Fusarium Head Blight (Scab)

Fusarium head blight or scab can seriously reduce yields and result in mycotoxin-contaminated grain and low-vigor seed in all cereal crops if moist conditions exist at the time of flowering. A new extension web site called Scab Smart provides up-to-date information on the integrated management of Fusarium head blight.

Symptoms of Fusarium head blight (FHB) on malting barley are less distinctive than what we are accustomed to seeing in wheat.  We are gaining experience with rating barley for FHB and we share this pictorially.  Soft dough stage is the most opportune time to visualize symptoms of FHB on wheat spikes.  We are generally seeing FHB expressed as moderate darkening of individual florets or clusters of florets.  You can see in the photographs by Jaime Cummings that pink Fusarium colonies typically grow, under incubation at high humidity, from portions of the spikes that she tagged as having FHB symptoms.   If only the very tip of the floret is discolored this is usually not due to Fusarium infection. FHB symptoms at soft dough are indicative of infection of the grain by Fusarium graminearum and contamination with the mycotoxin, deoxynivalenol (DON). 

Barley grain is not typically purchased by malt houses at levels exceeding 1 ppm of DON.

a hand holding five heads of wheat with varying degrees of browning

Fusarium head blight on wheat