# C. Harold Carlson ‘Linwood’



## southernbelle (Nov 4, 2020)

Bummed! I purchased this nice division in bloom (2 flowers) Aug. 2019. It just bloomed for me with 5 flowers. I tested it for virus a couple of weeks ago because of streaking on a leaf and!!!! It’s positive for OSRV!!!! Since it was in spike I decided to isolate it and let it bloom. Here is the comparison:
First photo is 8/19. The rest are today. 5 large flowers but color break on some. Another one I must trash It’s better to know now before it infects others but #%#%! Ive got to diligently test everything now.


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## SouthPark (Nov 4, 2020)

Deepest sympathies SB!!!

On the other hand, I just remember that the world and universe is forever changing. Things can diversify - and change. So regardless of orchids having virus etc, some of them may be immune and adapt ----- and so the orchid family can become stronger if some virused orchids are left to survive.

I (like a lot of people) grow Ctt. Porcia 'Cannizaro' ..... a different hybrid catt, and there is a mention that they (Ctt. Porcia 'Cannizaro') are *all* virused - every one of them.

I grow mine anyway, and it is parked up among all my other catts and orchids. I haven't had colour breaks on any of my orchids or any weird stuff happening to their leaves and growth behaviour ------ so have been lucky over all these years.

Even though I know that insects etc can hop from 1 plant to another etc, I still do certain things (eg. no water sharing, no touching 1 plant and then touch another etc), and I don't re-use my scoria media until after I boil it and then dry it out in the sun etc.

Also, interestingly - and not sure how they actually know ------ but there is mention that there are no reported cases of wild orchids having virus. Quite interesting.

Also ----- SB - with your orchid, it's hard to say whether your orchid had it first, or whether it got infected by one of your other ones.


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## southernbelle (Nov 5, 2020)

SP I am aware that many, if not all, old types are virused. Waldor talks about their group of those on their website. 
Secondly, although I have been reasonably careful (I never make a cut on more than one plant without disinfecting clippers, stakes etc. (TSP), I repot on clean newsprint and disinfect pots. Never re-use media. Disinfect sink, drain board, tray, etc. after repotting. Having grown roses for years I was aware of not spreading virus, etc. My only vulnerability is when I water, I put them on a drain board before back in the trays and the run off potentially could spread infection, I have learned. So far, I’ve found 5 virused plants out of 100. 1 from Lowe’s, 2 from a local vendor, 1 from HI vendor and a seedling. Chances are the seedling was cross contaminated which is what had caused me to begin trying to check everything. It is possible, of course, that the ‘Linwood’ was cross-contaminated as well. it’s from a local vendor a year ago who has said they don’t worry much about virus unless there are visible signs. 
I just experienced another frustration in that I ordered the 25 test kit bundle from Agdia fir CymMV and ORSV. I did not notice until I had tested 4 plants (all negative with very light control lines) that they sent the wrong tests!! These tests are for Impatiens virus INSV!!! I’m sure they will take care of it, but I have to retest those plants now. Lessons learned. I will, certainly, test any new plants purchased (when they arrive) in the future. And slowly go though my others.


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## SouthPark (Nov 5, 2020)

Thanks for your post comments SB! Your 'Linwood' flowers are incredibly beautiful. Also unbelievable how that supplier sent the wrong test kits! Those amateurs!!!! Geez.

One other nice hope is that - maybe one day somebody or some group can come up with a cure ------- which also brings up the question of ----- I wonder if (*?*) any group of people, anywhere in the world has actively been seeking or continually attempting to develop a cure for these viruses in orchids and other plants. That would be awesome if some people are doing something in this area.


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## southernbelle (Nov 5, 2020)

Update: I spoke to Agdia and they are replacing my kits with the correct ones. If anyone can use some kits for Impatiens Virus (INSV) they are yours. 
I was talking to technical people and asked about combining up to 5 samples in one test as was mentioned on a previous thread. He said that it can be done as long as the combined samples do not exceed ¾” square which is the recommended sample size for test accuracy. HOWEVER, he pointed out that the chances of false negative are high, because if 1 of the 5 happened to be infected the viral load would be low due to the smaller (1/5 of 3/4”) size of that plant’s sample. The test is designed to perform to pick up a viral load in a ¾” sample of one plant. Makes sense.


