Virus testing on Cattleyas

[southernbelle]

Snow in March in Virginia crazy just crazy. Is it snowing in spotsy?
PatrickView attachment 32927

Yep, about the same amount as you.

 

[NEslipper]

I just went through a batch of 25 Agdia strips to test all my old, heirloom cattleyas. I haven’t tested any seedlings yet, but those are relatively low risk as they’ve been purchased from Orchids Limited, SVO, and Steven Christoffersen. In terms of the old timers, 2 out of 25 were virus positive, 1 ORSV and 1 CymMV. The two virus positive plants are the oldest plants in my collection, so it’s not surprising they contracted viruses in 100+ years of culture. I had already been growing them in an entirely separate room from the rest of my catts out of an abundance of caution. The ORSV positive plant I will likely discard, but the CymMV+ plant is one of my most vigorous growers and bloomers - the leaves and flowers are immaculate, not a blemish to be found. It has so much sentimental value, I could never part with it. All of my “ugliest” looking plants in terms of blemishes and streaks tested negative, emphasizing that you really can’t know until you test. All my plants from Chadwick’s, Waldor, and the Orchid Alley were negative.

 

[Carmella.carey]

H

I just went through a batch of 25 Agdia strips to test all my old, heirloom cattleyas. I haven’t tested any seedlings yet, but those are relatively low risk as they’ve been purchased from Orchids Limited, SVO, and Steven Christoffersen. In terms of the old timers, 2 out of 25 were virus positive, 1 ORSV and 1 CymMV. The two virus positive plants are the oldest plants in my collection, so it’s not surprising they contracted viruses in 100+ years of culture. I had already been growing them in an entirely separate room from the rest of my catts out of an abundance of caution. The ORSV positive plant I will likely discard, but the CymMV+ plant is one of my most vigorous growers and bloomers - the leaves and flowers are immaculate, not a blemish to be found. It has so much sentimental value, I could never part with it. All of my “ugliest” looking plants in terms of blemishes and streaks tested negative, emphasizing that you really can’t know until you test. All my plants from Chadwick’s, Waldor, and the Orchid Alley were negative.

How old were these "old timers"?

 

[NEslipper]

The oldest are species trianaei that were ripped from the jungle in the late 1800s. The majority are more recent hybrids from the 1930s and 1940s.

H
How old were these "old timers"?

 

[southernbelle]

I just went through a batch of 25 Agdia strips to test all my old, heirloom cattleyas. I haven’t tested any seedlings yet, but those are relatively low risk as they’ve been purchased from Orchids Limited, SVO, and Steven Christoffersen. In terms of the old timers, 2 out of 25 were virus positive, 1 ORSV and 1 CymMV. The two virus positive plants are the oldest plants in my collection, so it’s not surprising they contracted viruses in 100+ years of culture. I had already been growing them in an entirely separate room from the rest of my catts out of an abundance of caution. The ORSV positive plant I will likely discard, but the CymMV+ plant is one of my most vigorous growers and bloomers - the leaves and flowers are immaculate, not a blemish to be found. It has so much sentimental value, I could never part with it. All of my “ugliest” looking plants in terms of blemishes and streaks tested negative, emphasizing that you really can’t know until you test. All my plants from Chadwick’s, Waldor, and the Orchid Alley were negative.

You were fortunate they have been separate and have not cross infected any others. It speaks of your good habits.

 

[NEslipper]

Thank you. I feel confident in my abilities to keep them separate, and that level of risk is acceptable to me. What I struggle with is the things I can’t control, like pests. Even with quarantining new plants, and preemptively treating, I did have a thrip outbreak this past year. It’s possible they came in through an open window or some other means, so the origin of the outbreak is unknown. They left my cattleyas alone, and thankfully it doesn’t seem any cross-contamination occurred, but even with constant vigilance these things can happen. For now I still plan to keep the infected plan, but I will reassess periodically.

You were fortunate they have been separate and have not cross infected any others. It speaks of your good habits.

 

[Carmella.carey]

Hi Deb,
Do you know any thing about tabaco mosaic virus?
My dad smokes and I wonder if that smoke could drift into the greenhouse and infect the plants.
Patrick

 

[southernbelle]

Patrick:
I do remember reading something about it back when I investigated this. I’m not sure it mentioned the smoke, but I think it was referring to it spreading to plants from the hands of smokers. Could it be on things a smoker touches and transfer? I don’t know. Google it or search AOS for it. I found this article about TMV on orchids (and spread between orchids) but not about how they can get it in the first place.
https://ipm.illinois.edu/diseases/rpds/614.pdf

 

[southernbelle]

Carmella.Carey
I found this. No to smoke spread, yes to anything a smoker’s hands have touched (after they have touched tobacco products). Virus lies dormant on everything inorganic for a very long time (years?) and can be picked up and spread to plants by touch. Don’t forget about nicotiana and other type garden plants, if planting or growing those.
https://extension.psu.edu/tobacco-mosaic-virus-tmv

 

[southernbelle]

Carmella.Carey
I’ve been thinking about this… Agdia’s Immunostrip for Orchid viruses only tests for CymMV and ORSV which are the two most common viruses to attack orchids. They do have a separate Immunostrip for TMV that tests for almost 300 strains but it doesn’t say specifically TMV-O which is the one orchids can get. One of the articles mentioned something about the way cigarette tobacco is processed it makes it less likely to carry it, I think (don’t know if it was one I sent link to.)
And, Agdia’s Immunostrip for TMV cross-reacts with ORSV so you could get a false positive if the plant was infected with that. Curiously enough their test for CymMV and ORSV does not cross-react with TMV…
Since you have decided not to test beyond what you have and only destroy plants that don’t grow well or show signs of virus, frankly, I wouldn’t worry about it.
On the other hand, if you have a plant that is important to you and it’s negative for the first two (with symptoms), you could then test for TMV knowing there would be no cross-reaction since you have ruled out ORSV. Just a thought, but if you are going to destroy the plant anyway because of symptoms, then don’t waste the $$.

 

[Carmella.carey]

Well Deb my mom is vary happy that if I ever decided to use any tobaco product I would be infecting my whole collection so as long as I have orchids (or really any plants) I will not be able to smoke.
Patrick