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Time Your Fungicide Application for Optimal Disease Protection

June 13, 2023
White mold disease on soybean pod

White mold on soybean pod

As we move into summer, disease management and fungicide application plans need to be ready. Proper timing is key to getting the most out of your fungicide and protecting crops from yield-robbing diseases. Environmental stress and damage from diseases such as Northern corn leaf blight or frogeye leaf spot can be devastating to a crop, so it is important to get ahead and take action before these diseases can take hold.

Corn Fungicide Timing

Gray leaf spot disease on a corn leaf

Gray leaf spot on a corn leaf

Northern corn leaf blight, Southern rust and gray leaf spot are all prevalent diseases in corn that can threaten yield potential, but a well-timed fungicide application helps keep them under control, allowing corn to focus on its job of producing high yields.

Some foliar fungicides are only effective when applied before the brown silk phase. On the flip side, an application done too early can be similarly ineffective as other fungicide residuals may not last long enough to prevent the onset of disease. The ideal timing for corn fungicide application is at tasseling or early silking (VT-R1). This provides optimal disease control, preventing its onset at a time when corn is most susceptible to stress.

Thankfully, whether you need to apply early or at VT-R1, Cleaner & Greener fungicides like Miravis® Neo and Trivapro® have greater application flexibility and provide long-lasting residual that protects yield potential from application to harvest.

Soybean Fungicide Timing

Frogeye leaf spot disease on soybean leaves

Frogeye leaf spot on soybean leaves

Common diseases in soybeans include frogeye leaf spot, brown spot and white mold. These and more can threaten yield by damaging the leaves, stems and roots of soybean plants in later stages. As with corn, there is a sweet spot when it comes to foliar fungicide applications that will provide the best ROI potential.

We recommend Cleaner & Greener fungicides, such as Miravis Neo, be applied at the R3 stage, or “beginning pod” stage. This is when the pod is at 1 of the 4 uppermost nodes on the main stem with a fully developed leaf. Stress at the R4 to R6 stages can cause severe reductions in yield, so fungicides applied at R3 provide stronger control during these stages and prevent infection from occurring.

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All photos are either the property of Syngenta or are used with permission.