Are Fungicides a Good Investment for Your Corn Crop?

Once you’ve planted your corn, the next two priorities you’re tasked with are 1) keeping your fields clean; and 2) keeping your crop healthy. 

One tool you have available to help maintain a healthy corn crop are fungicides.

And while fungicides won’t produce higher yields in your crop, they can help protect your yield by preventing and fighting a variety of leaf diseases that pose a threat to your corn crop throughout the growing season.

How to determine the value of a fungicide

Before we discuss fungicides any further, let’s take a moment to understand why leaf diseases can be so detrimental to corn. 

The reason is because decreased healthy green leaf area means less photosynthesis. That translates to less carbohydrate production and thus less sugar transportation to the ear. Less sugar means a decreased ability to make grain, and you’re left with lower yields come harvest. 

It is especially important for you to protect the upper 8-10 leaves of a corn plant, as these are critical for photosynthesis and reaching yield potential.


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So how do you decide if a fungicide application is beneficial for your fields? You should take the following into account:

  1. Pay special attention to the hybrids you’ve planted. Each hybrid has a specific disease rating for fungal diseases and these can help you know if your corn is susceptible to certain diseases.
  2. Note your crop rotation and tillage practices. If disease has been present in your fields in the past, it could easily have left some residue behind. Rotation and tillage can help lessen the likelihood of reinfection, but if these aren’t in practice, a fungicide may be beneficial for your fields.
  3. Know your crop prices and yield potential. For every crop input, there’s a balance to understanding the return on investment it brings. If commodity prices are low or a particular field has already experienced other stress that may impact yields, a fungicide application may not be necessary.  

What are your options when selecting a fungicide?

When considering a fungicide application in your corn, there are two categories to choose from according to your specific needs:

Curative Fungicides

This category includes the Triazoles (Group 3). These fungicides won’t cure an established infection, but they will work to inhibit early growth of a disease. Fungicides such as Prosaro® 421 SC and Tilt® are included in this class. 

Preventative Fungicides

This category includes the Strobilurins (Group 11). These fungicides are designed to prevent infections before they start, and include products such as Headline® SC and Quadris®.

Most fungicide labels recommend using an adjuvant—either a non-ionic surfactant or a crop oil concentrate—in your tank mix to potentially help the fungicide last roughly 14-21 days. 

To maximize the benefits of a fungicide application in corn, it’s best to apply as close to the tassel stage as possible. 

If an earlier fungicide application is warranted, remember that the residual benefit may not last through the key grain fill part of the growing season.

Take care of your management needs with FBN Direct℠

You can double down on savings and convenience when you shop for ag chemicals on FBN Direct. Simply buy the crop protection products you need online and get them shipped directly to your farm—or schedule free pick-up at your local FBN Hub. It’s just one of many different ways we’re making farming better for farmers.

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Prosaro® 421 SC is a registered trademark of Bayer CropScience. Tilt® and Quadris® are registered trademarks of Syngenta Crop Protection, LLC. Headline® SC is a registered trademark of BASF Ag Products.
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