The soybean cyst nematode (SCN) is capable of causing serious yield loss on soybeans every year. Back in the “good ole days,” a farmer was “good to go” with SCN management if he or she knew what fields were infested with the nematode and then grew SCN-resistant soybean varieties in rotation with the nonhost crop corn. Nowadays, things are more complicated. SCN numbers may be building up and causing increased yield loss and the buildup can go unrecognized because a soybean crop often does not appear stressed above ground, even though yield loss is occurring. This article explains why this SCN numbers might be building up in your fields and how to check.