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A guide to powdery mildew management

Powdery Mildew

Recent warm weather has meant crops are beginning to develop out of the winter period, with the lack of severe winter weather across the country mildew populations are still established, especially with the relatively low levels of rainfall earlier in the season

What is powdery mildew?

Powdery mildew is a fungal disease that can affect a wide range crops and can be particularly problematic if left untreated in cereal crops.

There are several different strains of the mildew fungi species blumeria. Graminisf. Sp which are crop specific. Wheat, barley, rye and triticale are susceptible to powdery mildew.

Conditions favouring and promoting powdery mildew

Rising temperatures in the spring following winter, especially if conditions have been dry or there has been snow cover

Germination is promoted at moderate temperatures and during high humidity, 

Powdery mildew spores germinate above 6°C 

Dense crops promote the ideal micro climate for powdery mildew development

High nitrogen applications which promote rapid lush growth

Late drilled wheat crops are particularly at risk during the rapid spring growth phase, 

Over use and/or under dosing with fungicides can lead to insensitive strains of powdery mildew surviving

Impact of powdery mildew

Infection on the leaves reduces the available surface area for effective photosynthesis and subsequently leads to a decline in the available energy the plant can put into growth and reproduction resulting in yield loss.

Earlier infection can produce the largest impact if it is allowed to move up the plant, especially when it infects the flag leaf. Yield loss of up to 20% is possible with high infection levels.

Mildew can be a key disease to control early on in wheat alongside septoria, especially in susceptible varieties. 

Management Approaches

Control volunteer host plants to prevent a green bridge from season to season

Planting more tolerant varieties

Avoid over applying nitrogen

Treating early infections with fungicides should be used as part of an integrated approach and particular attention on application timing, dose rate and alternating modes of action are vital to sustainable control 

Products you may be interested in



A protectant fungicide containing 50 g/litre cyflufenamid, with useful curative activity against powdery mildew on a range of cereal crops.

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A protectant fungicide with useful curative activity against powdery mildew on a range of cereal crops. It contains 50 g/litre cyflufenamid.

See more…

Further Information

logo for AHDB cereals & oilseeds

AHDB Reccomended List 2019

The AHDB reccomended list 2019/20. This contains diseases susceptibilty scores for powdery mildew as well as other diseases. 

AHDB Powdery mildew guide

A comprehensive guide, with further information on powdery mildew from AHDB.

Related Articles

Where active powdery mildew is present in susceptible cereal crops, growers are advised to include a specific mildewicide in T0 fungicide applications for early control.

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