I’ve been doing a lot of reading recently on GardenWeb’s forum and there seems to be a lot of Fire Blight posts out there. Im beginning to wonder if all of the damage from the frosts and freezes has given an entry way for bacteria pathogens to invade tender growth.
I recently came across an article online about Fire Blight resistant strains found in NY late last year: Resistant Strain Detected in NY
Fire Blight is the most devastating disease an apple tree can get.
Prevention is key, and cutting off and burning infected shoots is needed to prevent the disease from getting into the trunk and then the rootstock killing the tree.
There is some fire blight forecasting software out there as well.
Give the above link a look.
Below is a gallery showing what fire blight looks like and the cycle of infection.