Cercospora Leaf Spot on Sugar Beets
Posted on July 08, 2022
Cercospora leaf spot (CLS) is an airborne fungal disease caused by the organism Cercospora beticola. CLS appears first in lower leaves as individual, circular spots that are tan to light brown with reddish purple borders (University of California Agriculture and Natural Resources).
CONDITIONS FAVORABLE FOR CLS
Environmental conditions play a major role in the occurrence of CLS. Likeliness of infection is favored in warm, humid, and rainy weather. Spores form most readily at temperatures between 68-79°F with relative humidity between 90-100%. Spores do not form when temperatures are below 50°F. CLS is airborne, meaning spores germinate and infect sugar beet leaves through the natural openings on the leaf surface (stomata). Visual symptoms will occur 5 to 21 days after infection and will appear as lesions, first occurring on lower leaves, Figure 1. These spots will move upwards on the plant, infecting new growth as the disease progresses.
Figure 1. Photo Credit: Robert M. Harveson, University of Nebraska Lincoln
YIELD LOSSES AND IMPACT
According to University of Nebraska-Lincoln, yield losses due to this disease can approach 40%. This yield loss is due to the disease’s impact on sugar production and root growth, which impacts overall tonnage at harvest.
MANAGEMENT RECOMMENDATIONS
Create a management plan to combat CLS in fields. This plan may utilize several best management practices including crop rotation, residue management, proper variety selection, and fungicide application(s). Fungicide applications are designed to protect yield and minimize additional yield loss. Piggy-backing foliar fertilizers with fungicide applications is an efficient way to provide nutrients to growing crops to maximize yields. The Andersons High Yield Sugar Beet Solutions program on the next page outlines specific products to apply throughout the season based on your application timing. Generally, The Andersons products are compatible with most spray materials. However, always perform a compatibility (jar) test before mixing.
HIGH YIELD SOLUTIONS
To download the full version of The Andersons High Yield Sugar Beets Solutions visit AndersonsPlantNutrient.com/HighYield.
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