FHB Update from KY, 05/14/14

A lot of wheat has headed out and has been flowering during spotted to heavy rain over a multi-day period. The current models are showing low FHB risk across the state of KY, but I think the models may be underestimating risk at this time. I have seen them switch from green (low risk) to red (high risk) over a very short time. I suspect this is what will happen in the next few days. The bottom line: 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.

It is my understanding that spraying has been hampered by the wet conditions. All I can say is that 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. 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