Powdery mildew

White to grayish, powdery spots on leaves, stems and ears, although the upper surfaces of the leaf surface are most frequently infected. White ‘pustules’ appear as small, white patches, producing masses of spores. Towards the end of the season black spore cases – cleistothecia - can be found embedded in the mildew pustules. The Powdery mildew disease grows well in environments with high humidity and moderate temperatures.

What are the economic consequences of powdery mildew?

Powdery mildew can significantly reduce yields of agricultural, vegetable and fruit crops. Wheat, barley, rye and triticale are grown on more than 44 million ha in the EU. Powdery mildew is a key fungal disease in these crops, causing losses of up to 45%.

How can powdery mildew be controlled?

Powdery mildew in cereals can be controlled by combining best practices of integrated pest management like crop rotation, use of resistant cultivars, removal of debris, reduced use of nitrogen, optimal sowing conditions and timing, and application of fungicides guided by the use of weather-based decision support systems.
More information about the specific control of powdery mildew is given on the Eurowheat website go to ‘Wheat IPM’, ‘Cultural practice and diseases’, Section ‘Non chemical-control of wheat diseases’, click ‘powdery mildew’.

Use of pesticides

Currently, powdery mildew in cereals is frequently controlled with single or multiple applications of specific mildew or broad-spectrum fungicides across Europe. The pathogen has currently developed resistance to a range of fungicides.
Especially changes in sensitivity to azole-based chemicals and the further availability of these fungicides are a majort concern in view of the dependency on these fungicides on a huge acreage of cereals.

BIOCOMES biological control agent

There is a strong need for biological control products as alternatives for powdery mildew fungicides in cereals. No biological control agent (BCA) is currently registered for control of powdery mildew in cereals in the EU.
The new biological control agent may also be effective against other powdery mildew species in other crops or other foliar diseases in cereals.

View slideshare presentation about powdery mildew.