Within 5 days the florets produce a sticky ooze containing more spores which can be spread by insects, and rain splash to other florets. Eventually this ooze is replaced by the black ergot body where the seed would normally be. Wet, cool and cloudy weather can cause flowers to remain open longer and be more susceptible to infection. Poor fertility and or herbicide injury often keeps flowers open longer. Non-uniform cereal crops provide more hosts for the continuation of the oozing stage causing more spores to be released.
Copper deficiency can also cause flowers to remain opener longer letting more spores enter.
Penny Pearse, plant disease specialist with Sask. Besides the wet weather favoring the fungus it also favored the increase of small insect populations to spread these sticky spores. Weather played a much greater role in the ergot outbreak this year than all of the reduced tillage we have been practising. It has been many years since we have had such a major infestation. The risk of all these weather factors lining up so closely again next year is low.