LSU AgCenter researchers are studying nematode tolerance of some cotton and soybean varieties.

Brooks Blanche, agronomist and breeder — who is cooperating with Charles Overstreet, Extension nematologist — says “We’ve got a split-plot design on six different cotton varieties. We’re applying Telone as one part of the split and no Telone on the other part. So, these plots are side-by-side in the field and we’re making the assumption that nematode pressure will be fairly similar.

“Rather than getting a gall rating to evaluate nematode resistance, the Telone should control all the nematodes in the plots where it’s applied. But we want to see how much lint is lost between the Telone-treated plots and the untreated to determine variety resistance.”

The researchers are looking at soybeans, as well.

“Twenty years ago, soybeans were mostly grown on some of the heavier, marginal ground,” said Blanche. “Today, that’s changed a bit with farmers putting soybeans on more productive, lighter soils.”

Those soybeans are being put on better soils, often following cotton where high nematode levels persist. “So, we’re running the tests to see which varieties can better handle, or tolerate, rootknot and reniform nematodes.

“That way we can say, ‘if you’re going to follow cotton with soybeans, variety X would be a good candidate.’”

Telone is a soil fumigant and will kill all the nematodes in a given plot. So, “we’ll know that a variety can yield 70 bushels in a no-nematode environment. Where we haven’t treated, maybe there will be a 20-bushel yield loss. It’ll be interesting to see how it shakes out.”

e-mail: dbennett@farmpress.com