An overview of the Sclerotinia sclerotiorum pathosystem in soybean: impact, fungal biology, and current management strategies

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, is one of the most important diseases of soybean. Disease management is complicated by the long-term survival of sclerotia in the soil and the absence of resistance in elite, commercial cultivars. Furthermore, the lifecycle of S. sclerotiorum in soybean fields is highly dependent on weather conditions, leading to a highly sporadic occurrence of the disease over seasons and an aggregated distribution within fields. Management relies on a multi-pronged approach of combining partially resistant cultivars with cultural practices, such as altering row spacing and planting population, along with chemical control. These control measures are constrained by economic trade-offs, incomplete efficacy of chemicals, and a lack of understanding of application timing for fungicides. Newer tools have been developed to improve management, such as disease prediction models that can assist farmers in making decisions about fungicide application. This review aims to introduce the Sclerotinia pathosystem in soybean, while covering the complicated biology of S. sclerotiorum that leads to the need for integrated management by soybean farmers.