I have a spot in my flower garden that suffers from some kind of fungal
disease, perhaps powdery mildew. In late winter I cut back my scabiosa
and coreopsis to the ground, and they start off the season fine. But
by mid-summer they start showing signs of disease. The problem is
exacerbated by the fact that this small area of the garden is watered
by the lawn sprinkler instead of dripline irrigation like the rest of
the garden. Is there any way to eliminate fungal disease from an area,
or at least give the plants grown here a fighting chance?

-Fleemo