Testing the efficacy of bicarbonates as fungicides against Cercospora beticola

Authors: BUBLITZ, DANIEL - Michigan State University; Hanson, Linda

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2018
Publication Date: 12/1/2017
Citation: Bublitz, D.M., Hanson, L.E. 2017. Testing the efficacy of bicarbonates as fungicides against Cercospora beticola. Phytopathology. 107:S5.168.

Interpretive Summary:

Technical Abstract: Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is an economically important pathogen of sugar beets in many production areas throughout the world. The application of fungicides has been one of the most effective management tools for CLS, but their effectiveness has diminished due to fungicide resistance. To manage CLS in the future, the development of new fungicides will be critical. One group of chemicals that may be effective against CLS is the bicarbonates, particularly potassium, sodium, and ammonium bicarbonate. Previous studies have shown these chemicals can reduce disease severity with Sphaerotheca fuliginea, Botrytis cinerea, Venturia inaequalis, and other fungal species. To test their efficacy against C. beticola, lima bean agar plates amended with either 70% ethanol as a control or one of the bicarbonates plus 70% ethanol for a final concentration of 1% (ethanol v/v, bicarbonate w/v) were prepared. A plug of C. beticola was transferred to each plate, and the diameter of the fungal colony was periodically measured with a caliper and recorded starting five days after the transfer. After seven days, the plates treated with potassium bicarbonate showed nearly a 50% reduction in growth compared with the ethanol plates. As other fungi vary in sensitivity to the form of bicarbonate, testing of the other forms is ongoing. Based on these findings, it is possible that bicarbonates could be useful to manage C. beticola in the field.