I found that horticultural sulfur works even better if you do not mind the smell.  The smell of sulfur dissipates once the solution dries.  You mix it in water with a few drops of dish soap (follow the amount per gallon on the package).  After spraying the foliage it is wise to spray the soil around each plant since this is where the spores settle just waiting for rain to splash them back up onto the foliage.  Remember to remove all infected leaves and put them out with the trash (and not into the compost pile)  Spores can remain viable in the soil for a very long time so you need to break the cycle.   Mulching around your roses yearly will help break this cycle. Each year just add another layer on top of the mulch you place the previous year.

Ron ~ zone 6b ~ Ontario

thanks so much for the info.what would i do without you rose woman..lol velvet

I use 2 t of baking soda, a couple of drops of dishwashing detergent and 1 gallon of water.  Put in a spray bottle and spray it.  ( you can half the recipe)