FHB Update from NY, 05/19/17

Winter malting barley fields in New York range from in the boot to heads fully emerged. Development is further ahead in the Hudson Valley region. Conditions have been very conducive for local spore production by the Fusarium Head Blight (FHB) fungus. The Fusarium Risk Assessment Map has shown moderate to severe risk for large areas of the state this week and through this weekend. Application of an effective triazole fungicide product, specifically Caramba or Prosaro, is recommended as soon as all of the barley heads have emerged to suppress FHB and DON production as well as to protect upper leaves from foliar diseases. Sprays up to seven days after head emergence may still result in significant disease suppression. Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain. Significant levels of scald disease have been observed in some barley fields. Low levels of powdery mildew and spot blotch have been observed, though no rusts have been seen to date. This is a critical time for triazole fungicide application to winter barley and I urge close observation of crop development and weather forecasts.

Winter wheat in New York is at stem elongation to flag leaf visible stages, so flowering is still about 10-14 days ahead. Some wheat is further ahead in the Hudson Valley. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and DON contamination when applied at flowering (emergence of anthers on heads). A flowering application of triazole fungicide should be based on Fusarium head blight (FHB) risk as well as the risks of powdery mildew, rust, and fungal leaf blotches in the upper canopy based on scouting of individual fields. We have observed low levels of powdery mildew and fungal leaf blotches but no stripe rust or leaf rust to date. There is an application window of approximately 7 days from the beginning of flowering in which reasonable FHB 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

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