Suncrisp was described in GoodFruit Grower last fall as something of a
fireblight indicator -- if there is any fireblight in the area, Suncrisp will
find it. I finally got fed up with trying to control the fireblight on my
several Suncrisp trees, and Suncrisp wasn't an important variety for me, so
this year I've cut down the last of them. I'll let the rootstock put up
suckers to topwork in another year, hoping the fireblight didn't get down
that far into the root system.
I've taken out my share of main scaffolds, which, in my orchard of oblique
cordons, can be most of the tree. Only occasionally has the rootstock become
involved.
Streptomycin spray is used while the tree is in full bloom and is available
at any good garden center.