The number of cysts in the soil is an indicator of the extent of the SCN infestation, but the number of eggs in cysts varies. Therefore, egg counts are more helpful. Some private and university labs test 250-cc samples. Soybean cyst nematodes tend to be clustered in the field. Thus, different parts of a field could have different infestation levels.
Management depends on the extent of infestation.
If numbers are high, it may be wise to not grow soybeans for several years. If numbers are moderate or low, a rotation of resistant soybeans and corn can be used. After a field is infested, SCNs can exist for more than 10 years even if no soybeans are grown. Low numbers of eggs of nematodes other than SCNs can be recovered from soil samples. Thus, the lab needs to confirm SCNs are present and there were not false positive reports.