The cooler than normal weather, all the rain and higher humidity could mean the return of white mold.
White mold, also known as sclerotinia stem rot, is caused by the fungus Sclerotinia sclerotiorum. It appears as fluffy white mycelial growth, most prominently on the stems. White mold is heavily influenced by weather and microclimatic conditions. Progress of the disease is favored by below-average air temperatures, high relative humidity, and soil moisture. When these conditions occur during the two weeks prior to peak flower on the lower stems, the disease incidence can be especially severe.
With higher commodity prices growers have been managing for higher yield levels. Many of the practices associated with these trends— shorter rotations, narrower rows, earlier planting—create a less healthy environment that favors white mold development. At the Iowa State ICMC conference it was suggested to avoid white mold don’t try and grow high yielding soybeans. Thanks for the help!
You could try a variety that is resistant to white mold, but those varieties are usually lower yielding than the susceptible genetics.
If you want high yielding white mold free soybeans, start with the soil. I showed Craig Grau, Professor of Plant Pathology, University of Wisconsin- Madison our research on stopping white mold. He told me that yes gypsum applied before planting is a great preventative to white mold.
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