These are symptoms of the disease aster yellows. The photos are Aster Yellows on my coneflowers, which I will not keep, but destroy as per the information below. Aster yellows is caused by a tiny ...

In addition to a range of abiotic disorders (typical to most ornamentals) and diseases, including the much-despised aster yellows, botrytis, and powdery mildew, they suffer at the mandibles of a ...