In MN temperatures have fluctuated greatly within the past few weeks.
Despite this, the overall spring wheat crop looks to be doing well in terms of disease. In many areas spray applications for FHB are being contemplated at this time. The risk model is trending high risk in the Northwestern part of the state for super susceptible varieties e.g. Mayville. The two day forecasting for moderately resistant varieties is low to moderate risk .
Despite this, many areas are experiencing periods of high relative humidity after storm events. Premature discolouration of awns, indicating FHB infection, is prevalent in these areas. Therefore, use of fungicide to control FHB for moderately resistant varieties should also be considered.
Applications should be made at early flowering (Feekes 10.5.1). If not possible at this time, applications up to five days post-flowering have been shown to have some efficacy. Always check current labels for pre-harvest interval and other use restrictions.
–Madeleine Smith, Plant Pathologist, University of Minnesota
For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu
Source: Scab USA