Cherry tree spray
When and with what should I spray my Rainier and Bing cherry trees?
Washington County Oregon cherry trees
It depends on what pest or disease you are trying to control. I recommend the cherry pest management guide to familiarize yourself with the different pests and diseases and the timings.
If you are a backyard grower, there are specific recommendations for non-commercial use in the PNW Insect and Disease Management Handbooks.