Soil Sampling Guidelines

  1. A sample consists of multiple cores. Nematodes are not evenly distributed in soil, but rather are clumped in distribution. A good rule of thumb is to collect 16-20 ½-inch-diameter cores per area (green, fairway, etc.). Core depth of 4 inches.
  2. If damage is evident, sample near the margin of affected areas. Do not take samples from dead areas. Try and sample turf that is declining, but not dead.
  3. When taking samples from turf that is not yet showing above-ground symptoms, or if sampling before planting, sample in a zig-zag pattern across the area.



  4. Use a zig zag pattern to sample healthy-appearing turf.
  5. Put the soil from each sampled area into a plastic bag and seal it. Nematodes require moisture to survive so drying the soil will kill them. Label with a permanent marker so that the diagnosis can be assigned to the correct area.
  6. Handle samples carefully. Do not expose samples to direct sunlight or heat. Nematodes are sensitive to high temperatures and UV light. Leaving samples on the dashboard of your car or in the back of a golf cart for periods of time can kill them quickly and negatively affect the accuracy of the diagnosis. It is best to keep the nematodes samples in an air-conditioned room until shipping. For shipping and transport, pack the samples well so that shifting is minimized.
  7. Submit the sample right away. Next-day delivery is best. One study found greatest nematode recovery from hand-delivered samples, the next highest from next-day delivery, and the lowest from regular postal delivery. Shipping samples early in the week is best in order to avoid having them sit in a warehouse or on a truck over the weekend.
  8. Consider keeping inexpensive small foam coolers in your trucks/golf carts and even use for shipping, especially in higher temperatures.

RKN Sampling Guidelines

  • Take 4-5 cores per green (or area) that are 1.5 inches in diameter and 2 inches deep.
  • Place in plastic bag, secure shut to retain ambient moisture, label and ship ASAP.
  • Different labs may have different sampling requirements for Root Knot Nematodes; consult with your specific lab for their guidelines.