I'm a little surprised, but not a lot. This heat and the wet weather before, has caused some wacky problems. Try spraying with manzate only 3 times, at 3 day intervals. That should halt the active infection. Then go back to the regular spray program. The spots won't disappear, just remove those leaves once they turn yellow. Good luck.

If you have blackspot there is only one fungicide which will kill it after spraying it 2 to 3 times every 5 to 6 days.

I have tried many different fungicides and "Daconil 2787" is the one I use now. It's made by ORTHO and has a new name now : "ORTHO GARDEN DISEASE CONTROL" I just got a new 1 pint bottle at Home Depot for about 15 dollars.

Also, I have over 300 roses and only spray those right away which show a little blackspot and a few next to it. I use this for about 15 years and "IT'S THE BEST"