Epidemiology
Claviceps purpurea has been known to mankind for a long time, and its appearance has been linked to extremely cold winters that were followed by rainy springs.
The sclerotial stage of C. purpurea conspicuous on the heads of ryes and other such grains is known as ergot. Sclerotia germinate in spring after a period of low temperature. A temperature of 0-5°C for at least 25 days is required. Water before the cold period is also necessary. Favorable temperatures for stroma production are in the range of 10-25°C. Favorable temperatures for mycelial growth are in the range of 20-30°C with an optimum at 25°C.
Sunlight has a chromogenic effect on the mycelium with intense coloration.
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