By the Cornelius Seed Agronomy Team

Sudden Death Syndrome (SDS) is nothing new to Iowa soybean growers, but where we’re seeing it this year deserves some attention.

We recently observed SDS symptoms in soybean fields near Hawkeye, Iowa. Historically, SDS has tended to be a bigger concern farther south, and growers in central and northern portions of our footprint haven't always felt the same need to protect their soybean acres against the disease.

After the amount of rainfall we've received this growing season, that may be starting to change.

Why Are We Seeing More SDS?

Sudden Death Syndrome is caused by the soilborne fungus Fusarium virguliforme. Infection can happen early in the growing season, especially when soybeans are planted into cool, wet soils.

The frustrating part is that you often don't know the plant is infected until much later.

Above-ground SDS symptoms typically become noticeable during the reproductive stages. Growers may first notice yellowing between the leaf veins. As the disease progresses, those areas can turn brown while the veins remain green. In severe cases, leaves may eventually drop while the petioles remain attached to the plant.

The heavy rainfall and prolonged wet conditions we've experienced this year have helped create an environment favorable for SDS development. That's one reason we're paying particularly close attention to symptoms appearing farther north than where we have traditionally seen our greatest SDS concerns.

Don't Forget About Soybean Cyst Nematode

When you're investigating a field for SDS, there's another problem worth considering: soybean cyst nematode (SCN).

SDS and SCN can be a troublesome combination. SCN damages soybean roots and can contribute to greater SDS severity in affected fields.

The challenge with SCN is that significant yield loss can occur without obvious above-ground symptoms. That's why soil sampling and understanding your field's SCN pressure are important parts of developing a management plan.

If you're seeing SDS this year, it's worth asking whether there's more happening below the soil surface than you can see from the road.

What Can You Do About SDS Right Now?

Unfortunately, once SDS symptoms appear, there isn't an in-season rescue treatment that will eliminate the disease.

That doesn't mean scouting it now isn't valuable.

The symptoms you're seeing in August can help you make better decisions before the planter rolls in 2027.

As you scout fields, document where SDS is appearing and how severe it is. Pay attention to differences between soybean varieties and areas of the field. If SCN levels aren't known, consider sampling those fields as well.

When planning for next season, management options can include:

• Selecting soybean varieties with strong SDS tolerance
• Managing SCN populations and rotating sources of SCN resistance
• Improving drainage and reducing soil compaction where possible
• Evaluating planting conditions and field history
• Using a seed treatment that provides protection against SDS in fields with a history or elevated risk of the disease

Where Victrato® Can Fit

For higher-risk acres we recommend Victrato® seed treatment from Syngenta. This is available in our Profit Guard Plus treatment package for 2027.

Victrato® contains cyclobutrifluram and provides seed-applied protection against Fusarium virguliforme, the pathogen responsible for SDS. It also provides protection against several plant-parasitic nematodes, including soybean cyst nematode.

That combination is what makes Victrato particularly interesting for fields where SDS and SCN may both be contributing to lost yield potential.

It's important to remember that this isn't something you apply after SDS appears. The management decision happens before the seed ever goes into the ground.

That's why we're encouraging growers who are seeing symptoms now to identify and document those fields. Those observations can help determine where an additional level of protection may make sense next season.

SDS Pressure May Be Changing. Our Management May Need to Change With It.

One growing season doesn't mean SDS will suddenly become a major problem in every soybean field across central and northern Iowa. But seeing symptoms in areas where SDS hasn't historically received as much attention is something we shouldn't ignore.

Every year gives us information we can use to make better decisions the next time around.

Scout it now. Document what you're seeing. Then use that information when making your 2027 soybean decisions.

If you're seeing SDS symptoms or aren't sure what you're finding in your soybeans, reach out to your Cornelius Seed Rep or Agronomist. We can help evaluate what's happening in the field and talk through variety selection, SCN management and whether a seed treatment such as Victrato® makes sense for those acres next season.

Plant It. Profit.