As the rain in the forecast has diminished so has the risk for Fusarium Head Blight (FHB) in Tennessee wheat.
Wheat that will be flowering this week in Tennessee has low risk of FHB or head scab infection based on the Fusarium Head blight Prediction Center (www.wheatscab.psu.edu) due to the lack of rainfall predicted for the area (image below from www.wheatscab.psu.edu). A note on the forecast website – it is best viewed with the following web browsers: chrome, firefox, and safari (Internet explorer has some compatibility issues that are trying to be resolved).
Wheat that was flowering early last week had increased FHB risk with the warmer temperatures and wet weather. Such earlier flowering wheat could benefit from a fungicide application sometime during flowering (5 to 7 day window starting at initial bloom see previous post for more information – Considerations for fungicide application in wheat). Many university fungicide trials across multiple states have reported that Prosaro and Caramba are the best products currently available for reducing FHB and the mycotoxin it can produce in grain (called vomitoxin or DON – deoxynivalenol). Although these fungicides, like all fungicides, are not going to provide 100% control. Research trials have show that FHB symptoms and DON levels can be reduced by approximately 40-60%, relative to a non-treated check. Multiple factors contribute to this level of control which include fungicide efficacy, application coverage, timing in respect to wheat growth stage (all the heads in a field will not be flowering at the same time), and disease risk (i.e. weather before, during, and after application, as well as field history – wheat planted behind corn is at higher risk for FHB infection). Bottmon line is that fungicides can reduce disease and DON levels, but pairing fungicide with a resistant variety will provide the best protection and both the FHB forecast model, along with your local forecast and information about your own field will better guide fungicide application decisions.
