KWS

Powdery mildew

Causal agent: Erysiphe betae
Symptoms: First radiating grey mats of hyphae appear. The leaves are covered with a dusty-white or whitish mycelium, mainly on the upper leaf surface. With severe infection the leaves become pale green, yellow later and die.
Epidemiology: Optimum temperature: 25-30 C, relative humidity below 50 %. Mycelium growth is favoured by dry and warm weather with a low relative humidity and heavy dews.
Economic importance: Disease development occurs in all sugar beet growing areas. Losses are incurred from the time of initial infection until harvest. The losses are dependent on the percentage of plants infected and weather conditions.
Control: Chemical active ingredients are available, most active ingredients belong to the chemical group of the triazoles. Applications of sulphur or proprietary brands of fungicides prevent the spread of the disease, which is often accompanied by other leaf diseases. Some varieties have a good resistance to powdery mildew.

KWS