Microscopic round worms living in the soil, which feed parasitically on roots of the soybean plant. The nematodes use a spear-like mouthpart, called a stylet, to puncture the plant’s root cells so the nematodes can eat their cell contents. That root damage causes the soybean’s growth to be stunted, and the plants turn yellow because of a reduction in nodule fomiation by the nitrogen-fixing bacteria (which normally colonize roots of soybean plants). SCN can combine with a fungus to cause a soybean plant disease known as “sudden death syndrome.” As part of Integrated Pest Management (IPM), farmers can utilize the parasitic Pasteuha bacteria to help control the soybean cyst nematodes. The Pasteuria bacteria must attach their spores (for reproduction) to juvenile nematodes, so that the Pasteuria offspring can consume the SCN when the spores later germinate.