There are several things that could be going on with your tree. If you can send pictures I can try to identify the problem. If I cannot tell from the pictures or if you cannot send pictures you will need to bring samples into the office. We are located on the Deschutes County fairgrounds just off of parking lot D.

Here are three leaves from different parts of the tree. We cannot see any insects Thanks

Since you see no insects I have to say this is most likely Coryneum blight. I have attached management information from the PNW Plant Disease Management Handbook and a short publication with information about the disease. I cannot definitively say this is the problem, but based on my research, it is most probable. To get absolute diagnosis I could send a sample in to the campus plant pathology lab where they have the ability to raise this disease and equipment to identify it exactly. There is a charge  of about $60 for this service at campus and I would need several 6-12" branch specimens to send in.

http://pnwhandbooks.org/plantdisease/cherry-flowering-prunus-spp-shothole-coryneum-blight

http://pnwhandbooks.org/plantdisease/peach-prunus-persica-shothole-coryneum-blight

http://www.ext.colostate.edu/ptlk/1444.html