Protecting wheat from leaf and head diseases
Wheat heads will soon begin to appear, marking the time for some critical decisions regarding the use of fungicides to protect against both leaf and head diseases.
Fusarium head blight (or head scab), is the single most threatening disease to the profitable production of wheat. Where the disease is a threat, the use of a recommended fungicide during early flowering (within a few days after full head emergence) often reduces the severity of head scab and its associated mycotoxin. Current recommendations are provided in the MSU Extension News article Managing fusarium head blight. Growers are also encouraged to utilize the national head scab prediction model which provides an assessment of risk based on local weather conditions.
While head scab deservedly receives much of the attention, assorted leaf diseases more consistently reduce yields. Fortunately, the timing of a fungicide application for head scab often coincides with reasonable timing for applications against leaf diseases. While earlier applications of fungicides are often promoted against leaf diseases, they are never as cost effective as applications within the window of time between the boot stage and early flowering. This is not only because of the progressing development of the diseases, but it also immediately proceeds the grain-fill period when diseases are most apt to cause yield and quality loss.
Growers electing to use a fungicide would do well to focus their application strategies targeting head scab and have the added benefit of suppressing yield robbing leaf diseases.