Most of the winter wheat in South Dakota is now at flowering. This growth stage coincides with the Fusarium head blight (FHB or scab) disease development. Currently the FHB prediction tool is showing the central parts and a few scattered areas in west SD to have moderate to high risk for FHB to develop. The limited rain for certain areas and high temperatures have lowered the FHB risk. However, change in weather (rainfall and warm temperatures) will affect the risk. Wheat is still at risk of FHB until shortly after flowering. A fungicide labelled for FHB if applied at flowering can lower FHB and vomitoxins (mainly DON) in wheat grain. The best fungicide timing for FHB management is at flowering (50% of the plants have flowers developing). Growers in the areas with the moderate to high FHB risk should consider applying a fungicide to manage FHB. Fungicides that have been found to be effective against FHB include Prosaro, Caramba, and Miravis Ace when applied at flowering growth stage. Growers should keep checking on the prediction tool until wheat is done flowering to decide on the need for a fungicide.
--Emmanuel Byamukama, Extension Plant Pathologist , South Dakota State University
For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu
For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org