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Catch nematodes before it's too late.

Agronomy Bulletin 91 ─ Corn Nematodes

Many species of corn nematodes feed upon a plant's root system, compromising root system efficiency.

Situation

Corn nematodes are plant parasites that exist in every field to some degree. Yield loss varies by nematode species and their populations. Collecting and submitting samples for plant parasitic nematode analysis is the only way to evaluate your exposure.

Factors to Consider

  • Diagnosis
  • Sampling strategy
  • Submitting samples

Action Plan

  1. Diagnose symptomatic areas. Symptoms of a corn nematode infestation include stunting, yellowing and root deformity, which make diagnosis difficult because the symptoms are similar to those caused by other pests or environmental stressors. Collect samples from symptomatic areas of a field, including around the perimeter where symptoms are less severe and where nematodes are more likely to be found. Avoid sick or dead plants in the center of hot spots.
  2. Follow proper sampling protocols.
    Laboratory requirements: Contact your local lab to determine its sample submission requirements. Labs typically charge a fee per sample and require a sample submission form.
    When to sample: Sample for corn nematodes about four to eight weeks after planting, while plants are small with shallow roots.
    How to sample: Probe through the root zone at an angle at 6 to 8 inches deep. Because corn nematodes can be found inside the root, include root material in the sample. Watch this video for helpful tips on corn nematode sampling.
    Sample size: For each sample, collect approximately 20 cores; each sample should represent less than 40 acres.
    Preparing samples: Label all samples, double-bag in sealable zipper-top bags and refrigerate until the sample is shipped. The nematodes must be alive for effective analysis.
  3. Submit samples. Package the sample with soft packing materials in a sturdy leak-proof container and include a completed sample submission form. Shipping early in the week helps ensure the nematodes will remain alive when the sample gets to the lab.

Summary

Even without visual symptoms, nematode damage may impact crop yield. Scouting for potential nematode problems is important. Once a diagnosis is made, you will be able to determine if you need to implement any management practices. For more information, contact your local Mycogen Seeds commercial agronomist or trusted agronomic adviser.

Resources

Published on Wednesday, July 31, 2013