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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
P53 - Fusarium crown rot of wheat: a survey of
Minnesota wheat fields
R. Dill-Macky, E. J. Koeritz, B. Zagaran
University of Minnesota, 495 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, MN 55108, USA
E-mail: ruthdm@umn.edu
Crown rot (CR), a common disease of wheat, is caused by Fusarium species,
including Fusarium graminearum and F. culmorum. These same fungi incited
devastating Fusarium Head Blight (FHB) epidemics in the USA’s Upper Midwest
over the past two decades. The symptoms of CR, like many root diseases,
frequently go undetected. It is likely that CR is present every growing season in
Minnesota leading to thinner stands, reduced tillering, fewer kernels per head and
reduced kernel weights. It is estimated that root diseases cause crop losses of 3-
5% in an average year. As CR compromises the root system, greater losses
would be expected in years where environmental conditions favor CR
development early in the season and when late-season moisture stress
exacerbates the impact of the disease.
Despite of the potential importance of the root diseases, virtually no research has
been conducted recently on the impact of the root diseases of wheat in our
region. In 2012, we established a project to determine the importance and
relative frequency of root diseases, including CR and common root rot (Bipolaris
sorokiniana), in wheat in Minnesota.
In 2012, we conducted a survey across the wheat production region of the state,
collecting samples from over 50 fields. Observations of the root systems made in
the field suggest that root diseases, including CR, were more prevalent than we
anticipated with most fields having plants showing visual symptoms of root
diseases. We estimated that over 20% of tillers had died prematurely as a result
of root disease in the most severely impacted fields. CR appeared to be the most
prevalent disease based on the visual observation of symptoms. Plating of crown
tissues on semi-selective media was conducted to determine the fungal
pathogens present, confirming our field observations. A number of Fusarium spp.
were isolated from the collected samples.
Keywords: Fusarium, crown rot, wheat
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