Worldwide distribution. Damage mostly on older leaves, especially severe on sugar beet, but also on beetroot, silver beet, Amaranthus, spinach, lettuce, weeds. Potential to damage baby-leaf crops.
Leaf spots, round to irregular, 2-5 mm wide, ash-grey to pale brown, usually with brown or reddish-purple borders. Spores develop on the spots; sometimes centres fall out. Spots join together, leaves dry, later collapse, although remain attached to the plant.
Spread by rain-splash and wind. Survival on crop debris in soil, seed, weeds.
Cultural control: certified seed; weed (especially, Chenopodium); collect debris and destroy after harvest; crop rotation.
Chemical control: use mancozeb. Apply when symptoms first appear, repeating at 7-10 intervals.
Beetroot leaf spot
AUTHORS Grahame Jackson & Eric McKenzie Information Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, et al. CSIRO Publishing; and CABI (2017)Cercospora beticola (cercospora leaf spot of beets). Crop Protection Compendium. (https://www.cabi.org/cpc/datasheet/12191); and from (including Photo 1) McKenzie E (2013) Cercospora beticola:PaDIL - (http://www.padil.gov.au).
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.