Plant Diseases
Wheat Diseases in Arkansas
Common Root Rot
Common root rot, caused primarily by Fusarlun graminearum and Bipolaris
sorokiniana (formerly called Helminthosporium sativum) fungi, is found
throughout Arkansas, but the amount of yield loss varies greatly from year to
year. Both fungi cause brown lesions on seedling roots and the subcrown
internode (section between seed and crown). Darkening of the subcrown internode
is typically caused by B. sorokiniana . Significant yield loss usually occurs
only when the fungi move into the crown and lower stems. This phase of the
disease is triggered by drought stress that lowers the water potential of the
plant and allows the pathogens to grow into the crown and lower stems. Symptoms
of this phase show as prematurely dead plants scattered in fields crowns and
lower stems will have brown (Bipolaris or pink (Fusarium) discoloration.
No information is available on differences in resistance among commercial
soft red winter wheat varieties. Crop rotation and certain seed treatments may
reduce the seedling phase of the disease but are not effective at reducing the
later crown and lower stem phase. Management practices such as avoiding high
seeding rates and high nitrogen rates may control the later phase by reducing
water stress.
Back to Wheat Disease Management |
