The FHB risk models responded as expected, and the risk for FHB infections, depending on the variety's susceptibility to FHB, increased from low to moderate risk towards moderate to high risk. This week's dew points are forecasted to remain high for a couple more days across much of the state. That means hot and muggy conditions during the day, and higher nighttime temperatures at night. Consequently, the risk of FHB infections will remain moderate to high depending on the variety's FHB rating.

Note that the national model indicates a high risk for a greater percentage of the state when compared to the NDSU FHB risk model output for individual NDAWN/MAWN stations. This is an artifact of the weather data used in each model. The NDAWN/MAWN stations used the weather data collected at that station, while the national model uses interpolations of weather data collected from National Weather Service (NWS) weather stations and the NWS weather forecast up to six days into the future.

The NDAWN/MAWN provides a bit more granular look at the risk for fields near the weather station and is probably (slightly) more accurate than the national model, as precipitation has been very spotty up to this point, with some areas being much drier than the national model is indicating in it's risk for infection

This week's advice for Minnesota is as follows; Oats - If you did not apply a fungicide to control crown rust when the flag leaf had just fully extended, apply a fungicide at Feekes 10.5 (fully headed) to protect the crop against crown rust for the remainder of the season. Switch to a premium fungicide to also try to suppress FHB if corn harvested for grain was the previous crop.

Spring barley - Apply a fungicide at Feekes 10.5 (fully headed) to suppress FHB and control net blotch on varieties rated susceptible or very susceptible to net blotch. Use Prosaro or a generic equivalent at a minimum.

Spring wheat - Apply a fungicide at Feekes 10.51 (beginning of anthesis) to suppress FHB. Use Prosaro or a generic equivalent at a minimum, use a premium fungicide if corn harvested for grain was the previous crop, and/or the spring wheat variety is rated susceptible to very susceptible to FHB.

Meanwhile, the scouts are reporting an increase in the incidence of Bacterial Leaf Streak (BLS). This is not unexpected given the weather and the stage of the crop.

--Jochum Wiersma, Small Grains Specialist, University of Minnesota