North American Fruit Explorers mailing list at ibiblio

["Kieran &/or Donna" <holycow@frontiernet.net>]

Doug wrote:  "Reputedly apples left on trees after leaf fall will cause a 
decrease in  the tree's cold-hardiness if it is at all marginal. "

Wow, I never thought about it, but I'll bet it would.  It's certainly true 
that citrus varieties that ripen fruit in the winter are not as cold hardy 
as those that get done early so they can go dormant.  If you live in a 
climate where you need your apple trees to shut down completely to deal with 
very cold winters, I would not leave fruit on the trees after the leaves 
fall.  Donna