Soybean cyst nematodes (SCN) currently cause $1.5 billion in annual yield losses for growers. A primary concern for the industry is that SCN populations are increasingly overcoming the rhg1b resistance gene derived from the PI88788 breeding line, which has been the industry standard since the 1990s. With many current soybean varieties relying solely on this single gene, the pressure on field performance is mounting as SCN populations adapt.
To combat this, agricultural researchers are working to diversify genetic resistance. Companies like Pioneer are developing new native traits to be stacked with proven technologies such as Peking resistance. This strategy aims to improve durability and provide growers with more options for rotating SCN traits in their production cycles. These products are scheduled for release in the near future.
Management starts with testing. Agronomists recommend retesting infested fields every six years to monitor population levels and resistance patterns. Because SCN damage often mimics other field conditions or exists without visible symptoms, regular soil sampling remains the most effective diagnostic tool. A 2021 study indicated that over 80 percent of sampled fields in the Corn Belt contained SCN, with 35 percent reaching levels capable of causing severe crop damage.
When populations reach high levels, crop rotation is a primary control tactic. Planting corn, alfalfa, or small grains deprives the nematode of a host, which forces the population to decline. Growers must also control weed hosts like purple dead nettle and henbit to ensure the rotation succeeds. Additionally, nematicide seed treatments such as Victrato provide a way to lower cyst numbers on roots when used alongside standard fungicide and insecticide packages.