Press Release •  5/18/2021

43% of Growers Have Medium to High Corn Nematode Pressure in Their Fields, Poll Shows

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Levels Are Consistent With Likely Yield Loss in a Season When Corn Prices are Soaring

JOHNSTON, Iowa -- With corn planting nearly complete and commodity prices historically strong, growers’ attention has shifted to closely monitoring emergence. Thin stands or uneven plant heights signal trouble, and according to the results from a recent grower poll by Pioneer, a potential cause could be corn nematode pressure.

In late April 2021, Pioneer surveyed U.S. corn growers, asking: “What is the corn nematode pressure level in your fields?” The responses from 448 growers across the country saw 32% answer “low pressure”, 31% answer “moderate pressure”, 12% answer “high pressure” and 25% answer “I don’t know.”

“More and more farmers are becoming aware of this problem and understand the need for knowing levels in their fields,” said Mary Gumz, Pioneer Agronomy Science Manager. “When I look at what they said about their nematode pressure, 43% have either medium or high nematode pressure -- the level of pressure that can really start affecting yields. It's definitely a problem that needs to be addressed.”

Corn nematodes are parasitic worms that cause significant yield loss by damaging roots, impairing water and nutrient uptake and creating entry points for pathogens. The dry soils many farmers are experiencing only worsens the impact. For those growers with nematode pressure, Gumz shared three tips to help mitigate:

  1. Control weeds. Many weeds can act as an alternate host for corn nematodes.
  2. Rotate crops. Pioneer has found that in rotated fields, farmers were less likely to have high corn nematode pressure.
  3. Use a premium seed treatment. Gumz recommends Lumialza™ nematicide seed treatment, which not only shield roots from nematodes, but also helps improve water and nutrient absorption.

Gumz says she is encouraged that 75% of growers who responded had checked their fields for nematodes before but was still concerned about those who answered that they didn’t know the pressure levels in their fields, especially in light of a recent field study she completed.

“My advice for them would be to take those soil samples for nematode pressure and get their soils tested,” said Gumz. “Last year in southern Illinois, we did a large corn nematode survey, and found that 93% of fields had corn nematodes. So, farmers might be surprised at how much nematode pressure they already have in their fields.”

Growers can contact their local Pioneer agronomist to help accurately measure nematode pressure levels in their fields using soil sampling. More information on premium seed treatments for corn, such as Lumialza nematicide seed treatment, can be found on or by contacting their local Pioneer sales representative.


About Pioneer
Pioneer, the flagship seed brand of Corteva Agriscience, is the world’s leading developer and supplier of advanced plant genetics, providing high-quality seeds to farmers in more than 90 countries. Pioneer provides agronomic support and services to help increase farmer productivity and profitability and strives to develop sustainable agricultural systems for people everywhere.

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About Corteva Agriscience
Corteva Agriscience is a publicly traded, global pure-play agriculture company that provides farmers around the world with the most complete portfolio in the industry - including a balanced and diverse mix of seed, crop protection and digital solutions focused on maximizing productivity to enhance yield and profitability. With some of the most recognized brands in agriculture and an industry-leading product and technology pipeline well positioned to drive growth, the company is committed to working with stakeholders throughout the food system as it fulfills its promise to enrich the lives of those who produce and those who consume, ensuring progress for generations to come. Corteva Agriscience became an independent public company on June 1, 2019 and was previously the Agriculture Division of DowDuPont. More information can be found at

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Media Contact:
Kacey Birchmier
515-305-0085 cell