Is this fire blight?
Thank you for your diseased tree question; I am sorry no one has responded to you. Although these leaves certainly resemble those with fire blight, there are a myriad of pathogens and insects that can cause a fruit tree to have dead leaves. Fire blight is caused by a bacterium; verticillium wilt and phytopthora are conditions caused by other biotic pathogens.
It is nearly impossible to diagnose exactly what condition(s) your trees are experiencing without a photograph of the entire tree (to see if it exists throughout the structure, or whether only sections of the trees are impacted) and a closer look at the trunk and stems.
Here is a link to your state's extension material to fruits that show resistance to some or all of these pathogens, if your trees have or will need to be taken out and replaced.