Cercospora leaf spot of sugar beet: A review of biology, epidemiology, and management strategies

Abstract

Cercospora leaf spot (CLS), caused by Cercospora beticola, is the most destructive foliar disease of sugar beet (Beta vulgaris L.) worldwide and one of the leading production challenge in the Red River Valley of the United States. Epidemics of CLS result in severe defoliation, root yield losses of up to 40%, and reduced sucrose quality. For decades, CLS management has relied on fungicides, particularly quinone outside inhibitors (QoIs) and demethylation inhibitors (DMIs). However, the intensive use of these single-site fungicides has led to the emergence of resistant C. beticola populations, causing a decline in fungicide efficacy and complicating management decisions. The spread of resistance across major sugar beet-growing regions underscores the urgent need for integrated disease management strategies that combine cultural practices, resistant cultivars, and strategic fungicide use. This review synthesizes current knowledge on the biology, epidemiology, host range, and disease cycle of C. beticola, with particular emphasis on major fungicide resistance mechanisms and their implications for CLS management to provide a comprehensive framework that informs sustainable CLS management and supports the development of effective resistance management programs.