Sugar Beet Diseases: Cercospora Leaf Spot

Abstract

Sugar beet (Beta vulgaris L.) was first commercially processed in 1802 in Cunern, now Germany, and since that time has become a provider of 25 % of the world’s sucrose requirement. Cercospora beticola causes Cercospora leaf spot which is one of the most damaging foliar fungal pathogens of sugar beet especially in warm and humid growing areas. Crop rotation, incorporation of infected plant debris, use of partially resistant varieties, and timely application of fungicides are combined to manage C. beticola. Fungicides are critical for disease control in areas where the pathogen is endemic. Most classes of fungicides have been used to control C. beticola; however, prolonged use and sometimes overuse have resulted in the pathogen developing resistance and rendering the fungicide ineffective in the field. In Minnesota and North Dakota, the United States, the use of different modes of action in a rotation program and/or fungicide mixtures comprising different modes of action in rotation always with different chemistries has contributed to successful control of the disease over the past 15 years, a reduction in the number of fungicide applications, and savings in fungicide use of $14 million annually compared to the last epidemic in 1998.