White mold (Sclerotinia sclerotiorum) is a fungal disease of soybean that has become a more frequent issue over the past 30 years in the Northern U.S. and Canada.
White mold is a disease of high yield potential soybeans – the better the establishment and growth of the crop, the greater the risk of white mold.
White mold is favored by cool and wet weather and dense soybean canopies that help retain these conditions under the crop canopy.
Integrating several cultural practices is the most effective means of managing white mold. Cultural practices include variety selection, crop rotation, weed management, no-till, and if necessary, limiting dense canopy formation.
Several fungicides are labeled for white mold but must be applied before the appearance of symptoms and generally will not provide complete control.
Foliar chemical applications should be targeted at early flowering (R1); penetration of spray to the lower soybean canopy is necessary for treatments to be effective.