The Soybean Cyst Nematode (SCN) continues to cause significant damage to U.S. soybean production, with annual yield losses estimated at $1.5 billion. Experts warn that the problem is worsening as the pest adapts to widely used resistance genes. University of Nebraska Extension Plant Pathologist Dylan Mangel, a member of the SCN Coalition, explained that years of overreliance on the PI 88788 resistance source have allowed the nematode to evolve and overcome its effectiveness.
To address the issue, more farmers are now planting soybean varieties that use the Peking source of resistance, which has proven more effective than PI 88788. However, researchers caution that because Peking applies stronger selection pressure on nematode populations, it may lose effectiveness more quickly. Current data suggest that the Peking resistance source could begin to break down sooner than its predecessor, raising concerns about the longevity of available control methods.
The agricultural industry has faced difficulties in developing new sources of resistance, as promising candidates often fail to produce strong yields, limiting their commercial potential. Until new genetic defenses become available, experts recommend rotating between existing resistance sources and conducting regular soil testing to monitor nematode levels. These management practices are seen as essential steps to maintaining yield stability and protecting the long-term health of U.S. soybean fields.
