Corn producers who want to control foliar diseases with a fungicide have a new tool. The fungicide Stratego, from Bayer Corp., is now registered for use on this crop. Stratego is a combination of two active ingredients, propiconazole and trifloxystrobin. Propiconazole has been used on corn for nearly a decade as the active ingredient in Tilt fungicide. Trifloxystrobin is a new product in the strobilurin family, which also includes azoxystrobin, the active ingredient in Quadris.

Stratego is applied to corn at a rate of 7 to 12 fluid ounces/acre to control common rust (Puccinia sorghi), eyespot (Kabatiella zeae), gray leaf spot (Cercospora zeae-maydis), northern and southern corn leaf blights (Exserohilum turcicum and Bipolaris maydis), and northern corn leaf spot (Bipolaris zeicola). I have seen good control of these diseases with Stratego, with performance similar to that of Quadris.

The propiconazole component of Stratego offers both benefits and detriments. It provides systemic activity and proven control for eyespot, and is helpful in management of potential resistance to the strobilurin component. However, it also means that the product cannot be applied to corn after silking, the same restriction that once applied to Tilt. Now, Tilt has an exemption in Iowa and other states that allows applications after silking if the crop residue is not fed to livestock. A similar exemption will be pursued for Stratego, but its status has not been determined.

Like any crop protection chemical, there are other restrictions on the use of Stratego.

Read and follow the label instructions before using any fungicide.

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Gray leaf spot and common rust.

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Northern corn leaf blight.

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Corn eyespot.