus is in nerve cell bodies that innervate the eye, severe corneal damage can occur from cold sores on the eye. On rare occasion herpesvirus can infect the brain, causing severe permanent brain damage or death. Further studies have shown people usually acquire the virus in childhood, probably from kissing adults who are shedding virus though not having cold sores. Many people never get cold sores even though they have the virus in their ganglia. Should we test everybody? Then what?

With proper plant husbandry virus won't be transmitted by the gardener. But bugs can transmit virus when biting a virused plant, then biting a non-virused plant. It is possible to build and maintain bug-proof greenhouses, but it is very expensive. The ongoing rituals needed to prevent introducing bugs are cumbersome.

Commercial tobacco products all contain tobacco mosaic virus. Tobacco mosaic virus can infect orchids. The virus is not reliably neutralized by hand washing. It has been shown people who handle cigarettes can easily transmit this virus to plants they touch. It is likely orchid keepers who smoke have infected most or all of their collection with this virus. Now what?

I'm troubled at the thought of completely losing beautiful old clones of plants that are virused but without symptoms. These plants may be used as pollen parents without transmitting the virus. I have read some commercial growers keep a separate greenhouse for valuable old breeding clones that are virused.

Does it really make sense for a hobbyist to spend a lot of money on virus tests, then discard valuable plants that show no signs of illness?

In theory viruses in orchids might be eliminated if all orchid growers in the world were to test every plant, over a relatively short period of time, then burn infected plants. This would be immensely expensive and will never happen.

Experience with other infections diseases shows testing and elimination will never work. Not even trying to destroy every orchid in cultivation would work. The same viruses that infect our orchids infect many other plants, and they will return.

The isolate and burn approach was tried in the Miami area in the early 2000s to eliminate the newly introduced citrus greening disease. Officials broke into people's gardens and pulled out all citrus trees, symptomatic or not. They went as far as killing one homeowner who tried to prevent the trespass. There was no effect on the spread of the disease, which now is in every citrus producing State in the US.

If commercial growers took effective steps to eliminate completely virus for which testing exists from their stock, and prevent virus from being reintroduced, the price of our hobby would skyrocket, and nobody would be able to afford orchids. The hobby would disappear.

We can only test for a few viruses. It is likely there are many other orchid viruses infecting plants with no signs of disease. This is the situation in other organisms. Every time a new test were introduced growers would have to go through the very expensive process of culling healthy but virused plants again.

I think for the vast majority of hobbyists, testing and destroying virused but otherwise healthy plants isn't necessary. A systematic effort to remove viruses from orchid collections would be impossible. The attempt would inevitably lead to nobody growing orchids.