Lots of things have been said here. Unfortunately, Camille's is the most head in the sand. I wouldn't have expected that actually.
To hang your hat on the fact that plant viruses don't spread through the air is pollyana at best. There are several completely ridiculous "ifs" in her statement. For example if your collection is insect free...exactly how does one guarantee that? There are many other ifs she ignored...like if you sanitize your hands between touching each plant, if you never have water splash or drip on an adjacent plant when watering, or never have foliage rub on adjacent plants in the breeze. Unfortunately her position is similar to someone saying you can prevent fires by eliminating ignition sources. You can minimize them but they are infinite and uncontrollable..like lightning, or unanticipated arcs in switches, or static discharges from clothes of different materials rubbing together. You can only totally prevent fire by having no flammable materials or mixtures. You can only prevent virus by not having any in your collection..anything less is minimization, not prevention.
Rowangreen suggests some orchid viruses might come from wild collections. There is an excellent article in the current edition of Phalaenopsis magazine, the Journal of IPA. It is by Erin Wood, graduate Research Assisstant and JE Polston Professor, Dept of Plant Pathology, University of Florida,Gainesville, FL. Every one of you should find a way to get a copy. It's simple, down to earth, and in complete disagreement with most of the statements made here on this thread.
In speaking of ONLY CymMV and ORSV (the two most prevalent in orchids) they say, "CymMV and ORSV are unique in that they enjoy worldwide distribution and have only been found in propagated orchids---never found in wild orchids."
If you only have 6 orchids who the he** cares. You can throw them out and buy 6 more. If you have 2500 orchids like I do with a few really valuable ones, you must test and dispose/isolate infected plants. Anything less is fooling yourself.
As to which orchids get viruses...all of them though in my experience some genera seem more susceptible.
The article above also addresses the issue brought up by someone about asymptomatic plants. The explanation has nothing to do with the plant genetics and everything to do with strain of the virus and the stress endured by the plant.
This a complex subject. I sure am not an expert. Science in general is still learning about these things. That said, some of the stuff I see here is nothing more gut feel science with no effort to get informed.
Thank you.
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