We just moved into a home with lots of land for gardening, and several established plants. One bush (sorry, I don't know what it was) was covered in black spot fungus. . . EVERY leaf. It was clear upon further inspection that many of the fallen leaves were so old they've decomposed into the soil. I would like to take the bush completely out and use the land for strawberries. Do I need to treat the soil first so it won't infect my berries (and how should I do that) or should it be okay now if I watch the berries and take preventative action?