I have a native Dogwood tree that is suffering from Dogwood anthracnose. It is situated all by itself in a mulched bed that gets full sun all day. The leaves and flowers developed brown spots and blotches and eventually shrivelled up. I pruned off all affected parts and now the tree is beginning to replace all the lost foliage with fresh shoots. What is the most environmentally friendly treatment for this disease? I've heard that certain treatments harm not only the pathogen but nontarget organisms as well, and I'd rather refrain from using highly toxic sprays.