Plant Health Initiative

Sudden Death Syndrome - Risk

SDS disease tends to be most severe on well-managed soybeans with a high yield potential. Fields with a history of SDS are at risk of re-occurrence.

Infection by the SDS pathogen is favored by

• Slow seed germination and emergence, which prolongs the contact period between pathogen and soybean, promoting infection. These conditions are more likely to occur in early planting than later planting dates.
• High soil moisture during the vegetative growth period
• Unseasonably cool temperatures prior to or during flowering and pod set

Early planting increases risk

There are many research reports which suggest that in a growing season with regular levels of soil moisture, the earlier the planting the higher the risk of SDS.

X.B. Yang, plant pathologist at Iowa State University, has observed in Iowa that soybean fields showing severe defoliation in summer and early fall were likely planted before the end of the first week of May. Rarely, there are cases of severe SDS in fields planted after May 15.

If you have fields with a high SDS risk, consider making a planting route in which fields that have a history of SDS are planted last. Such a plan will avoid very early planting and reduce the risk of disease re-occurrence.