Cercospora leaf spot is the most common disease of beets in New York. Several varieties have been developed with resistance. Resistant varieties have been shown to be an important, effective management practice, but variable in ability to suppress the disease.
In an experiment conducted in SC in 2021 (PDMR 16:V072), leaf spot severity on the resistant variety Bull’s Blood was consistently lower than on all other cultivars tested in both the inoculated section of plots and adjacent section receiving splashed-dispersed spores as the disease developed. Severity was lower on Ruby Queen, a moderately susceptible cultivar, Touchstone Gold, and Vulture, two cultivars with intermediate resistance, than on Chiogga Guardsmark. Cylindra generally was as susceptible as Chiogga Guardsmark. Bull’s Blood had a greater percentage of healthy leaves than all other cultivars, and Ruby Queen had a greater percentage of healthy leaves than the other four cultivars.
In an experiment conducted in FL in fall 2012 (PDMR 7:V080), the golden beet variety Touchstone Gold exhibited the highest level of resistance, remaining almost free of symptoms throughout the experiment. Bull’s Blood, a red-leafed variety, performed next best, followed by Early Wonder, Kestrel, and Red Ace. Detroit Dark Red was rated significantly more susceptible than all of these. Cylindra and Ruby Queen were the most severely affected.
In an experiment conducted in FL in spring 2013 (PDMR 7:V145), Touchstone Gold again demonstrated the highest level of resistance remaining almost free of symptoms. Bull’s Blood again performed next best, followed by Kestrel. Jacob’s Egyptian was moderate in its resistance to leaf spot, while Cylindra, Ruby Queen and Detroit Dark Red were rated significantly more susceptible. Early Wonder was the most severely affected variety in this experiment.
All varieties in these 3 experiments are described as being resistant to Cercospora leaf spot except Chiogga Guardsmark, Early Wonder, Ruby Queen, and Vulture. Information was not found for Jacob’s Egyptian.
Resistant varieties are recommended used in an integrated program with other management practices. Use clean seed, rotate where beets are planted, manage related Chenopodium weeds, apply fungicides, and incorporate crop debris as soon as possible after harvest. Conventional fungicides to alternate among include strobilurins (FRAC Code 11) Quadris and Cabrio, and DMI fungicides (3) PropiMax and Tilt. DoubleNickel is an organic biopesticide that has been documented effective in several evaluations, including in upstate NY; it was applied with the copper fungicide Cueva in these evaluations.
The beet resistant varieties list has additional varieties listed in seed catalogues as being resistant to Cercospora leaf spot.
PDMR stands for Plant Disease Management Reports.
Please Note: The specific directions on fungicide labels must be adhered to — they supersede these recommendations, if there is a conflict. Check labels for use restrictions. Any reference to commercial products, trade or brand names is for information only; no endorsement is intended.
More information/prepared by:
Margaret Tuttle McGrath
Associate Professor
Long Island Horticultural Research and Extension Center (LIHREC)
Plant Pathology and Plant-Microbe Biology Section
School of Integrative Plant Science
College of Agriculture and Life Sciences
Cornell University
mtm3@cornell.edu
May 2022