Cysts are dead SCN females that contain eggs. A cyst may contain 200 or more eggs when it is first formed. Cyst and egg counts generally correlate well with each other, and cyst counts can be loosely converted to egg counts by multiplying the cyst count by a factor of 50 to 100 eggs per cyst. Juveniles typically are short lived and their numbers may not be well correlated to the number of cysts or eggs in the soil. Consequently, it is much more informative to have cyst or egg counts done rather than counts of juveniles when monitoring SCN population densities in the soil.
Some laboratories offer both cyst and egg counts, whereas many others only offer egg counts.
The processing fee for cyst counts typically is less than for egg counts, but cyst counts do not provide as much information as egg counts because of the variable number of eggs per cyst. SCN cyst, egg, or juvenile counts typically are reported per a certain volume of soil. When attempting to compare results of different soil samples, it is important to make sure that results are expressed in similar amounts of soil. To convert from 100 cc of soil to 250 cc of soil, simply multiply the number of cysts or eggs per 100 cc of soil by 2.5. Conversely, to convert the number of cysts or eggs per 250 cc of soil to 100 cc of soil, simply divide the result by 2.5.