Cosey (catching up on months of activity, but your comment is recent) I am also struggling with DMV detection and elimination. I have two plants that tested negative for DMV this spring at two labs, yet those plants now show symptoms. These plants have been grown exclusively in my basement since early June and have not had any aphid exposure.
Meanwhile sister cuttings (same parent tuber) of one of these plants were grown in my field, were surrounded by DMV- plants, were asymptomatic, and yet tested DMV+ at Agdia this fall.
Was DMV present in the mother tuber from the onset but the tests miss it this spring? Could activation of DMV-EPRV be possible? Itās bewildering.