Thank you for your question, Ken.  Here is the PNW diagnostic manual information on the disease.  Note that none of the recommended fungicides are available to homeowners.  We are, however, reluctant to advise on treatment without first accurately identifying the cause.  You can either attach clear, close-up photos (to this question), or take samples into the Clackamas County Extension office, 200 Warner-Milne Road, Oregon City.  Their office hours are found here:. https://extension.oregonstate.edu/clackamas

Good luck!