North American Fruit Explorers mailing list at ibiblio

[Terry Bradshaw <terryb@lostmeadowvt.com>]

These charts should always be read with a grain of slat.  There is a big 
difference between disease resistance (don't get it as bad as others) and 
what has been called field immunity (Scab: Liberty, Freedom, Crimson Crisp, 
etc.).  Yes, I know that Vf resistance can be broken down, but for all 
intents and purposes most of the PRI and NY SRC (scab resistant cultivar) 
releases can avoid scab sprays.  The resistances listed in the table are a 
varying scale of how bad the variety gets scab (in particular, and my disease 
of focus here).  Honeycrisp gets leaf scab, but I've never seen fruit scab 
although we do spray ours, even if some get organic controls.  It gets black 
rot something wicked, though.  In my experience Paulared requires a full 
fungicide program for scab, and extra attention to powdery mildew and fire 
blight. Zestar! gets scab for us as bad as McIntosh.
Local conditions may play a role, but I would hesitate to plant an orchard, 
expecting not to spray any fungicides, based on this table.

My $0.02

TB




This is an interesting tabulation of resistance and susceptibility
to several diseases for a number of mostly older apples grown by
householders in Minnesota.

I was interested to see a reminder of why Wolf River is a pretty good
utility apple for zone 4 even if it's a bit on the bland side in
flavor. In my limited experience the texture is quite nice when
grown here in the Niagara Peninsula in Agriculture Canada zone 7a,
near the northern limit of commercial peach growing.

See
<http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/p244apple-diseaseresistant.html>

Doug Woodard
St. Catharines, Ontario, Canada


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Terence Bradshaw
Calais, VT 1450 feet, zone 4

http://www.lostmeadowvt.com