by Kiersten Wise, Soybean Plant Pathologist, Purdue University
For years, zone lines on the interior of soybean stems were considered a diagnostic feature of the disease charcoal rot, caused by the fungus Macrophomina phaseolina
. Recent research has shown, however, that this sign is NOT associated with charcoal rot, but is associated with diseases caused by Diaporthe species of fungi, like those which cause soybean stem canker and pod and stem blight.
This new publication is intended to help dispel the myth that zone lines are associated with charcoal rot, and to help farmers accurately identify the cause of zone lines observed in soybeans.
The publication is part of a three-year research project on charcoal rot, conducted in six mid-western states and funded by the North Central Soybean Research Program. Final results of the project, called Understanding the role of fungicide programs on soybean health and charcoal rot development
, will be posted on this website in the coming weeks.
Read Soybean Stem Zone Lines: Fact and Fiction
Read more about charcoal rot
Read more about soybean stem canker