Fire Blight on the Apple Tree

We planted two apple trees the summer after we moved here (2006)  One has grown faster than the other.  For the past couple of years, they've had branches that just start to whither and die.  We found out it's called fire blight and the way to get ahead of it is to prune the branches that are dying.  And you must dip the clippers in rubbing alcohol after each cut, so as to not pass on the blight to new areas of the tree.  For the past two summers, I've worked regularly to prune any branches that were showing browning signs.  Just when you'd think you had gotten it all, Bam! more branches kept on dying.  And I'd pray for my tree.  I felt kind of like the master or servant of the vineyard in Jacob 5 asking:  "What more can I do for my tree?" 
This year, we got way more blossoms than ever before...tons of them.  But the fire blight continued and I trimmed and pruned away.

Before a pruning on May 27th, 2013...

 The dying branches I cut off...

 After...

I sometimes felt, we'd have no tree left if I kept cutting away.  But I continued to pray for my tree.  If anyone could help, it's the Lord.  After all, he created the world.  He knows what to do.