Wheat Fungicide Update

Wheat Fungicide Update

May 16, 2008

Also see this week . .
Wheat Disease Update
Wheat Condition Update

In addition to Proline (prothioconazole, Crop Watch, March 7, 2008), Folicur (tebuconazole, Bayer CropScience) can now be used to suppress Fusarium head blight (FHB) and rust diseases on wheat and barley.

Folicur should be applied in a minimum of 10 gallons of spray solution per acre by ground and a minimum of 5 gallons per acre by air. A maximum of 4 fl oz. of Folicur per acre per crop season may be applied. The pre-harvest interval is 30 days. For suppression of FHB, the optimal application timing is when main stem heads have fully emerged (Feekes 10.5) on 50% of plants. For rust control, apply Folicur when rust pustules first appear on leaves. For optimum disease control, tank mix Folicur with the lowest specified rate of a spray surfactant. Two to four hours of drying time on plant foliage is required for Folicur to become resistant to weathering caused by rain or irrigation.

Proline and Folicur can be tank mixed at reduced rates of 3 fl oz/ac Proline and 3 fl oz/ac Folicur for suppression of FHB and control of leaf diseases in wheat. Optimal timing of Proline + Folicur for suppression of FHB is at 15% flowering (Feekes 10.51). Thorough coverage of wheat heads is essential for maximum suppression of FHB. To control leaf diseases (Septoria leaf and glume blotch, tan spot, and the rusts), apply Proline + Folicur as a preventive foliar spray when disease symptoms first appear on leaves or stems. A maximum of 4 fl oz of Folicur per acre per crop year may be applied. No more than 4 fl oz of Proline per acre per crop season may be applied in tank mixture with Folicur. The pre-harvest interval for Proline + Folicur is 30 days.

Stephen Wegulo
Extension Plant Pathologist