What Causes Sunflower Mold or Blight on the Flowers Themselves

Question

My Mammoth variety grew 8 to 12 ft tall and all produced beautiful, large flower heads. Then all but one died within a very short time of each other. It appears that they were the victim of some sort of mold or blight. Too much water, wrong fertilizer? Incidentally, most of the plants continued to have healthy leaves. Please, help me.

Answer 1

It is possible that it was Sclerotinia Head Rot. This can happen if the head of the sunflower is slightly damaged - say by winds, heavy rain or hail, which gives the fungus a route in. The fungus will not attack uninjured leaves and flowers, which is why the leaves are fine.

Here is more info:
https://www.ag.ndsu.edu/pubs/plantsci/rowcrops/pp1193w.htm