Could be either or- scab is a gypsy fungus and gets around long distances during periods of rain. That's why cultural controls like removing leaves at end of season only get you so far.

Immunox has good kick-back if the disease looks like it might really slow your tree down but by now it may be warming up enough that scab has bout completed its cycle.

If they were breaking dormancy when you bought them, they probably didnt have leaves exposed, so the apple scab most likely came from a source at your home.

I wouldnt worry about it too much, leave them as is, and clean up ALL leaves in the fall. I did the same in the fall last year, and I have no scab so far this year.

-Eric
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If leaf removal was all that affective I suspect commercial growers would consistently blow leaves into a pile and burn or wash quick lime over them.

I did say "so far"... :)
I picked up every single leaf off the ground and put down compost over the top of the ground.
Overwintering of the dropped infected leaf is the cause of spring/summer infection, remove the leaf, remove a majority of the problem.

-Eric
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Recently I saw a Sustainable Ag research project where super-cleanliness was successful with apple scab.

All three of our apples are resistant. The VA extension service says resistant varieties are the only hope in the humid mid-Atlantic.

Planatus, I am surprised to hear that. I have almost no scab in the mid-atlantic and always considered it a more northern disease, our hot summers bake it out. Maybe you are more in the mountains, I see you are in a colder zone than I am. I never spray for it and only one year have I had any scab to speak of.

Re: the original question, I don't see any reason why it could not be on the bark and in the buds. New trees are very susceptible since they are weaker, so only a small amount of scab could go a long ways. Most of the scab overwinters on the leaves since thats where it mostly was, but it could easily shed onto bark etc. Your scab also could have blown in, the original source could have been miles away.

Scott

So, barring death of the tree(s), would extreme cleanliness at the end of the year perhaps ameliorate this? I guess this is a good introduction to the apple diseases in my area... I wish there was a way to sample some of the various other apples that are offered as being more suitable for here. It's hard to say "I want to grow a Liberty or William's Pride" when I don't know what they taste like. A small aside, growing up in Upstate NY we used to find old remnants of orchards everywhere and it was great fun sampling all of the different apples. Sweet ones, tart ones, bitter ones, insipid ones... Some would be so amazing.

I haven't seen the research mentioned above but I would guess that if leaf removal was to be successful you'd need to be in a location where there weren't untended diseased apples nearby. I'd like to see that research to see how far the researched trees were from outside contamination- that would mean everything. However for a homeowner I don't see any reason not to go ahead and be as sanitary as possible.