All experienced bulb growers had varied encounters with viruses and none happy. In my case I had two major disasters with virus and both involving the plunge beds so much praised in England. That, is clay pots with bulbs plunged in a gritty mix to provide uniform conditions resembling those of the soil. No doubt it works for small greenhouses and alpine houses they have in Britain and the plants in them look incomparably neat and tidy and a t a level where close admiration is possible. A virus like that in the Sparaxis of the wiki appeared in one of the plunge beds and spread to the irids: Babiana, Watsonia, Ixias and of course Sparaxis. the plants' growth was stopped and they looked weak , besides the tell tale streaks in the peapsl. We had to remove the whole bed, burn plants, mix, ppots and sisfect it. In it we grow full sun ferns, in the hope that the possible prersence of the virus anywhere in the bed could not affect somethng so afar from bulbs. Something that contributes a good deal to virus spread is the vegetable garden notion that bulbs will not live without being (heavy) fertilized). High nitrogen or even nitrogen will develop a darker green foliage and this can mask the mosaic symptoms that are faint at the beginiing. Many years ago, an article in Plant Life by a rural commercial bulb grower explained how he had solved that virus problem that was of so much concern to the Dutch growers and others elsewhere. He simply spread heavy quantities of old manure on the bulb beds and the ugly markings never appeared again.