Soybean Sudden Death Syndrome Identification and Prevention

4 Minute Read Time | Field Check Up Findings

The past couple of years have been tough for farmers in western Missouri, and after a cool, wet spring, this season wasn’t looking any better. But a long-awaited break in the weather turned things around and crops finally took off. “The beans are looking phenomenal except for the sudden death syndrome,” Channel Seedsman Brad Veale says.

Brad wasn’t surprised to see the condition this year. Two factors can make plants more susceptible to the infection:

• Cool, wet weather after planting

• High yield potential

Farmers in his area experienced both this season. After cold fronts, rain and an unexpected May snowstorm disrupted planting this spring, conditions improved and farmers were looking forward to a productive harvest. Brad knew it was a matter of time before sudden death syndrome set in.

Sudden Death Syndrome

A fungal disease caused by fusarium virguliforme, aka sudden death syndrome (SDS), is a major yield threat to U.S. soybean farmers.¹ While the symptoms of the disease are most identifiable during the late vegetative or early reproductive growth stages, the initial infection occurs shortly after germination.

"That’s the kicker,” Brad says. ”There’s nothing you can do at that point.”

Diagnosing the Disease

Brad first noticed something was awry in early August when leaves started to prematurely yellow. It wasn’t until he got out into the fields that he confirmed what his gut told him was true. During a Field Check Up Series visit, he split the stalks open to make the diagnosis.

“You want to be sure you diagnose it correctly,” he says. “Brown stem rot is another disease we see in this part of the world, and the leaves look about the same for brown stem rot and SDS symptoms. If you split the stalks open and you see white, it’s SDS. If it’s brown and rotten, that’s brown stem rot.”

SDS can spread rapidly after the initial symptoms appear. The telltale yellow blotches expand into larger, brown patches. Leaves can eventually drop and flowers and pods may abort. As with most diseases, potential yield loss is greatest when foliar symptoms appear earlier in the life cycle.

“You don’t have to look very far to see it. Just about everybody has it. There doesn’t seem to be any one place that doesn’t,” Brad says.

Monitoring the Problem

“SDS comes with a lot of uncertainty,” Brad says. Now that he’s identified the problem, he uses drones and field health imagery from the Climate FieldView™ platform to monitor conditions. As the disease progresses, he helps farmers get a handle on the impact and plan for next year.

In spite of the SDS pressure and uncertainty, Brad is looking forward to harvest. “The question on everybody’s mind is how much yield loss they're going to see,” he says. “It's really hard to quantify that. There’s going to be some loss, but there’s still going to be a good bean crop."

SDS Management

Once you’ve experienced SDS in your fields, you are likely to face it again. Your Channel Seedsman can help you reduce the potential for future infections with the following:

• Consideration should be given to improve field drainage through tiles or field leveling.

• Soil compaction should be addressed with appropriate deep tillage and management practices that reduce the potential for creating compaction.

• Soybean products should be reviewed and selected based on SDS tolerance and resistance levels.

• Earlier maturing products may reduce disease impact.2

• Seed should be treated with a fungicidal seed treatment.

• Consider planting later in the season when soils may be drier and warmer.

• Foliar fungicides have not been effective.

Brad advises farmers to take a closer look at planting dates and seed treatments. Early planting increases the risk, but he says the higher yield potential offsets damage from SDS. Seed treatments can help. “If you’re going to plant early, you need to use a seed treatment,” he says. “If you have a field that gets knocked by it every year really bad, that’s probably a candidate for later planting.”

References:

1. Jardine, D.J. 2020. Sudden death syndrome. Soybean Diseases. Soybean Research & Information Network. https://soybeanresearchinfo.com/.

2. Meiring, B., Dorrance, A., and Mills, D. 2011. Sudden death syndrome of soybean. AC-44. Ohioline. The University of Ohio State. https://ohioline.osu.edu/.