Powdery mildew

Powdery mildew is a fungal disease that affects a wide range of plants. The fungus Blumeria graminis is causing powdery mildew in cereals.

What are the symptoms of 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.

Photo: Powdery mildew on a wheat leaf. Picture: Shutterstock

Jürgen Köhl
Jürgen Köhl
Powdery mildew in cereals

Biological Control Agents

At the end of the project a fungal biological control agent for powdery mildew spray applications in cereals will be ready for registration.

Read more

Current stage of the Biological Control Agent


Month 18: Collection of isolates with perspective for BCA development
Month 36: Collection of effective isolates suitable for mass production
Month 36: Results of small-scale field experiments and/or different formulations
Month 48: Field-tested formulated BCA ready for registration


Want to know more about this project? Feel free to contact us!

Contact us

Subscribe to our newsletter

The BIOCOMES project has come to an end. The last newsletter has been sent.


Four years of public-private cooperation results in successful development of new biological control products

The EU project BIOCOMES started at the end of 2013 and aimed at the development of new biological control products. Now, at the end of the project, two new biological control products are...

Read more

“The end of BIOCOMES marks a good start”

“’The results of four years of BIOCOMES have been better than expected,” says project coordinator Jürgen Köhl of Wageningen University and Research. “This partnership between 14...

Read more


Biological control using invertebrates and microorganisms: plenty of new opportunities

In augmentative biological control (ABC), invertebrate and microbial organisms are seasonally released in large numbers to reduce pests. Today it is applied on more than 30 million ha worldwide....

Read more

Have biopesticides come of age?

Biopesticides based on living microbes and their bioactive compounds have been researched and promoted as replacements for synthetic pesticides for many years. However, lack of efficacy,...

Read more

View all publications

Share this