With Black spot, you have to get rid of the infected leaves and buds. I hand pick mine off. You have to be sure to pick up all the fallen debris under the bush. Black spot will contu to spread even after you have treated it, if you do not get rid of the infected debris or leaves.Black spot will spread through the grass and weeds. Another reason to clean up infected debris. See my blog, troubleshooting roses http://www.gardenstew.com/blog/c283-5-roses.html . It shows you what black spot looks like (from my own garden) and what to do to get rid of it.