Integrating Seeding Rates and Pesticide Programs for Managing Sclerotinia Stem Rot in Glycine max with Nitrogen Fertilizer Applications

Abstract

Soybean production in the Upper Midwest region of the United States is consistently limited by the disease Sclerotinia stem rot (SSR). To control SSR, multiple management practices have been studied and implemented to reduce SSR development and preserve yield. This study examined the effects of integrating soybean seeding rates and pesticide programs under nitrogen fertilizer applications in the form of urea (46-0-0) that may occur due to management of other crops, such as corn. From 10 site-years between 2020 and 2021, low seeding rates decreased SSR development while also decreasing yields and partial profits. The effect of pesticide applications on SSR development was influenced by both seeding rates and nitrogen applications. Consistently, applications of the fungicide Endura reduced SSR to the lowest levels while also maintaining the highest yields and partial profits. Soybeans grown with nitrogen applications experienced increased SSR development and decreased yields and partial profits. Overall, this work suggests that using low seeding rates and fungicides improves the management of SSR, and using nitrogen fertilizer applications can result in greater SSR development and decreased economic returns, especially in fields with a history of SSR.