Cercospora is a serious leaf fungal disease
It thrives in warm and humid climates. Optimal conditions for spread and infection are 15–35°C. The most important factor for an infection to occur is that the leaves are moist. The primary spread of infection occurs via spores that are carried by the wind. However, spread can also occur when plant residues are left in the field and can become a source of infection the following year.
Seed-borne transmission has been confirmed, but plays a minor role in commercial cultivation. Other minor routes of spread are rain splash, insects, machinery, and people.
The disease is caused by Cercospora beticola, and the primary host plant is sugar beets. However, it can also infect beets, fodder beets, chard, and spinach, as well as certain weed species, e.g. fat hen, amaranth, and wild mustard. These plants can therefore also be a source of infection.
Most often, symptoms begin to appear at the end of July, and it is important that control measures are started as soon as possible after infection has been confirmed. In severe attacks, yield losses of up to 40% can occur.
At NBR, we conduct inoculated Cercospora trials
At NBR, we conduct inoculated Cercospora trials both to evaluate variety tolerance and to evaluate control products against Cercospora. We use inoculated trials, where we add the fungus to the trials, to ensure that we achieve an even and strong infection so that the evaluation is reliable.
During 2025 and the beginning of 2026, NBR has a master’s student working with Cercospora. He followed the development in the field during the summer of 2025 and is working during the winter on method development related to fungicide resistance. Carl-Hugo Jonsson, as he is called, will defend his work during the spring of 2026.
