Thanks all for the comments.
I haven't used the 'Corsica' imposter in breeding. It and the 'Sancerre' imposter are from the same supplier and in the same pot. The 'Sancerre' imposter had one stem fail and die back (producing the stem bulblets), whilst the last 'Corsica' imposter bloom has shown this blotching.
I have used some of the 'Sancerre' imposter pollen on one other lily. If the 'Corsica' imposter is virused, then to me there is a good chance the 'Sancerre' imposter is as well (and it is white, so would be much harder to tell). Hence my concern.
