Managing White Mold with a Strategic Plan
2022
- Department of Plant Pathology, UW Madison
Project Media
Sclerotinia stem rot (a.k.a. white mold) is a disease of soybean (Glycine max) caused by the fungal pathogen, Sclerotinia sclerotiorum (Roth et al., 2020). In highly conducive years, white mold can cause soybean yield losses of up to 61 million bushels in a single season (Bradley et al., 2021). Sclerotinia sclerotiorum most successfully initiates infections in soybean during flowering periods by releasing puffs of ascospores into the canopy of the crop. These ascospores then germinate and grow on senescing plant tissues such as flowers, leading to infection and colonization of soybean vascular parts. Upon full constriction of the soybean stem by S. sclerotiorum, the infected soybean plants begin to prematurely wilt and die, resulting in reduced seed fill and subsequent yield losses. While yield losses due to white mold can be substantial, a disease severity index (DIX) rating of 40% is needed for significant losses, with severe losses only being found at a DIX of 68% (Willbur et al., 2019). In order to prevent the development of white mold and the resulting yield losses, management practices for controlling this disease have been the focus of many independent research efforts.