A survey of the Wisconsin Winter Wheat Variety Trials indicates that some fields will be at risk for dockage or outright rejection of winter wheat grain later this month. Environmental conditions that lead to high risk coupled with susceptible genetics and the grower’s inability to simply get fungicides applied all contributed to this issue. As we move forward into harvest here are a few point to consider to help mitigate dockage and deoxynivalenol (DON or vomitoxin) risk moving forward.
1.
Scout your fields now to assess risk. Wheat near our
Fond du Lac location is maturing making it very difficult to assess the
incidence and severity of the infection. Understanding a fields risk will help
growers either field blend or avoid highly infected areas so entire loads are
not rejected.
2.
Adjust combine settings to blow out lighter seeds and
chaff. Salgado et al. 2011 indicated that adjusting a combine’s fan speed
between 1,375 and 1,475 rpms and shutter opening to 90 mm (3.5 inches) resulted
in the lowest discounts that would have been received at the elevator due to
low test weight, % damaged kernels, and level of the mycotoxin deoxynivalenol
(DON; vomitoxin) present in the harvested grain.
3.
Know your elevators inspection and dockage procedure
(each elevator can have a different procedure).
4.
Scabby kernels does not necessarily mean high DON
levels and vice versa.
5.
DON can be present in the straw so there is concern
regarding feeding or using scab infected wheat straw. DO NOT use straw
for bedding or feed from fields with high levels of scab (Cowger and Arellano,
2013).
6.
Do not save seed from a scab-infected field. Fusarium graminearum can be transmitted
via seed. Infected seeds will have decreased growth and tillering capacity as
well as increased risk for winterkill.
7.
Do not store grain from fields with high levels of
scab. DON and other mycotoxins can continue to increase in stored grain.
8.
For more information on Fusarium head blight, visit
this information page: http://fyi.uwex.edu/fieldcroppathology/fusarium-head-blight-scab-of-wheat/
Cowger,
C., and Arellano, C. 2013. Fusarium graminearum infection and
deoxynivalenol concentrations during development of wheat spikes.
Phytopathology 103:460-471.
