There are several bulbs infected in the trade with viruses, and also in native habitat. Some viruses don't show any symptom, but they are there. The big problem ocures, when a virus finds a new host. Because viruses have to adopt to their hosts usually this new host dies very quickly by the infection. This means for example when an important crop becomes infected and dies in mass then there is a huge problem. That is when people start to worry and quarantine or burn plants to stop the spread. For flowerbulbs, as most of them propagated by vegetative means viruses can spread easily. Moreover these are perennial crops, so if it becomes infected you can't cure them with chemicals. It also takes many years, often 15-20, before a grower have enough stock of a new variety to sell it in the trade . So if you decide to keep virus infected plants it is your choice. You can have a nice garden with possibly infected plants, or you can decide to grow only free material, and do the rigorous selection every couple of days and kill the infected plants. Janos Hungary, Z5a