How to identify and manage sudden death syndrome (SDS) in soybeans

Hidden below the surface lurks a stealthy enemy of soybean farmers–Sudden Death Syndrome (SDS). This soil-borne fungus, the second most devastating disease in soybean production, silently steals yield potential before revealing its presence with telltale yellow leaves. But knowledge is power, and this guide dives deep into SDS, equipping you with the tools to identify, manage, and ultimately conquer this yield robber.

Get ready to learn about:

1. The life cycle of SDS and its devastating impact on soybean plants.
2. Two key visual cues that scream "SDS!" and how to differentiate it from other diseases.
3. Effective management strategies, from crop rotation to variety selection and seed treatments.
4. Why ILEVO^® seed treatment stands out as a champion against both SDS and its well-known accomplice, the soybean cyst nematode (SCN).

Take back control and protect your soybean fields from the silent thief. Dive into this guide and unlock the secrets to a healthy, high-yielding harvest!

📸: BASF internal photograph/Featuring sudden death syndrome on April planted soybean leaves.

Soybean's Silent Thief: Demystifying Sudden Death Syndrome (SDS)

This disease is caused by a soil-borne fungus (Fusarium virguliforme) that infects the roots of young soybean plants early in the season. Rot rot continues throughout the season, reducing yield potential. Visual symptoms are not apparent until later in the season, when toxins from the lower infection are transported up into the leaves. Upper soybean leaves turn yellow or brown with a distinctive interveinal chlorosis. Leaves may drop later in the summer, and the inoculum will survive in the crop residue and soil.

1. SDS life cycle. Sudden death syndrome (SDS) was first confirmed in Arkansas soybean fields in 1971 and is now common across most soybean-producing areas. It is considered the second most detrimental disease in soybean production, with soybean cyst nematode being the number one yield robber. 
2. SDS Identification. Two key visual symptoms of SDS are the blue fungal mold on the tap root and the interveinal chlorosis of the upper leaves. Interveinal chlorosis is caused by both SDS and brown stem rot (BSR), but these diseases can be distinguished from each other in the field, as when splitting the stem, the pith is normally unaffected with SDS, while the pith is reddish brown with BSR.

📸: BASF Contributing Writer/Featuring SDS foliar symptoms (Left); and SDS root symptoms (Right).

SDS management

1. Crop Rotation: The SDS fungus can survive many years in the soil without the host soybean plant, so crop rotation is not effective.
2. Cultural Management: Avoiding early planting in cold soils, compacted soils, and soils with drainage problems will help to reduce SDS infection. Many times, SDS is first spotted in the field entrance area, where compaction and drainage are compromised.
3. Variety selection: Varying levels of genetic resistance are available in today’s varieties and involve both root resistance to infection as well as foliar resistance to toxins. Since there is an interaction between SCN and SDS, make sure that when you select an SDS-resistant variety, it also has an effective source of SCN resistance. If the PI 88878 source of SCN resistance is failing, use a Peking variety.
4. Seed treatments: While foliar fungicides are not effective on SDS, some seed or soil treatments do help to reduce SDS severity. As with variety selection, since SDS is usually worse in fields with SCN, it is important to use a seed treatment with activity on both.  

ILEVO® seed treatment is the only proven product that has good activity on both SDS and SCN. In company performance trials over the last 11 years, soybeans have shown a yield gain of 4.3 bu under SDS pressure and a yield gain of 1.7 bu under SCN pressure with compared to a standard.

📸: BASF internal photograph/Featuring 2011-2020 SDS and SCN field performance pressures using ILEVO® seed treatment.

Other seed treatment options have SDS activity, but only ILEVO® seed treatment has good activity on both SDS and SCN.

📸: BASF internal photograph/Featuring a graph showing ILEVO® seed treatment protection against SDS (Left); and effective protection against SCN (Right).

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This content is being brought to you in partnership with Grow Smart Live and contributing authors. BASF provides the information in this article as a service to its customers; however, the views expressed by guest writers are their own and do not necessarily reflect the views of BASF.