NC Commissioner Steve Troxler: Watch for Nematode Damage in Sweet Potatoes


With the sweet potato harvest, growers are urged to keep watch for nematode damage and may want to consider molecular diagnostic testing if they are found. This is a service of the Agronomic Services Nematode Lab.

  • We are into harvest season for sweet potatoes and I wanted to talk today about a pest that farmers need to keep an eye out for – root-knot nematodes.
  • Or, more specifically, I should say keep your eye out for root-knot nematode damage because you’d need a microscope to see nematodes.
  • Nematodes are microscopic wormlike organisms in the soil. Some kinds of nematodes are considered beneficial, but root-knot nematodes are destructive to agricultural crops.
  • And the guava root-knot nematode, which is a newer species being found in the state, is highly destructive to sweet potatoes.
  • We are fortunate our Agronomic Services Nematode Lab is able to help sort all of this out – genetically typing nematodes in samples so farmers know exactly what they are dealing with.
  • Our lab offers molecular diagnosis, which is the only way to determine the nematode to the species level.
  • Growers should continue routine monitoring of nematodes in all their fields by submitting predictive samples in early fall.
  • If a high population of root knot nematodes is discovered in one or more of the predictive samples, then the grower should consider resampling the field and requesting molecular diagnosis.
  • Stunting, wilting and yellowing of plants can be a sign of nematode damage. The damage is more readily visible below ground with galls on the plant roots.
  • And, sweet potatoes can look like they have marks all over them, making them unmarketable.
  • North Carolina is the leading producer of sweet potatoes in the country, producing about 55 percent of the crop grow in the U.S. Additionally, we have worked hard to develop international markets for this commodity.
  • It is important that we ensure high quality products are being marketed.
  • Sweet potatoes are an important crop for our state, in the neighborhood of over $323 million.