When infection is severe SCNs cause stunting, yellowing, impaired canopy development, and yield loss.

[RM 1][3] Due to the slight stunting and yellowing, many farmers may mistake these symptoms as environmental problems when in fact they are SCNs.

[5] Due to the fact that soybean cyst nematodes can only move a few centimeters in the soil by themselves, they mostly are spread via tillage or plant transplants.

The later the roots are pulled the harder it will be to diagnose due to the SCNs female dying and turning a much darker color, forming a "cyst".

In contrast, the adult male regains a wormlike shape, and he leaves the root in order to find and fertilize the large females.

The eggs may hatch when conditions in the soil are favorable, the larvae developing inside the cyst and the biological cycle repeating itself.

In the autumn or in unfavorable conditions, the cysts containing dormant larvae may remain intact in the soil for several years.

[9] Eggs will still remain inside the female, and when she dies and hardens into a "cyst", they will go into dormancy until the following growing season or until conditions are favorable.

Due to symptoms being hard to spot early on,[RM 1] they can infect a field rather quickly and persist indefinitely.

SCNs can survive in the soil for long periods of time under adverse conditions, can work up on infecting previously resistant varieties of plants,[RM 3] and can never be completely eliminated (only suppressed).

One full year may be sufficient in fields in which the nematode population is low or is heavily parasitized by fungi.