On 29 Jul 2011, at 9:42, Mark BROWN wrote: > ...snowdrop collections or any collection for that matter are a > minefield for virus and very little can be done about it. Tissue culture is the key. That's why Cosmos atrosanguinea is a very common plant in nurseries today, whereas 30-40 years ago is was something you only read about in the very snootiest books and had no hope of ever seeing, much less growing. It was not only rare, but weak and tricky to keep going because of a high viral load. Someone, somewhere, put it through tissue culture, cleared out the viruses, and now it's growing happily in gardens everywhere. [For some definitions of "everywhere".] Tissue culture can be done in the home, believe it or not. Some orchid fanciers, I understand, carry out their work in the bathroom, first running the shower with hot water to fill the room with steam, then waiting until the steam and all the dust it has dampened settle to the floor. And one enthusiast here actually had a spare bedroom set up as a tissue culture lab, complete with laminar flow cabinet. Yes, it undoubtedly cost $$$$, but not so much as we may think. She's since found the light of her life, married the lucky man, and is happily raising rabbits, sheep, llamas, and bees in the Cowichan Valley. What happened to her laminar flow hood I don't know. You would expect the Dutch bulb industry to be in the forefront of cleaning up viruses from their stock in trade, but it appears that they are so interested in making money that they don't care. When you buy Crocus kotschyanus from Dutch sources, you get a form that has small, badly distorted flowers, whereas a clean stock has flowers as big as good forms of C. chrysanthus. And then there's Narcissus 'Tete a Tete', widely grown in pots to be sold in flower in early spring, but always with the tell-tale signs of viral infection. -- Rodger Whitlock Victoria, British Columbia, Canada