Watch for These Crop Diseases in 2021

Disease Inspection in field

With a new growing season just around the corner, it’s time to look back at the top crop diseases of 2020 to help farmers prepare for 2021.

Nate Wyss, market development specialist at Corteva Agriscience, and Brian Early, Pioneer agronomist, shared their advice on defeating crop disease next season.

What We Saw in 2020

  1. Weather was a wild card.
    Mild temperatures and favorable moisture created a conducive environment for more aggressive foliar disease development.
  2. Tar spot was one of the most troublesome diseases in corn growing regions.
    This is a relatively new corn disease in some Midwest states, like Indiana, Illinois and Iowa. It has also spread to places like northern Ohio, lower Michigan, southern Wisconsin and southeastern Minnesota.
  3. Northern corn leaf blight and gray leaf spot also posed challenges for corn farmers.
  4. Frogeye leaf spot and white mold were common issues for soybean farmers.

2021 Crop Disease Predictions

  1. Tar spot will continue to be problematic for corn farmers, especially those in the Midwest.
    This disease can cause up to 50% yield loss if left untreated. It has a long window and can appear anywhere from late spring to early fall. Be sure to get ahead of it! It’s likely to develop in high humidity and periods of consistent rain when temperatures are about 59 to 70 degrees Fahrenheit.
  2. Gray leaf spot will be troublesome for corn farmers.
    This disease is likely to continue its spread throughout the Midwest in 2021.
  3. Soybean farmers are likely to combat frogeye leaf spot and white mold again.

Start Now to Fight Disease in 2021

  1. Choose the right seed.
    Choose varieties and hybrids that have a high level of resistance to the common diseases you encountered in 2020. Many diseases overwinter in crop residue. Your Pioneer sales representative can help with the appropriate seed selection and treatments.
  2. Treat preventatively, not reactively.
    If you treat disease preventatively, plants won’t have to waste resources fighting infections later. Fungicides also encourage better overall plant health and standability. Aproach® Prima fungicide provides both preventative and curative protection.
  3. Scout early and often.
    Scout on stems and leaves, starting from the bottom up. Symptoms often appear on lower leaves and stems first.
  4. Identify your disease.
    If you’re having trouble diagnosing a disease, send a sample to your state’s diagnostic lab.
  5. Make your fungicide application as effective as possible.
    • Spray at the right time — aim for some time between the tassel and blister stages.
    • Spray the right fungicide for the diseases you need to control.
    • Spray when the weather is right, leaving enough time for the fungicide to become rainfast before the next rain event.
    • Consider a second application if disease symptoms persist.

For next season, it’s important for farmers to evaluate their risk of disease to choose the best fungicide that will work quickly to protect the health of the plant and, ultimately, their bottom line.

Aproach® Prima is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.


More Disease Management Resources

Our Pioneer agronomists provide the latest research and resources on maintaining healthy crops.

Visit the Pioneer Agronomy Library

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Stop the Clock on Crop Disease

Disease moves fast to destroy crop yields. You need a fungicide that works just as fast. Aproach® Prima fungicide has two modes of action and both preventative and curative properties.

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