Base SDS seed treatment decisions on economics

Soybean Pest Beat: Let return on investment guide “treat or don’t treat” decisions for sudden death syndrome. 
Jan 04, 2022
It will cost $8 to $10 per acre to apply an extra seed treatment for sudden death syndrome in soybeans. We had some in ’21 but normally don’t see much. Is the treatment worth the cost? Should I just put it on certain fields?
The Indiana certified crop advisers panel answering this question includes Steve Gauck, a regional agronomy manager for Beck’s, Greensburg; Jeff Nagel, an agronomist with Ceres Solutions, Lafayette; and Dan Ritter, an agronomist with Dairyland Seed, Rensselaer.
Gauck: There are ways to help determine when and where SDS will rob yield. Look at the natural tolerance your soybean varieties have to SDS. Plant soybeans with a good tolerance first and in fields with a history of yield-limiting SDS pressure. Since infection happens early, these soybeans would be a target for a seed treatment. Many high-yield soybeans don’t have natural resistance to SDS. So, plant these soybeans in mid- to late season on well-drained soils. Seed treatments show value on fields with a history of SDS, wet soils and in fields planted early.
Nagel: In the disease triangle, three things interact for disease to develop: the presence of a pathogen, a susceptible host crop and favorable environment or weather.
Once SDS occurs in a field, the pathogen which causes sudden death syndrome, Fusarium virguliforme, will overwinter on soybean residue and in the soil. Therefore, decide how you want to approach managing SDS to mitigate risk of yield loss.
Evaluate varieties you plan to plant in 2022 and look up ratings on SDS. This will give you some insights on susceptibility to SDS. Also note soybean cyst nematode ratings. SDS can be more severe with SCN due to a compromised root system, making plants more vulnerable to SDS root infection.
To complete the disease triangle, you need favorable conditions for SDS infection and development. SDS is a root rot and infects the root system in the early vegetative stages, sometimes within days after germination. Cool and wet soils favor infection. If you plant beans in April, risk might be increased. Rainfall events during the reproductive stages can allow the disease to increase production of toxins that are translocated to the leaves, causing leaf scorching. Generally, the earlier this occurs in the reproductive stages, the greater the yield reductions.
If you will plant a variety that offers low SDS protection into a field with a history of SDS somewhere, add either Saltro or Ilevo seed treatments. Both can help reduce the impact of SDS when it occurs and suppress SCN to some extent.
Ritter: Sudden death syndrome can be a costly disease. At today’s prices, we’re talking about 1 bushel per acre or less to pay for added treatment. Keep that in mind as you consider options. Do you feel you lose more than a bushel an acre from SDS? If your SDS levels are fairly low to non-existent in certain fields, then you may forego the treatment.
Consider using it in high-risk environments such as early planting, compacted fields or those with a strong history of SDS. Given soybean value and the value of SDS treatment, it just doesn’t take much risk of loss to make numbers work in your favor.