While herbicide-resistant weeds have been in the spotlight, soybean cyst nematode (SCN) continues to silently spread throughout soils in all major soybean-producing states.

Since its arrival in 1954, growers have managed this No. 1 soybean pest by planting SCN-resistant varieties and rotating soybeans with non-host crops such as corn. However, those practices alone no longer effectively manage SCN.

More than 95 percent of soybean varieties use the same source of SCN genetic resistance: PI88788. Much like the overuse of glyphosate in weed management, the over reliance on varieties with PI88788 has exerted selection pressure on SCN. The few nematodes with the ability to reproduce on varieties with PI88788 have multiplied exponentially over the past two decades due to the continued use of these varieties, and SCN’s ability to produce multiple...