Please be aware that there are increasing incidences and severity of Fusarium Head Blight (FHB also called head scab or scab) in this year's harvested grain. This disease will cause shrinkage of kernels and sometimes the development of scabby or "tombstone" kernels, which are shrunken white kernels that are covered in fungi and spores. To reduce grain contamination from the mycotoxins associated with this disease, it is important to increase the fan speeds on your combine in order to blow out the affected kernels. This may reduce the level of toxins detectable to more safe levels, below 5 ppm.
I have attached a picture of FHB in wheat that I took west of Idaho Falls. The disease increases in severity in areas where corn is grown and is worse where small grains directly follow corn in the rotation.
I HAVE SEEN IT IN BOTH WHEAT AND BARLEY in Idaho this year.
There may be a brown discoloration of the rachis (the stem portion of the head) seen after flowering that progresses to single florets that then die and become bleached in appearance. This will vary - there may be single florets affected, or one quarter, one third of the head to the entire head bleached and diseased. Partially or totally killed heads may still have green stems, unlike what you will find with take-all or Fusarium dryland foot rot where the entire stem will be bleached. A tell-tale characteristic of this disease is the formation of orange, or pinkish or salmon-colored spores structures that form at the base of the floret at the junction of the seed to the stem. These "sporodochia" may also form at the edges and overlapping joints of the chaff. You may have FHB even without the visible presence of these orange-colored sporodochia.
Please do not mix highly contaminated grain with clean grain - this may only increase the amount of contaminated grain that will be difficult to sell.
Juliet Marshall
Associate Professor, Cereals Pathology and Agronomy
Idaho Falls R&E Center
1776 Science Drive Suite 205
Idaho Falls, ID 83402
208-529-8376 office
208-390-4859 cell
http://www.extension.uidaho.edu/scseidaho/
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