Soybean Sudden Death Syndrome
This is Dr. Nathan Mueller, your local agronomist with Nebraska Extension for Dodge and Washington Counties. As you begin to prepare for soybean planting, there is a newer soybean seed treatment option for controlling sudden death syndrome.
Sudden death syndrome or SDS is caused by a soil borne fungus and was first observed in eastern Nebraska in 2004. While this is a relatively new disease for Nebraska soybean farmers, there are several locations in the state where significant percentages of fields are being affected, including in Dodge County. The disease is favored in high-yield environments and is more prevalent during cool, wet growing seasons. Fields that have soybean cyst nematodes have a greater likelihood of having more severe SDS.
In the past, seed treatments have not been effective in controlling SDS, limiting the options for farmers managing this disease. Soybean growers were encouraged to make management adjustments such as selecting varieties with moderate-to-high levels of resistance to SDS and to avoid early planting in fields which are known to be severely affected by SDS. However, previous research has shown that for each delayed day in planting after May 1, 0.25 to 0.625 bu/ac of yield can be lost, making delayed planting a less than optimal management practice.
In 2015, I worked with two of the three farmers participating in the Nebraska On-Farm Research Network to evaluate ILeVO®, a Bayer Crop Science seed treatment. While this product has shown promise for addressing SDS, there are not clear guidelines to determine at what point a field will see enough response to ILeVO® to justify treatment.
Soybean varieties with good resistance to SDS were selected for this study. The farmers in this study were also encouraged to not delay planting if possible, however wet weather proved challenging. The study locations were sampled for SCN to establish the base infestation level for the trial. There was a significant yield increase for the ILeVO® treatment as compared to the standard seed treatment at the Ulysses and Hooper sites (Ulysses had 2 bu/ac yield increase. Hooper had 9 bu/ac yield increase). The Scribner site which had a very low disease index and low SCN numbers did not see a yield response to the ILeVO treatment.
Because SDS occurs in pockets throughout a field it is difficult to establish a disease threshold of when to use ILeVO in order to justify added costs. For this reason, The Nebraska On-Farm Research Network will be continuing this study in 2016. We are currently looking for 3 locations with have a history of sudden death syndrome. If you are interested in participating, call me at 727-2775 or visit our local website at croptechcafe.org. Know your crop, know your tech, know your bottom line. This is Dr. Nathan Mueller, your local agronomist with Nebraska Extension on KTIC radio.