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 percent answer “low pressure,” 31 percent answer “moderate pressure,” 12 percent answer “high pressure,” and 25 percent 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 percent 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:
- Control weeds. Many weeds can act as an alternate host for corn nematodes.
- Rotate crops. Pioneer has found that in rotated fields, farmers were less likely to have high corn nematode pressure.
- 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 percent 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 percent 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.