Dead branches on growing pear tree
This summer a number of individual branches have died. Fully developed leaves turn dark brown/black on an otherwise healtly-looking free having small pears.
Indiana County Pennsylvania
To get a positive identification of the problem, you can take some samples in a sealed plastic bag to your local Extension Office which will forward to Penn State for analysis, From your description, the problem may be:
FABRAEA LEAF SPOT
This pear tree disease is also known as leaf blight and black spot. It is caused by the fungus Fabraea maculata, which appears late in the growing season. This fungus attacks all parts of the tree, which includes the leaves, fruits, and/or twigs.
The symptoms of this pear tree disease start out as brown or black spots on leaves. As the infection progresses, the leaves turn yellow and drop off prematurely. If the leaf drop is severe or occurs for several seasons, the pear tree will be less vigorous, produce fewer pears and could eventually die.
This fungus can also set up house in fruit and will appear as lesions and as the fruit expands these lesions will turn into sunken places in the fruit.
Once this fungus appears in the orchard, it is hard to control. One reason is the fact that it will easily overwinter in fallen leaves and fruit. The other reason is the fact that it can be spread by wind and/or rain. While there are chemical treatments for this fungus, the best approach is to reduce the affect and/or prevent it all together. Keeping fallen leaves and fruit picked up and disposed of if diseased is one simple approach that will reduce the chances and possibly the stronghold of this fungus