Ursula what made me suspicious about my L. candidum was that the foliage was malformed. Yours should be healthy from the start as you raised them from seed. If you do get virus on them it will be because they are very susceptible to virus and this will also be an indication that you have virus on other plants or lilies, although they perhaps don't show symptoms. This was very different to the situation I had getting a virused bulb. So your L. candidum are not dangerous to your other lilies, rather other lilies are dangerous to them!
