AGVISE tested a very high number of SCN Samples this fall at our Benson, MN laboratory. Our recent expansion of the Benson Laboratory helped us to increase our capacity for SCN testing. We want to provide the fastest service possible, but SCN testing is slow, tedious and labor intensive. This is why we encourage sampling in late July and early August when turn-around on SCN testing is 2-3 days.

We have tested samples for SCN from MN, SD, ND, IA and MT. The samples from ND, SD and MT have show SCN presence in only 21% of the samples. The highest count of 31,400 SCN eggs/100 cc soil was from a field in northeastern SD. All samples we received from IA had SCN eggs present, with an average of 5,500 eggs/100 cc soil. The majority of SCN samples we tested are from MN, and the data is shown below.

Below are the management recommendations based on U of M research for various levels of SCN infestations.

If over 10,000 (eggs/100cc soil) occur, then neither a susceptible or resistant soybean variety should be planted until egg density is reduced.

If egg counts are between 2,000 to 10,000, a cyst resistant variety can be planted, but yield loss is still likely to occur.

If egg density is between 200 (or 500) to 2,000, a resistant variety should be planted.

If egg density is below 200 (or 500 if a little yield loss is acceptable), a susceptible variety rather than a resistant variety can be planted. This is because a high yielding susceptible variety in this situation will usually out-yield a resistant variety.

4054