By Randy Pepin
U of M Extension
SCN, or Soybean Cyst Nematode, considered the greatest pathological risk for soybeans in the United States and can cause yield losses up to 50 percent. A field that appears normal can experience a 10-peercent yield loss from SCN. Southern and south-central Minnesota is the most prevalent area with SCN in this state; however, it has shown up in southern Stearns County and expectations are for it to continue its move north.
How do farmers combat SCN? Planting SCN resistant hybrids helps but is proving to not be the total answer. Longer rotations between soybeans is probably the best answer, a typical corn/soybean rotation is not a long enough gap.
The SCN lifecycle is only 24 days, so there can be up to six generations each year. These small worms burrow into the soybean roots to feed. The males will later move around to breed and the bred females will form a cyst. Each cyst contains up to 250 eggs and in 24 days, it starts over again. To illustrate the population growth of the SCN, if you start with 200 eggs, and if each generation has a 99-percent death rate, in only three generations you will still have more than 39,000 eggs. That is a phenomenal growth rate and makes controlling SCN extremely difficult.
This summer University of Minnesota Extension is offering free lab testing of soil samples for SCN to those who obtain the allocated sample bags. A typical soil test probe will work, take twenty or so 6-8” probes into the soybean roots per field. Contact Randy Pepin at (320) 968-5077, or (800) 964-4929, pepin019@umn.edu, to request a designated sample bag for farmers with soybeans in the Stearns, Benton, Morrison county area to participate in this free lab test.
This test will help you see if you have SCM and help the UMN Extension determine the breadth of SCN in this part of Minnesota. Reports will not identify your farm.