That looks like damage from some type of insect rather than disease. You can see where something has eat part of the leaves away, and I suspect that the small spots with brown leaves is where the insect has eaten near the base of those leaves. I would spray the tree with something like "Sevin," and that will probably take care of whatever it is. If it starts looking very much different later on, post some more pictures and we can look at it again.
Fireblight will cause dead and brown leaves too, but you will see the infamous shepherd's crook and not see where something has eaten part of the leaves. However, if you start seeing the limb dying back as time goes on, and the crook appearing, that would change things. Good luck.