FHB Update from KY, 05/16/14

The current models are showing moderate to low FHB risk across most of KY, I think that FHB will be a player in fields that have been flowering during the past 4-5 days, assuming rain has occurred. Time will tell, but I have seen similar conditions in past years lead to at least moderate occurrence of FHB/DON in fields. Spraying FHB fungicides in some areas has been hampered by the wet conditions. Data from multiple states over the last few years has shown generally good results in FHB/DON control if applications of Prosaro or Caramba are made even 5 days after the onset of flowering. So some fields that were scheduled to be sprayed, might still benefit. Keep in mind, however, that fungicides only provide modest control of FHB and DON (40-60%) even when timed and applied perfectly. So, have reasonable expectations.

Note, the fungicide label will dictate how late in the seasons applications can be made (see days to harvest restriction section on product labels). Even if spraying is possible, I do not encourage applications later than 5 days past the onset of crop flowering. There simply are no data to support later applications.

--Don Hershman, Extension Plant Pathologist, University of Kentucky

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu