From Gary Bergstrom – Extension Plant Pathologist – Cornell University
Winter cereal fields in New York should be assessed for incidence of Fusarium head blight symptoms at this time to get some idea of the potential for DON contamination in grain. Incidence has been observed from zero to over ten percent in individual fields. Many fields of spring malting barley emerged from the boot over the past week and were sprayed with triazole fungicides at full head emergence. Other spring cereals have not yet emerged from the boot. Predicted risk of FHB is currently high for spring cereals flowering over the next few days in many areas of New York. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and deoxynivalenol (DON) toxin contamination when applied at full head emergence in barley (anthers begin to appear on barley before heads emerge from the boot) or at at wheat flowering (emergence of anthers on heads). There is an application window of approximately 6 days from the beginning of flowering in which reasonable FHB suppression can be expected. Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain. Triazole applications at flowering should provide adequate protection against early developing rust, powdery mildew, and fungal leaf blotches on flag leaves. Leaf rusts and other foliar diseases are now fairly widespread on wheat and barley in New York. Check the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu/) and your local weather forecast frequently.
