Viruses

[nhbeek]

It's certainly not ecenomical for a retailer to test every plant.

It has become more common for high end sellers to test each plant and guarantee it arriving free of virus. There are several sellers on ebay who do this, and that was probably the context from which op's question arose. For them it makes ecenomic sense as their plants often sell for 200-1000$.

One's opinion of this practice is likely based on ones's opinion on the merits of maintaining a virus free (or as close as possible) collection. I value this because my plants are expensive and grown under lights, which results in them being in close physical proximity. If I had thousands of cheap cattleyas in shade houses I wouldn't care.

[Roberta]

They can guarantee that it is free of the most common viruses, for which readily-available tests exist (especially reasonable for expensive plants), but how can they guarantee that it is free of ALL viruses?

[nhbeek]

Originally Posted by Roberta

They can guarantee that it is free of the most common viruses, for which readily-available tests exist (especially reasonable for expensive plants), but how can they guarantee that it is free of ALL viruses?

They don't. Here is an example of what one such seller promises:
"This listed plant has tested negative for CymMV and ORSV."

[Roberta]

Originally Posted by nhbeek

They don't. Here is an example of what one such seller promises:
"This listed plant has tested negative for CymMV and ORSV."

That is reasonable. I think it's especially important on "classic" plants, like if you are getting divisions... so many of those old and wonderful hybrids are virused. I sometimes wonder if plants are like people, becoming more susceptible as they age. I know of several instances of legacy collections, where the owner was very careful with hygiene, that turned out to still have a high incidence of virus when tested (when clubs inherited them)

[estación seca]

Most viruses can be spread by insects.