Monday, June 20, 2011
A Weird One
Diseases can be strange. They don't always follow the pretty pictures in textbooks. This picture was taken a week ago at heading time. Brian noticed these heads from the cab of his sprayer when he was applying Prosaro for headblight control. He saw it in more than one or two fields. The number of heads affected in the field will not have a yield impact, there isn't enough of them, but the partially bleached heads stick out like a sore thumb against the green backdrop.
A head like this one matches the classic textbook picture of fusarium head blight in wheat. Fusarium causes partially blank sections of heads that turn white. Except, it is way too early for head blight to express itself. So, what is it?
A survey of qualified experts left some heads scratching. Obviously a physiological response to the environment within the field. That is a bit like a doctor telling you the symptoms you have are an idiopathic response. In plain language that means the doctor does not know what is causing the symptoms.
Some believe it is form of take-all disease. This is the most plausible explanation because of timing. Take-all prevents the head from flowering so you are left with a blank white head. Except as the name take-all implies, this disease "takes all" and does not leave part of the head healthy.
I suspect the real culprit will remain unknown.