This year my neighbors and I have all experienced Echinacea flowers about to open, and before that happens, the stem breaks about 1.5 inches from the bloom and the flowers die. Some plants do not develop any ray flowers, only disc. There is no evidence of disease on the leaves though. We are all experienced gardeners [my PhD in Agronomy from U of I, 1984]. We have never seen such damage. I saw one photo on your web site depicting this damage, attributed to Alternaria, but I see no related damage on the leaves. There is no evidence of powdery mildew. It has been a particularly rainy, hot, humid summer. They sprayed aerially 6 wks ago for gypsy moth with Bt and Gyptyk, don't know if that may have caused this.