Quote:
Originally Posted by Roberta
Not airborne. Water, maybe since it gets absormeb by roots and may also contact breaks in either roots or leaves. Actually, the #1 vector is humans. Sucking insects would reasonably be expected to transmit viruses, to what extent I don't know if it has been well measured. I know it isn't completely straightforward. One of the members of one of my societies actually experimented with a batch of seedlings (so a bunch of identical plants), and tried to infect some of them on purpose to test what might produce transmission. Over a period of several years, they still tested negative. On the other hand, legacy collections tend to have high rates of infection even though the owners really tried to follow good hygiene practices. So does age have anything to do with it? Or what other factors? I don't know what studies have been done. This same individual who did the test on the seedlings put together a "visual" test of multiple photos, showed it to a number of very experienced and knowledgeable people (judges, people with a botanical background, etc) to see if they could tell the virused ones from the clean ones. Nobody did better than chance, some did worse. Conclusion, appearance is an unreliable indicator.
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There's a good article about appearance, I think by Sue Bottom, can't remember if it was on AOS, Orchid Digest, or the St Augustine's Society website. They all get mixed up in my mind by now Lol.
But the story goes something like she walked through the green house with the guy from Waldorf Orchids and all the plants that "looked" virused tested negative, and the ones he suggested to test were positive. It was kind of a tribute to his keen eye, but also made the point that appearance wasn't, as you said, a reliable indicator. At least for the rest of us.
Did the person you mention publish his work at all?
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