Diagnosing crown rot of cereals

A fungal disease most common in continuous cereal crops, which affects roots and lower stems and is usually not detected until after heading. Significant yield losses can occur when high disease levels coincide with moisture stress during grain fill.

What to look for

Paddock

White heads scattered throughout crop but not in distinct patches (as with take-all).

Plant

Scattered single tillers and white heads.
In severe cases whole plants develop white heads after flowering.
Tiller bases honey-brown colour especially under leaf sheaths.
Pink discolouration often forms around or in the crown or under leaf sheaths - with pink colour becoming very evident on infected plants left in a damp plastic bag for several days.
Affected heads have shrivelled or no grain.

Where did it come from?

Contaminated stubble

Continuous wheat

Crown rot can persist in infected crop residues for up to two years and be carried over in infected grass weeds.
Crown rot is more common when susceptible crops (cereals) are grown sequentially or after long-term grass pastures.

Management strategies

Rotation

Grass weed control

Resistant varieties

Rotate cereals with non-susceptible crops such as pulses, oilseed, lupin or grass-free pasture.
Seed between rows the following season to reduce disease load.
Good grass weed control.
Most wheat varieties grown in Western Australia (WA) are either susceptible or very susceptible to crown rot.

How can it be monitored?

Soil test

Use Predicta B to monitor soil disease levels.

Further information

GRDC crown rot Tips and Tactics for the western region [1]

YouTube: Reducing losses from crown rot - Crop Updates presentation 2015 [2]

Crown rot in Australian winter cereals [3]

PreDicta B testing - provided by South Australian Research and Development Institute [4]