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## PeteM (Nov 12, 2020)

Thanks for this post. With a very heavy heart I also tossed 7 plants and pots from my collection this past month, which tested positive. All of them were new plants purchased in the past year, when I ran out of virus test kits. I ALSO really need to do a better job testing plants before they enter the collection. I was shocked by the rate, but as I become more interested in choice plants, buying divisions seem unavoidable. Lesson learned. I also contacted one of the prominent vendors to inform them that their mother plants were likely positive. They were very appreciative of the information. 

I'm going to bring up burning clippers again. Chemicals may not get to all the plant material. I know you mentioned not liking the way the clippers look after burning them. From my perspective this might be the highest amount of risk I see in your routine, you are putting a lot of your time and resources into this firewall. Maybe purchasing some inexpensive steel bonsai or detachable culinary scissors that you can rotate out every few years for this purpose. I've seen a presentation of a grower in Asia, had a greenhouse full of Vandas. Each Vanda had a rope attached to the hanger, and each rope had a pair of dedicated scissors tied to the other end of the rope. The grower found that isolating each plant with a dedicated pair of scissors was cheaper than sharing the shears and having to test all his plants. 

Burning is very quick and easy as it is ready to go with the flick of the button and you don't need to mix up solution every-time to make sure the chemical solution is still potent enough. Below is the link to one of Keith Davis's 3 part series, maybe you are familiar with these.. it's a long presentation, minute 34 of this link is where he discusses mapp gas, benefits over propane, right after he talks about virus testing.


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## SouthPark (Nov 12, 2020)

So are there any groups out there that are actively working toward developing cures for these viruses? That would be awesome.


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## PeteM (Nov 12, 2020)

SouthPark said:


> So are there any groups out there that are actively working toward developing cures for these viruses? That would be awesome.



Actually, one of the Odoms YouTube cattleya symposium presentations Jeff Bradley or someone talks about this. I can’t recall which presentation. But it’s an open discussion on a new process that reduces the virus in the plant available in Germany?. Mentioned it costs 10s of thousands of dollars. One audience member suggested collectively raising funds to have the procedure to resurrect some of these older choice historically important virused plants. This was back in 2015-2016... not sure where this technology is now.


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## monocotman (Nov 12, 2020)

Cures at pretty much impossible at a technical level. The viruses are within the cells and some can be inserted into the genetic code.
one way I heard of eliminating viruses was to do some careful tissue culture of the apical meristem. This area of the plant has lower levels of virus as it is the place where new cells are being created through division and the viruses have not had time to infect them.
It may be that you need to go through this process several times, each time growing the meristem for a period to get it to a decent size.
so its along winded process with no guarantees! Not for the faint hearted.


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## terryros (Nov 12, 2020)

Deborah and I have been communicating about this topic a fair bit and I have been ignoring viruses too much. It seems obvious that a mericlone made from an infected plant stands a very high chance of being infected. What happens if a diseased plant is used as either the pod or pollen plant in a cross? I can imagine that a diseased pod parent might more easily pass the virus to seeds? Maybe being the pollen parent avoids some virus in a cross? Maybe virus is even passed with the germ cells? Since so many of my plants were purchased as young seedlings, I may have mistakenly assumed that they would be virus free.

Too many questions but I have to get serious about this issue. My test kit order is being shipped now.


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## southernbelle (Nov 12, 2020)

PeteM said:


> Thanks for this post. With a very heavy heart I also tossed 7 plants and pots from my collection this past month, which tested positive. All of them were new plants purchased in the past year, when I ran out of virus test kits. I ALSO really need to do a better job testing plants before they enter the collection. I was shocked by the rate, but as I become more interested in choice plants, buying divisions seem unavoidable. Lesson learned. I also contacted one of the prominent vendors to inform them that their mother plants were likely positive. They were very appreciative of the information.
> 
> I'm going to bring up burning clippers again. Chemicals may not get to all the plant material. I know you mentioned not liking the way the clippers look after burning them. From my perspective this might be the highest amount of risk I see in your routine, you are putting a lot of your time and resources into this firewall. Maybe purchasing some inexpensive steel bonsai or detachable culinary scissors that you can rotate out every few years for this purpose. I've seen a presentation of a grower in Asia, had a greenhouse full of Vandas. Each Vanda had a rope attached to the hanger, and each rope had a pair of dedicated scissors tied to the other end of the rope. The grower found that isolating each plant with a dedicated pair of scissors was cheaper than sharing the shears and having to test all his plants.
> 
> Burning is very quick and easy as it is ready to go with the flick of the button and you don't need to mix up solution every-time to make sure the chemical solution is still potent enough. Below is the link to one of Keith Davis's 3 part series, maybe you are familiar with these.. it's a long presentation, minute 34 of this link is where he discusses mapp gas, benefits over propane, right after he talks about virus testing.



