Symptoms occur on the head after flowering. Individual spikelets or the entire head appear prematurely bleached. Superficial pink or orange fungal growth may be associated with the bleached areas. The fungi causing scab are in every wheat field every year, but favorable weather conditions are needed for severe disease.
Florets become infected at flowering, and the fungus kills individual spikelets or the entire head.
The bleached spikelets usually contain shriveled grain. Scabby grain may contain one or more toxins produced by some Fusarium species, and may be docked at the elevator. Most of the scabby grain is very light weight and can be separated from the healthy grain. Scabby grain should not be fed to livestock, especially hogs, because of the potentially lethal effects. If a scabby seed lot must be used for planting, a fungicide seed treatment should be applied before planting.