Where did you get that cockamamy idea that dwarf trees contain viruses
that result in their short life times? There are dwarfing rootstocks that are
sold as virus free selections. The reduced lifetime is probably due to the
smaller root system of these dwarf trees.

It makes sense that there is a virus - it's why they don't grow tall
and why they fruit early. Glad you asked about the source of the
info... Jim McCausland NW bureau chief of Sunset Magazine, he told me
about the virus while standing next to my semi-dwarf apple trees.

Richard Reames
http://www.arborsmith.com