Powdery Mildew - Beet

Erysiphe betae

Powdery mildew (Erysiphe betae) is commonly seen in New Zealand beet crops as greyish-white mycelium on leaves. Favoured by hot weather, severe attacks can significantly reduce yields and feed value of fodder beet crops.

Main Host

Fodder and sugar beet.

Symptoms

Powdery mildew first appears as small surface patches of white, fluffy mycelium. The first symptoms are usually found on the underside of older leaves but it can rapidly spread so that the entire plant appears greyish-white.

Life Cycle

To overwinter, powdery mildew must have living beet material (fodder beet, sugar beet, spinach, swiss chard etc.) to survive. In the spring, wind borne spores are responsible for the infection of new crops with periods of humidity and temperatures of around 25ºC being ideal.

Weather Conditions

Hot, humid conditions, but without moisture present on the leaves are optimum for disease development.

Economic Impact

Severe attacks can significantly reduce the yield and feed value of fodder beet. Overseas, sugar beet yield losses of up to 35% have been recorded.

Control

Escolta has a label claim for the control of powdery mildew.

Powdery mildew beet infection — Powdery mildew infection

Related Pests

Beet Rust

Uromyces beticola

Favoured in cool and wet seasons, Beet rust (Uromyces beticola) is commonly seen in beet crops. Characteristic symptoms are raised red pustules on leaves. Severe infestations can lead to leaf loss and reduce yields.

Cercospora

Cercospora beticola

Favoured by wet and humid seasons, Cercospora leaf spot (Cercospora beticola) is the most economically damaging disease of beet crops. Epidemics can cause the complete loss of crop leaves and dramatically reduce yields.

Ramularia Leaf Spot - Beet

Ramularia beticola

Severe infestations of Ramularia leaf spot (Ramularia beticola) can cause significant defoliation in beet crops. It is first seen as light brown angular spots with dark-brown to reddish margins. Infected leaves turn yellow and die.