South Dakota Soybean Checkoff Pays to Test for Growing SCN Population

Soybean cyst nematodes reduce yields and profits while sometimes avoiding detection for years.

“They feed on the roots of soybeans and actually form little cysts that hold the eggs on the outside of the root where the female was feeding,” said Dr. Madalyn Shires, plant pathology specialist at South Dakota State University.

Soybean cyst nematode is a significant pest and pathogen for soybean growers, according to Shires. No county in eastern South Dakota has avoided soybean cyst nematode infestations.

“Our numbers have been increasing dramatically with the last three years of drought that we’ve had,” she said. “The SCN is able to reproduce more generations each year whenever it’s hot, so our average numbers have really, really been increasing, especially over the last two years.”

Testing to determine whether a field has SCN is easy, according to Shires, who says the most accurate tests happen at harvest time but can take place any time the ground isn’t frozen.

“We recommend that producers take soil samples, the standard is 20 soil cores per every 20 acres of the field. Those soil cores can then be put together into one bag and sent to our South Dakota Plant Diagnostic Clinic,” said Shires. “For South Dakota producers specifically, our SCN testing is actually free, sponsored through a grant from the South Dakota Soybean Research and Promotion Council.”

The South Dakota Soybean Checkoff also pays for HG-typing when SCN populations are particularly heavy. HG-typing provides a picture of what soybean variety is allowing an SCN population to thrive.