Much of what you state has proven to be reasonably accurate although canna virus will not transmit by simply touching. Virus infections are primarily transmitted via a vector capable of injecting the virus into the viable host plant.

Anyone growing purchased canna plants/rhizomes should certainly grow the new cannas well removed from their clean stock and they should prevent vectors transferring disease by using effective systemic insecticides.

I would recommend discarding any diseased plants and be aware of the fact that even virus indexed cultivars or seed grown plants are only safe if grown in a clean and vector controlled environment.

Kent

Thanks Kent for your comments ... although I'm tempted to keep the young new plants in which are already showing signs of disease, I know it's for the best that I properly dispose of them asap!