The stakes are high. SCN is generally considered to be the worst soybean pest in the United States. Since first being detected in North Carolina in 1954, it has spread into virtually all regions where soybeans are grown. Its economic impact is hard to gauge because yields often decline gradually for several years before the cause is detected. Other sources say heavy SCN infestations routinely cut yields by 5 to 8 bushels per acre, unless properly managed.
Many fields have even higher losses.
Difficult to identify Despite the severe damage it causes, SCN is not easy to spot in the field. They often are mistaken for damage from compaction, iron deficiency chlorosis and other nutrient deficiencies, drought stress, herbicide injury, or plant diseases. They just don't yield like producers are expecting. Yield monitors are helping bring those losses to the attention of growers like Ron Heck of Perry, Iowa. Since then, soil tests confirmed that soybean cyst nematodes were at the root of Heck's yield losses.