Thanks Pete! I actually heard Keith at VOS speak of this and bought a mapp cylinder. I just communicated with Jerry Fisher about this and he also uses mapp gas to sterilize cutting tools. At 1,000 degrees a quick pass will kill anything. (Viruses die at 250 degrees). I held my blade in the flame for at least 5 seconds so that’s why my clippers were negatively affected (and stayed hot!!)
Jerry talks about using a product that kills everything, very effectively. I’m exploring it now and will report back (and with his permission will share). Stand by. See update below.


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## SouthPark (Nov 12, 2020)

monocotman said:


> It may be that you need to go through this process several times, each time growing the meristem for a period to get it to a decent size.
> So its along winded process with no guarantees! Not for the faint hearted.



Oh geez. True MM. It would be a long road for sure. Just raising certain orchids from seeds to flowering size could take maybe a significant fraction of our life span hehehe. This particular method of obtaining virus-free orchids from virused ones could take ages for sure. Still quite a useful technique if it does result in plants with no-virus though. That would be awesome. At least it's progress.


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## southernbelle (Nov 12, 2020)

Jerry talks about using a product that kills everything, very effectively. I’m exploring it now and will report back (and with his permission will share). Stand by.

UPDATE:
I received permission from Jerry Fischer to share this info. Sounds very encouraging to me:

"The only way that the viruses can pass on is through cutting tools, used pots or hands that have virus on them. We sterilize most everything with flame Map gas is probably over 1,000 degrees so the sterilization is pretty instant. These viruses die at 250 degrees after 15 minutes exposure at that temperature. A torch is way hotter. Plants that might drip on each other won't necessarily always spread virus, it's not been proven yet but it is possible.
We have been using a product called PronTech which is a type of dimethyl ammonium chloride laced with urea. When you spray or treat the whole plant with it at 800 PPM in the early AM it is absorbed through the cell walls and stomata. It then attacks everything in the cell except the nucleus. We have been able to freeze or reverse the virus in several plants with two or three treatments about 2 weeks apart. It doesn't always work 100 percent but it does on a number of things.
PronTech is sold by a company called United Products International or UPI. PronTech is used to control biofilm and was the most important thing used to battle the bird flu. It is used in dairy operations to clean pipes and sterilize things. The owner who is from Columbia has told me some stories of the product's efficacy which are pretty amazing.
We treat all incoming plants with it as soon as they arrive."

I have ordered it (I could only find it on this one website). I don't know that I will use it to try and reverse virus unless it is a special plant, but as a disinfectant it sounds like there are not many better. PRONTECH 1Kg - Dose: 2g / 1 Liter of water = 500 Liters of Disinfectant


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## Ozpaph (Nov 13, 2020)

interesting discussion, thank-you


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## Ray (Nov 13, 2020)

If you want to kill viruses on surfaces and tools, Physan 20 is quite effective. In fact, almost any quaternary ammonium compound is effective.

While I’m not saying “no way!”, I have a hard time accepting that a product sprayed onto a plant kills viruses.


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## SouthPark (Nov 13, 2020)

Ray said:


> While I’m not saying “no way!”, I have a hard time accepting that a product sprayed onto a plant kills viruses.



True Ray. Because the spray won't reach everywhere on the plant - including down in the media or roots area etc - including every little external part of the plant. This is assuming that the virus hasn't got inside the plant.


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## tomp (Nov 13, 2020)

Regarding a cure: I understand that dry seed propagation does not transmi virus to new plants. If true is a long wait but for a seriously good plant..

regarding sterilization of surfaces: Vikron S seems to be very effective and affordable.


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## monocotman (Nov 13, 2020)

Ray,
I agree with you, killing a virus with a spray sounds very far fetched.
It would need to get into every cell in the plant. Very unlikely,
David


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## southernbelle (Nov 13, 2020)

SouthPark said:


> True Ray. Because the spray won't reach everywhere on the plant - including down in the media or roots area etc - including every little external part of the plant. This is assuming that the virus hasn't got inside the plant.


This all is certainly way over my head, but he did say that it penetrates the cell wall and stomata attacking every thing in the cell except the nucleus. And, has efficacy in some of the plants he has used it on. He is credible and has no reason to exagerate. He does not sell the product. He just shared his experience with me and gave me permission to share it here.


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