Originally written by Emmanuel Byamukama, former SDSU Extension Plant Pathologist, and Shaukat Ali.
Winter wheat has starting flowering (Figure 1). The flowering growth stage is also a time when the risk for Fusarium head blight (FHB or scab) is high. It is important to monitor weather conditions from when wheat is heading until shortly after flowering to decide the need for fungicide application to manage FHB. Application of a fungicide is the only in-season FHB management practice. Rainfall and warm weather during wheat heading through post flowering are the main risk factors for FHB.
The FHB prediction tools (Fusarium Head Blight Prediction Center and Small Grains Disease Tool ) are indicating low risk for the majority of the state for the week of June 7. Both tools use weather variables (rainfall and temperature) to predict the risk for scab.
By using the scab prediction tool correctly, a producer can protect wheat from scab infection by applying a timely fungicide when the prediction tool shows moderate/high risk, hence avoiding dockage or rejection of grain at the elevator due to Deoxynivalenol (DON or vomitoxin). When the tool shows low risk, a fungicide application can be avoided (hence saving money). It is advisable to keep checking the predicted FHB risk until wheat has completed flowering (about six days after flowering) to be out of danger for FHB. Best fungicides to apply to manage FHB include Prosaro, Miravis Ace and Caramaba.
