Sampling for Nematodes Before Planting Sweet Potatoes


A fairly new species of nematode is making itself known in the southeast, particularly in sweet potato production.  North Carolina Department of Agriculture Regional Agronomist Don Nicholson explains:

“Well, we’re just seeing a newer nematode coming on the scene the last few years, especially affecting sweet potatoes, which is a staple crop in my region.  It’s pretty much in the same family as the Incognito, or the root knot nematode that we’ve been accustomed to for as long as I can remember that we’ve learned to manage, but this nematode is in the same family that’s called enterlobii.  It’s a particularly nasty nematode that does particularly nasty things to a sweet potato, and other crops that we grow, soybeans, tobacco, and also weed species.  It’s potentially a game changer in what we grow and how we grow it in eastern North Carolina.”

Let’s talk about what needs to happen to at least beat this pest back.

“Well, first of all, I think if you’re in a sweet potato growing region in the state, you probably need to be taking nematode samples, if you’re not already, and find out if you have root knot nematode.  And if you do, Dr. Weimin Ye, the nematologist in our lab, can run a DNA sequence on it and see if its root knot or incognito or enterolobii, because microscopically they look identical and you can’t look at them under a microscope and say it’s enterolobii or incognito, so he’s developed a DNA sequence and program to determine exactly which one it is. 

“And going forward, I think rotation is going to be another tool, it doesn’t seem to attack or live off of any of the grasses, corn, grain sorghum, sorghum sudan, millet, that kind of thing.”

In those circumstances you’re not actually eliminating them, you’re just beating them back.

“Yeah, you’re just trying to get that population down.  It’s particularly helpful in tobacco.  Peanuts seem to be fairly resistant to it thus far, don’t have a lot of information on that yet.”

Don Nicholson, Region 7 Regional Agronomist with the North Carolina Department of Agriculture.

Read more about how nematode could impact sweet potatoes via

A native of the Texas Panhandle, Rhonda was born and raised on a cotton farm where she saw cotton farming evolve from ditch irrigation to center pivot irrigation and harvest trailers to modules. After graduating from Texas Tech University, she got her start in radio with KGNC News Talk 710 in Amarillo, Texas.