Lily disease

I have been having troubles with some of my pot-grown lilies and don't seem to be able to find any direct visual reference to a similar condition so thought I'd post some (rather sad) pics. The lily leaves begin to turn brown from the bottom of the plant, spreading up the stem as the flower buds become deformed and finally fail. It seems that they are rotting so I guess it must be some sort of rot or fusarium problem - maybe caused by watering in the wrong way! It seems lily culture is more complicated than I had anticipated. Anyway, it seems there is no cure, so I shall have to do some digging-up and disposing of infected plants and hope for the best with those remaining....