Lori, this is a  tough one. I suspect it is a fungus called cercospra. It flourishes in hot damp weather with poor air circulation. My recommendation is to thin out branches, especially the lower ones and dispose of the leaves. Sanitize your pruners between cuts with alcohol . In bad cases you can apply cooper every 10 days. You can buy in a premixed formula. Try not to water the branches. If you have had a lot of rain and with high humidity this fungus flourishes. I am going on the pictures. I have never had this condition but i try to plant with ample space. My wife would call me a liar. Anyhow let us see if you have good results. Pick up all the leaves that have fallen and i would take off the infected leaves and dispose in the trash. No composting. Also prune off dead branches. Hopefully you have good results.