Sudden death syndrome is no joke.
This fearsome soybean disease gets its hooks into the plant early, but the interveinal chlorosis symptoms don't show up until much later. When University of Illinois plant pathologist Carl Bradley talks about SDS, he usually lists everything that doesn't work for SDS management.
The disease begins in the plant's roots. Since foliar fungicides are not fully systemic, a rescue treatment will not work. There's just no way to get fungicide to the disease location. Rotation is also ineffective. Bradley notes research has shown that the SDS fungus will survive on corn, wheat and weeds. But, symptoms will not present on these hosts. Tillage may have a slight effect on SDS. But, it falls well short of being considered a viable treatment option.
So, most often Bradley will recommend growers choose a variety with SDS resistance as the best way to guard against the disease. That, and hope weather conditions aren't conducive to SDS propagation. Until 2014, growers hadn't seen a bad SDS year for quite some time, Bradley notes.
Fortunately, there is some good news for those who have bitter memories of SDS-infected fields from last year.
Bayer CropScience has a new product, ILeVO, that puts growers on the offensive. According to Jennifer Riggs, Bayer's SeedGrowth product development manager, ILeVO is a seed treatment that provides a two pronged defense against SDS.
ILeVO features a traditional chemical component with activity on fungi and nematodes. In addition, Riggs notes an SDHI fungicide (fluopyram) provides activity on fungicide and nematodes by inhibiting the respiratory pathways.
"ILeVO works by stopping early season SDS infection," Riggs notes. "It stops the ability of the fungus to infect at the seedling stage."
As the plant grows, the ILeVO treatment moves in from the seed coat and into the plant, Riggs adds. Additionally, Riggs says Bayer has seen a soybean cyst nematode suppression effect with ILeVO. She recommends pairing ILeVO with Poncho/VOTiVO for even more protection against nematodes.
In testing, ILeVO provided a 4- to 10-bushel boost when visual SDS symptoms were present. Riggs notes it made an even bigger difference in fields where SDS incidence and severity were greater. In the worst cases of SDS, Bayer saw yields of 60+ bushels with ILeVO versus 10 bushels on the untreated check.
"With ILeVO, we're not saying it will get rid of SDS," Riggs adds. "But, the symptoms will be less frequent and less severe."
At U of I, Bradley has tested ILeVO for numerous years.
He agrees with Bayer's claim that an average of 4 to 10 bushels should be expected in fields exhibiting SDS symptoms. He evaluated soybean seed with a standard seed treatment versus the same soybean seed with a standard seed treatment plus ILeVO. His trials featured three different soybean varieties with both treatments.
While ILeVO shows promise, Bradley notes it is not a substitute for a resistant variety. He recommends growers pair a variety with SDS resistance with the ILeVO seed treatment for the best protection.
Additionally, Bradley notes he did not test Bayer's claims of SCN suppression with ILeVO. However, he notes several universities (University of Arkansas, University of Wisconsin, and Iowa State University) are currently testing the seed treatment's effect on SCN.
ILeVO will be available this spring for planting. Riggs notes Bayer worked hard over the winter to get the product shipped to local co-ops across the Corn Belt.