Q.My roses have black spot
My roses have black spot. What is it? How do I get rid of it?
Black spot is a fungus that attacks many rosebushes. Once it has left its mark on the foliage, it will not go away until new foliage comes forth. The best fungicide I have found to kill it once it has gotten its hold on things is called Mancozeb. I get it from http://www.rosemania.com . Tell them Roseman Stan sent you. Here is an article about it for you too: https://www.gardeningknowhow.com/ornamental/flowers/roses/black-spot-roses.htm
I keep my rosebushes sprayed with a fungicide called Green Cure from the first leaves opening up in spring to the end of the season. I spray them every three to four weeks with it. Depending on weather conditions of course. If it is higher in humidity or dampness out, I spray every 7 days.