I am living in Northern Alabama working at a place where my main project is to plan a permaculture designed fruit orchard. I've been buying trees, still in their pots, and not planting them but putting them next to older trees in a raised bed. In the past few days, many of the pear and peach tree leaves have turned a greyish black. The branches are still alive but I don't know what it means! It's too early for them to being going dormant. The only thing I can think of is them not getting enough water for a few days. I looked up photos of fire blight but that's not what it looks like.
Overall and detail pictures are good. Often state universities have an Ag extension service that is good for disease questions. We have a number of state publications that target local disease patterns.