Thanks for checking out our “Ask the Agronomist” feature! Here, we’re answering some questions we’ve been getting about Sudden Death Syndrome.
Q: We’ve received a question from a farmer this week saying “Sudden Death Syndrome is breaking bad in my soybean fields. Why does it appear to be affecting more fields this year and what can I do about it?”
A: Sudden Death Syndrome appears after flowering in the growing season, and usually we see issues in early August. Cool, wet planting conditions, like what the Upper Midwest experienced earlier this year, can increase severity of sudden death later on in crop development.
Q: What symptoms should we be looking for?
A: Farmers should first be scouting for yellow blotches on leaves. These will progress into larger patches, but keep in mind that leaf veins remain green while the rest of the leaf will eventually turn brown and leaflets will fall off. However, petioles will remain on the stem. SDS can cause rotted root systems, too.
Q: Are there certain soil types or fields more prone to SDS?
A: There isn’t a certain type of soil that is more prone, but there are specific areas of a field that can more easily develop SDS. High moisture areas such as low spots can have higher severity, and it is also often correlated with compacted soils in margins of a field or low-lying bottoms.
Fields with a history of SDS should be planted when soils are warmer and drier. No-till practices allow soils to remain cooler and wetter during the spring, so these fields are more at risk as well. Sometimes, tillage on a field with a history of SDS is a good practice as long as those fields aren’t worked in wet conditions.
Q: What can farmers do if they begin to notice SDS in their fields this year?
A: Unfortunately, there is not much that can be done to stop SDS once it begins. Prevention is the best defense against SDS. Prevention tactics include: responsible tillage practices to reduce soil compaction, waiting for soils to dry up towards the end of planting seasons, and testing for presence of soybean cyst nematodes. Soybean Cyst Nematodes (SCN) are associated with SDS.
Q: What can be done if farmers test their soils and find a soybean cyst nematode presence?
A: The best way to combat SCN is to plant resistant varieties, or avoid susceptible varieties. Be sure to keep Latham IRONCLAD™ soybeans in mind when mapping out which varieties will be used on different fields.
To bear the IRONCLAD™ name, each soybean variety must be SCN resistant, phytophthora root rot resistant, and an iron deficiency chlorosis rating of 2.2 or better. Depending on the geographic location needs, IRONCLAD™ varieties must protect against either white mold or SDS with a rating of 2.2 or higher.
Q: If there is no cure for SDS, why should farmers be scouting for it?
A: An ounce of prevention is worth a pound of cure. Scouting for SDS is important to determine if management practices were at fault and to help select the right seed for each field next year based on SDS score and Soybean Cyst Nematode tolerance.
Walking fields and taking notes will help farmers determine an action plan for next year. What we’re seeing now in the fields can have an impact on what we see in the future.