I use oil to control mites and scale. If scale is the primary problem 2% at half-inch green is good, for mites 1% at tight cluster. I always use some kind of summer oil and combine with Nova. The Captan label says nothing about waiting 2 weeks after an oil application- just that there should be a little seperation. However I have sometimes experienced some phytotoxisisty with a captan application at around that interval, but only on a couple of varieties. Tomkins King in particular.
Where I have susceptible varieties, and pears are also susceptible to this kind of injury now that I think of it, I remove the Captan from the pedal-fall application. I use a combination of Imidan, Flint and Nova in this case where I'd normally use Nova and Captan with the Imidan. In the scores of orchards I manage I get almost absolute control of scab and CAR and very good control of Plum Curculio with a 3-spray program. The Imidan sprays are at pedal-fall and 10 to 14 days later.