Virus Report-Many Virused Orchids
 

Hello everyone,
Tragedy has struck my greenhouse.
A few years ago, I decided to have 6 of my orchids virus tested by Critter Creek. Test results-some virused, some not- with either CymMV or ORSV-or infected with both. After researching more, I decided to keep the virused ones that seemed to perform well and continue to disinfect my tools, etc. -more diligently than I had in the past. Again-that incident happened a few years ago.

I decided to test again just recently and rec'd the virus test report from Critter Creek today. I was horribly surprised at the test results. Of my entire collection of 60 plants that were tested, 52 were infected with either CymMV or ORSV-or with both. Before I sent samples for testing, I had definitely decided that I was not going to keep ANY virused plants this time. Even though the test results were so awfully negative, I still do not want virused orchids in my greenhouse anymore. I understand that a 100% orchid virus test does not exist, but I want to feel that I've done the best I can do. I really, really hate to discard so many orchids, but I feel that I should this time.
I would very much appreciate your input, but my question to you is how do I disinfect my entire greenhouse...or is it common practice to do so after clearing out virused plants?
Thank you so much for reading my "book" and for the advice that I hope I receive from you.
Vicki
P.S. Words for today (and everyday)-
"DISINFECT RELIGIOUSLY

Vicki: quick question; are you growing plants to show or propagate, or just for enjoyment?
Adam

stonedragonfarms
 

hobby-enjoyment only





---------- Post added at 12:13 AM ---------- Previous post was at 12:00 AM ----------

Adam,
Why do you ask?
Vicki

There's quite a few "old" plants that are known/accepted to be virused in classic cattleya stock; I thought that if you were focusing on plants for your personal enjoyment as opposed to showing/selling/passing along, it might be just as well to simply enjoy them as they are--warts and all. I'm not sure as to the size of your greenhouse, but if your collection is on the small side, I think I would just discard plants that are showing signs of virus (color break, streaked growths, decline overall) and enjoy the rest--though I would quarantine them, perhaps on their own bench, and most likely not divide them (or simply divide them to maintain vigor and destroy the divisions). I'd further work to minimize cross contamination by using a completely different set of tools for new plants (ie red handles/red watering can/red etc. stays with suspect plants and green goes with non-suspect...)
Just my $.02

Vicki, viruses, as you know, are passed on through the plant sap. This mean cleaning tools for division, but the main vector is aphids , scale, spider mites, etc. All sap-sucking pests can be potential carriers, which is why virus generally is on the march. Mass production of plants almost guarantees viruses will spread, despite massive insect control. Lots of Phalaenopsis are virused.

This means that disinfecting your green house is quite simple: kill-off all potential carriers after the virused plants are destroyed. A proper fumigation may be all that you need, but I would also go through with a Kärcher (pressure water cleaner) to clean crevices and replace any organic parts of the display, such as bark and wood, which may harbour insect larvae and/or eggs. Benches can be wiped down with a chlorine-type cleaner (chlorox in the USA). It is a bit of work and more than may be required, but I have a destroyed collection behind me, as well. It was painful at the time, but time and orchids simply march on! My current collection is much nicer (in my eyes, of course, but half the fun of orchids is the actual seek and obtain process).

Also, as general precaution, all venting to the greenhouse will profit from insect screening.

Many plants can and do live well with viruses, including orchids. Such plants may be enjoyed in isolation, but will always be a potential typhoid-mary in your midst. If an infected plant is particularly rare, some form of reproduction could be considered (meristeming may be virus free) or a special windowsill reserved for this particular treasure. Although it is generally thought that pollen does not carry virus, there are a few cases that dispute this, therefore I would refrain from using the plant(s) as parent. Simply not worth the trouble.

As we have no current method of cure, we need to consider what we want from our orchids. Those who breed and exhibit have a clearer path than those who simply wish to collect and enjoy. Viruses are prevelent and we need to learn to live with them to some degree. Not any easy call.
Jamie

Vicki, so sorry to hear about your virus problems.

When you disinfect, how do you do this?

With cutting tools, I recommend that metal blades be flame sterilized to glowing red, if possible. If not possible, I use a prolonged soak in straight chlorine bleach. I have heard that a soak in water saturated with trisodium phosphate also works.

Plastic pots are thoroughly cleaned, then get a 24-hour soak in 10 parts water to 1 part bleach.

Clay pots are thoroughly cleaned, bleached, soaked in tap water, dried then put in the oven and temperature slowly raised to 500 F and held at that temperature a half hour, then kept in the oven to cool to room temperature.

Vicki, I'm really sorry to hear this. I know you've been struggling to find out what was happening to your plants.

In addition to the modes of transmission noted above, we cannot forget that water splashing or dripping from one plant to another is probably the easiest.

After removing the plants, clean up any dropped leaves, old flower spikes, and spilled potting media, then thoroughly douse every surface with Physan at 2 tablespoons per gallon. Personally, after that dries, I'd do it again to make sure you get everything. Chlorine bleach at a cup per gallon will also work, but I prefer Physan for safety's sake (at the very least, it won't bleach your clothes!).

I am very sorry to hear about your virus issue. I think you are describing every orchid-grower's worst nightmare. I have not tested my orchids.

I grow many other plants and, with some of these plants, no one really worries about virus, so I have wondered, many times, if I should still grow orchids or give it up. In the end, I decided to grow the orchids, enjoy them, and not worry so much about virus. If an orchid would show any signs of virus, I would get rid of it but, otherwise, I am going to just enjoy them.

I am careful, of course, with the orchids, I take precautions, but, in the end, I know a single scale infestation could decimate the orchid collection. I do try to keep pests eliminated, I try to keep the orchids separate from the other plants and I wash my hands very well in between plants. I use quite a bit of bleach (caution...bleach corrodes steel very quickly). Just to be extra careful, when I take my orchids to an OS meeting, I make certain they are not touching anyone else's orchids even though my orchids have not shown any sign of virus.

Personally, I think, for the sake of our agriculture and food supply, our government should not allow diseased plants to be sold and shipped throughout the U.S. What benefit is there to allowing it? If testing costs just $5 a plant, why not test all the stock that is to be cloned, hybridized or crossed as well as any new introductions that come into a facility that produces plants? The facility would benefit as they would be known for selling plants that are healthier and more vigorous. I think people would be willing to pay $5 more for a plant, too.

Thanks very much to each of you who replied to my thread!
As I said in my post, before I sent samples off for virus testing, I was determined NOT to keep any orchids that tested positive. You changed my mind, though. I see now that my decision was not realistic. I was so sure that I had thought things out sensibly, but I hadn’t or else I would have considered pests/sap...new acquisitions...splashing water etc. I realize now that "unavoidable", as Tindomul said, would be the case. Honestly, I simply wanted a clean greenhouse once more...no more sick orchids that I haven't been able to cure. Of course, diseases and pests are inevitable sometimes, but I was so tired of trying to help my plants but couldn't. As Ray said, I was struggling to find out what was happening.
I worked the entire day today and a big part of yesterday trying to disinfect benches, walls, floor, etc. (my gh needed a good cleaning anyway) I decided to keep the orchids that tested non-virused on one bench and sit about half of the virused ones on the other bench...opposite each other. I then gave away the other half of virused plants to a friend.
Again, thank you so much for your advice. I do appreciate your help and input.
Vicki