Evaluation of Fungicide Spray Programs to Manage Cercospora Leaf Spot in a Moderately Susceptible Sugar Beet Variety in Northwest Minnesota, 2025

Cercospora leaf spot (CLS), caused by Cercospora beticola, is the most important foliar diseases of sugar beet in the Red River Valley of Minnesota and North Dakota and Southern Minnesota. CLS symptoms appear as more or less circular spots with tan to brown centers with visible black pseudostromata upon maturation. In this study, we evaluated the efficacy of fungicide spray programs with emphasis on the first and third fungicide application for management of CLS. The trial was conducted at the University of Minnesota, Northwest Research and Outreach Center in Crookston, MN on a moderately tolerant sugar beet variety (Beta vulgaris ‘Crystal 912RR’). Results from this study will help sugar beet growers make informed CLS management decisions with regards to fungicide application.