Hello fellow geeks!

[OhLaLa Orchids]

I'm online tonight searching for details on viruses that afflict orchids and I stumbled upon your community. Looks like you all have lots of valuable info. My wife and I caught orchid fever after one of our six rescued orchids finally bloomed (Milt. Echo Bay 'Midnight Tears') which led to buying more Miltoniopsis and then a Cattleya bloomed and we got more of those and then a Cymbidium and then... well you get the picture. It's now 7 (8? 9?) years later and we've moved from the window sill, to the basement, to the barn, and now to our new land with an 800sq ft greenhouse filled with over 1000 orchids. Sorry to say that Echo Bay is long deceased and we've got a basket full of name tags of other plant gone to the compost pile. But we've loved the learning and I can't imagine life without the beauty of orchids all around. Ok, nice to be a part of this forum, now back to looking for more pictures of viruses (ick!).

[pikevi]

Welcome to the forum OhLaLa Orchid

It is nice to have 1000 orchids,indeed.

[mayres]

Welcome! I'm still resigned to the (pseudo-basement) spare bedroom and only DREAMING of a greenhouse. Look forward to hearing what you've learned over the years and seeing some pics of your fav's. mike

[Cynthia, Prescott, AZ]

Well, the basement won't get overheated if you forget to switch the plug from heater to cooler during a wiring problem. Lost a few orchids to excess heat, including my C. luteola, and a ton of black leaves, with some plants yet to finish the belly up process.

OK, try looking at my pbase site: http://www.pbase.com/schnitz/virus_in_orchids
I have a particular interest in cleaning out my currently 800 plant collection of virused plants. Made pretty good progress so far, hence the pictures. Leaf or flower symptoms are not enough for viral ID. Most of the positive plants showed no symptoms. They were chosen for testing because of other factors. The only pretty sure fire visual indicator is color break in flowers. If you use Critter Creek for testing, don't waste your money on the GH screening. It has as higher probability for false results than the double well test. I have had such results that were straightened out with the better test. I am currently embarking on a project to do my own virus testing, using a quality compound microscope at 1000X to look for viral inclusion bodies. There is a how to article in the Oct '86 AOS Bulletin (now called 'Orchids'). It is not simple or fast, but fits my style (I hope). I currently have about 50 virused plants for use in developing my scope technique. Should be a couple of months or so before I start the actual search for viral bodies under the scope. The good part of this testing is that I am not limited to the 2 major viruses that infect orchids. I should be able to find other viruses, tho I may not know the exact variety. However, I will probably be able to identify the family of viruses it is in.

I apologize to those that were hoping I would chime in on there post, but this microscope stuff has be taking an inordinate amount of time.

[pikevi]

Cynthia, Thank you for the URL.

Very informative. I am yet to face any crisis of any infection in my orchids. I hope I never have to.

Just curious:

a). What size are the CMV and ORSV viruses?

b). Can they be identified by an optical microscope even at 1000X?

c). Can the infected plants be treated ?

d). If they can be what drugs, if any , are used?

Thank you.

[Cynthia, Prescott, AZ]

The virus itself is too small to be seen with a regular microscope, it requires an electron microscope, which is not practical for any but universities. The viral bodies are characteristic objects formed by the viruses and require the 1000X and special staining to see. There is no known cure for virus. There is some belief that the cloning process can remove the virus, but that the usual cloning labs don't do a good enough job of separating the promordial germ from the virused cells to succeed in removing the virus from the cloned plants. Any reasonable sized collection will have virused plants, period. I am sure you have some. I have gotten numerous virused plants from reputable orchid nurseries. They generally have no way to test there stock, so thay really can't guarentee that the palnts are free of virus. They and you just have to trust to good technique to avoid spreading the problem. I started testing because I knew I had a problem from something stupid I did 20+ years ago, and the plants from that era were showing severe symptoms. Symptoms generally get worse with time. Note that a few plants that sat side by side the virused plants all those years came out negative and are still in my collection.

[pikevi]

Thank you Cynthia,

Great explanation.

I will concentrate on keeping the basic requirements for the orchids within the ranges and hope they all will be healthy.

And just out of curiosity again; do plant cells allow more than one type of virus to infect them? ( Just in case you are wondering about the question, I was thinking of 'interferon' theory in humans).

Thank you.

[Cynthia, Prescott, AZ]

Don't know anything about interferon, but yes, more than one virus can infect a single plant. About 5 or 10% of my virused plants were doubly virused, they had both of the viruses tested for. I don't think we went over proper technique, tho you probably already know, but for those reading this, all tools used to cut plants must be treated to sterilize (actually, denature would be more acurate). A soak in 10% fresh bleach solution, a soak in saturated TSP (I keep my tools stored in this), or heating the tools to a lot hotter than you would want to touch. Also, one should be concerned with handling roots will repotting, as there are plenty of open wounds at this time, and hands can transfer virus to these wounds. Disposable gloves are best, or, as I do, use sterile prunners to remove the old bark, and never handle the roots. Use new or sterilized pots, bleach for plastic, or oven for clay (~2hrs at 400F). Never reuse mix.

[pikevi]

Thank you Cynthia.

That was very informative. All are very valid recommendations for a healthy set of plants.

I am guilty of re-using the mix, simply because I picked up a habbit of re-potting all the plants I bring home. It is the first thing I do.

With Orchids I do the same but I remove them with care. I am sure some of the roots undoubtedly would be damaged. That is the only reason I have to re-use the mix. I will remeber your advice when te time comes for re-potting for other reasons.

[Cynthia, Prescott, AZ]

Reusing the mix on the same plant that it came from, if it is still good, is OK. Just don't share mix.

[pikevi]

Thanks Cynthia,

I will remember that.