Complete Nematode (Corn/Turf) Sample Submission

The PIDC provides identification and counts of the nematodes that feed on grasses (corn and turfgrass).  We provide information about the nematode species, thresholds, and management information.  We can also identify nematodes on other plants, but please contact us for specific sampling instructions.  If you are looking for information on submitting SCN (soybean cyst nematodes) samples please click here.   

Form:  PIDC 32 Plant Nematode Sample Submission

Fee for samples originating in Iowa:   $40.00  do not send payment with your sample.  You will receive a statement from Iowa State University.

  • Samples from outside of Iowa:  do not submit without contacting us as we have strict limitations on soil movement. Fee for out-of-state samples: $45.00

Complete nematode counts

Complete nematode counts are counts of the common grass-feeding nematodes.  We provide genera-level identification and how many of each genus are in your sample.  We also provide information on thresholds and if management is warranted.

How to collect samples from corn:

  • Ideally, corn nematode sampling is done between V6 and V12, but it can be done up to R3. For more, read this article
  • Collect 10 or more twelve-inch-deep soil cores from the root zone of unthrifty plants.
  • Do not mix, break up, or otherwise disturb the soil cores.
  • If before the V6 corn growth stage, also collect 5 to 10 root masses from plants; the tops of the plants can be cut off and discarded.

How to collect samples from turfgrass (also see video below):

  • Take samples with a soil probe not a cup cutter
  • 10-20 soil cores
  • Depth of about 4-6 inches – as deep as the grass roots
  • Place cores from green into a sealable plastic bag
  • Be sure to keep sample out of sun and cool prior to shipping (refrigerator)
  • Ship in a box with newspaper or other packing materials to prevent too much shaking
  • If weather is very hot ship overnight.


Shipping samples

  • Place each soil sample in a separate, sealed plastic  bag.
  • If roots are being collected, place in a separate plastic bag.
  • Use a permanent marker to label each bag with county soil collected in, and a field name or sample number that corresponds to the information on the front of the form. We will report counts based on your labeling.
  • Protect the samples from temperatures above 80 degrees. 
  • Do not be physically rough with the samples (by dropping or throwing them into a box or cooler, for example).
  • Deliver or send the samples for processing as quickly as possible; avoid shipping samples on Thursdays and Fridays so that samples do not sit in delivery trucks over the weekend.