Now is the time to make a critical fungicide spray decision on winter malting barley. Winter barley in New York has either reached full head emergence or will do so in the next few days The Fusarium Risk Assessment Map (http://www.wheatscab.psu.edu) currently indicates a low risk of Fusarium head blight (FHB) across the state, but this could change with rain showers and thunderstorms in the forecast. Maximal suppression of FHB and grain contamination by deoxynivalenol (DON) mycotoxin results when fully emerged heads of winter malting barley are sprayed with DMI (FRAC Group 3) containing fungicides Caramba, Prosaro, or Miravis Ace (latter includes FRAC Group 7 fungicide). A heads-emerged spray with these fungicides also protects upper leaves against fungal leaf blotches, powdery mildew, and rusts. Foliar sprays of any of these three products up to seven days after head emergence may still result in significant FHB and DON suppression.

Winter wheat development in New York ranges from flag leaf just visible to boot stage and is expected to initiate flowering over the next two weeks; the crop is further ahead in the Hudson Valley than in western New York. The DMI (FRAC Group 3) containing fungicides Caramba, Prosaro, or Miravis Ace (latter includes a FRAC Group 7 fungicide) are the most effective fungicides for suppression of Fusarium head blight (FHB) and deoxynivalenol (DON) mycotoxin contamination when applied at flowering (emergence of yellow anthers on heads). A flowering application of these fungicide products should be based on FHB risk as well as the risks of powdery mildew, rusts, and fungal leaf blotches in the upper canopy based on scouting of individual fields. There is an application window of approximately 7 days from the beginning of flowering in which reasonable FHB and DON suppression can be expected. Check the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu) and your local weather forecast frequently as your winter wheat crop approaches heading and flowering.

--Gary Bergstrom, Extension Plant Pathologist, Cornell University