The soybean cyst nematode (SCN) is a serious and widespread pathogen of soybeans in Iowa. In fact, results of a recent random survey in Iowa indicate that SCN may be present in nearly two-thirds of the fields in the state. Unfortunately, many growers do not realize that their fields are infested with SCN. Why? Results of an Iowa State University, soybean-checkoff-funded research project using site-specific farming technology illustrate the hidden nature of SCN yield losses in Iowa fields.