On 7 Apr 2014, at 8:59, Jerald Lehmann wrote: > I'm trying to figure out what is so bad about growing virused plants. The issue (or so it seems to me) isn't that virus X slightly weakens plant Y; it's that the same virus will kill plant Z. A further point: any plant propagated vegetatively will gradually become infected by more and more viruses. Each virus does little, but in aggregate they weaken a plant making it progressively less easy to grow and propagate. The cleaner the growing conditions, the more slowly this process takes place. This is probably the reason that many (most?) old cultivars of various garden plants are out of cultivation. Or take Cosmos atrosanguineus for example: forty years ago Graham Stuart Thomas considered it miffy and difficult, and it was effectively unobtainable. Then someone must have run it through tissue culture and gotten rid of the accumulated viruses, and these days it's widely available and easily grown. To put this in other words: you may think virus infections are innocuous, but they aren't. -- Rodger Whitlock Victoria, British Columbia, Canada Z. 7-8, cool Mediterranean climate