Small Grains Disease and Pest Update 07/09/24

Fusarium Head Blight Risk

I took a few days off over the July 4th Holiday weekend. The risk for Fusarium head blight did not; the risk for spring wheat varieties with a rating of 6 or worse continues to be moderate to high across all of Minnesota through the end of the week  (Figure 1). The marked difference in the risk of infection between highly susceptible and moderately resistant varieties remains the same (Figure 2). 

Figure 1. Fusarium head blight risk for very susceptible varieties for July 9 through 12. Darker orange indicates moderate risk and red indicates high risk.

Figure 2. Fusarium head blight risk for moderately resistant varieties for July 9 through 12. Darker orange indicates moderate risk and red indicates high risk.

Have I found FHB? 

It takes about a week for symptoms of FHB to start showing after the initial infection. It was not hard to find FHB in the winter rye, winter wheat, spring wheat, and barley variety trials on the Sand Plains Research Farm near Becker last Wednesday. Likewise, FHB is also present in the winter wheat and winter rye variety trials at the Northwest Research & Outreach Center.  Those infections all occurred three-plus weeks ago when the risk models were reporting low risk yet.  That's concerning.  It will require us to start thinking about how to manage harvest to reduce the amount of DON in the harvested grain that is put in the bin. I'll share my thoughts on harvesting scabby grain in the next post.