I am considering starting to spray my more susceptible roses now, Eileen, despite the fact that there is no sign of any infection yet. One of mine - Schoolgirl, is a martyr to it every year, and I always promise myself that I shall start earlier, but forget. Don't do it if there is a forecast of very low temperatures, but the next spell of warm and dry I don't think would be too early. I'm sure you know which ones of yours are affected worst, and you could start with those.