Sclerotinia Stem Rot: Over the past week, we have continued to receive numerous questions regarding Sclerotinia stem rot (aka, white mold) and the control of this disease using foliar fungicides. In most soybean fields, we are at the R4 growth stage, or full pod. Fungicides are not recommended at this time for managing white mold. The key point to always remember is that infection by the pathogen that causes Sclerotina stem rot occurred during the flowering period. Sclerotinia stem rot is a monocyclic disease. This means there is only a primary cycle for infection. There is no secondary spread of the disease; although plants that are adjacent or touching an infected plant may become diseased.
Figure 1. Images showing symptoms of Brown stem rot (top) and Sudden death syndrome (bottom).