Garden Pests and Diseases: Coneflower leaf problems, 0 by delphinium01

delphinium01 wrote:
The leaves on some of my coneflowers get leathery, dry, and feel a little \"gritty.\" They eventually dry up and fall off. It doesn\'t look like powdery mildew, and I don\'t see any insects. Sometimes pulling off the affected leaves helps the plant recover, but often the plant dies. It doesn\'t affect all of my coneflowers, just some. I regularly use Neem as a fungicide. Does anybody know what this is or what to do about it?