When it comes to diseases of Swiss chard, one stands out above all others: Cercospora beticola, or Cercospera leaf spot. If you grow Swiss chard or beetroot, you are more than likely to have encountered it.
TRIGGERED BY MOISTURE
The pathogen becomes active under warm, wet conditions and periods of high humidity. Frequent dew, for leaf spot in the summer rainfall areas due to the many prolonged wet periods.
