Soybean cyst nematodes (SCN) are often labeled “the billion dollar pest” because that’s roughly their economic impact. Further complicating the issue, SCN damage can be mistaken for other problems, such as nutrient deficiencies, plant diseases, herbicide injury or even drought stress. But make no mistake – the damage can add up.
And while SCN can never fully be eliminated from an infested field, farmers do have several tools at their disposal. In particular:
- Plant health maintenance – healthier plants can somewhat “outgrow” SCN problems.
- Sanitation – delay the spread of SCN into new fields by cleaning equipment and avoid planting seed grown on infested land into non-infested fields.
- Host resistance – some soybean varieties are SCN-resistant.
- Non-host crops – rotating to corn, oat or alfalfa “non-host crops” can cause a decline in SCN populations.
- Nematicides – several soil-applied nematicides and seed treatments are labeled for SCN management but do not provide season-long control.
One of these tools is in danger, according to Iowa State University plant pathologist Greg Tylka.
“I have observed a slow but steady decrease in effectiveness of PI 88788 resistance against the soybean cyst nematode in Iowa over the past 15 years, and it is becoming a serious concern,” he says.
PI 88788 has commonly been deployed as a source of genetic resistance to SCN, Tylka says. Overuse of this genetic material has put it at risk of losing its effectiveness, he says.
“Midwestern soybean farmers desperately need another type or source of resistance against this widespread pest,” he says.
In the video below, Tylka walks through best practices for collecting soil samples to determine the severity of SCN in your fields.