Volume
4 Issue 8
July 10, 2007
Discolored Wheat Heads:
Heat, Root Rot, Maggots, or Scab ?
It is not difficult to find discolored wheat heads in fields
throughout the region. There are multiple causes for these symptoms.
Heat:
 Figure
1 illustrates heat damage where symptoms were limited to the
spike and not the entire plant and there was no evidence of root
rot. Poor root development where there was excessive moisture early
in the growing season made these plants susceptible to heat because
water demands exceeded the roots ability to provide moisture.
Root Rot:
 Figure
2 illustrates the symptoms of root rot infected plants.
Root rot infected plants are white or silver to bronze and affect
the whole plant. Pulling these plants by the discolored head will
easily pull the entire plant from the soil because of the very small
root system.
Wheat Stem Maggot:
Figure 2
illustrates the symptoms of a wheat stem maggot infested plant. The
head is bright white while the leaves remain a normal green. The
head is easily pulled from the plant due to the maggot having chewed
the stem completely through just above the node.
Scab (Fusarium head blight):
Scab infected heads are pink to brownish, and often, kills only a
few spikelets. Pink to salmon-colored spores and mycelium may be
found on the margins of the glumes of spikelets infected with scab.
If the whole head is infected, symptoms include discoloration of the
stem right below the head.
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