Soybean Cyst Nematode - Life Cycle

Contributed by Greg Tylka, ISU

The life cycle of SCN has three major stages: egg, juvenile, and adult female. The life cycle can be completed in 4 weeks under ideal conditions (soil temperatures at 75° F)

SCN eggs released from a cyst. Photo credit: Terry Niblack

Eggs develop into juveniles (J1, J2). The J2's hatch and enter the soybean root to feed and grow. The adult females break through the root surface but remain attached to the root. The males leave the root. Adult males mate with adult females on the root surface.

Females then lay 50-100 eggs in an egg mass on their posterior end. Finally, the female fills up with 200 or more eggs. Eventually, the egg-filled female dies and her body wall hardens to form a tough cyst around the eggs.

Cysts of the soybean cyst nematode. Photo credit: Terry Niblack

SCN juvenile stage