Iowa soybean acreage has been increasing. So has the percentage of soybean fields found contaminated by the brown stem rot fungus. Here is a description of the symptoms plus suggestions for helping control this disease.
Dunleavy, J. M.
"Brown Stem Rot in Soybeans,"
Iowa Farm Science: Vol. 20
, Article 2.
Available at: https://lib.dr.iastate.edu/farmscience/vol20/iss10/2