Sudden death syndrome can develop in soybean fields that remain saturated after a rain event, have poor drainage or experience compaction problems that prevent drainage.
Infections can occur at any time from planting through the reproductive phases, and cool temperatures and high moisture conditions favor disease development, reports Anne Dorrance, Ohio State University.
"SDS is often found in areas of fields with the greatest compaction," she says. "Any factor that keeps the soil moist for an extended period of time can lead to the development of sudden death syndrome," says Dorrance. "But the biggest factor tied to the disease is soybean cyst nematode."
The presence of soybean cyst nematode, which has been documented in nearly every Ohio county, favors the expression of the disease, according to Dorrance. "When the two are together, symptoms and disease severity tend to be much stronger," says Dorrance.
"Growers can help manage the disease by improving soil drainage in their fields. Soybean varieties also exist that show resistance to SDS. Good cultural practices are important in managing SDS," says Dorrance, re-emphasizing the need to control for soybean cyst nematode.
"I've said it before and I'll say it again, the best way to manage soybean cyst nematode is crop rotation, crop rotation, crop rotation," she said. "And also plant resistant varieties. Soybean cyst nematode can be present in a field without SDS, but we are using SDS as a bio-indicator for the presence of cyst populations."
Though researchers have yet to determine the association between SDS and SCN, one theory is that cyst feeding on the plant roots weakens the plant and creates wounds from which the fungus can enter. Dorrance recommends that growers choose varieties that are resistant to sudden death syndrome. In addition, managing soybean cyst nematode is the best way to manage the disease.
"Anything you can do to manage SCN will also help to manage SDS."
The soil-borne pathogen that causes sudden death syndrome, Fusarium virguliforme, produces a toxin that generates the yellow and brown necrosis spots found on the plant leaves.
Dorrance calls sudden death syndrome the "truck-stopping disease" because its symptoms, generally found on plants along field edges or near ditches, are easily seen from the road causing soybean producers to stop and take a look.