Garden Pests and Diseases: Brown spots on leaves of amelanchier trees, 1 by glenpark

glenpark wrote:
Dear readers, if someone could possibly identify the disease afflicting the leaves of our amelanchiers (serviceberries) (see photo), that would be so very much appreciated. While they still look ok, and the trees are producing their summer berries no problem, the same spots happened last year, and seemed to accelerate their defoliation such that by August they were almost if not quite bare. They\'ve been in the ground since May 2017 only. Vermont, zone 4. I\'ve done a lot of reading but cannot decide which of the various options it is, and thus am unsure whether and how to treat. (Perhaps I should note that they\'re downwind from two pear trees that were similarly afflicted last summer.) Many, many thanks for any and all suggestions. Glen