The soybean cyst nematode (SCN) is one of Iowa’s most serious and persistent soybean pests. The nematode has the potential to cause devastating yield losses, population densities can increase very rapidly within a single growing season, and dormant eggs can survive for more than a decade in infested soils in the absence of soybeans. Random surveys funded by the soybean checkoff in 1995-1996 and again in 2006-2007 revealed that 70 to 75 percent of fields in Iowa are infested with the nematode.