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
- White heads scattered throughout crop but not in distinct patches (as with take-all).
- 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.
What else could it be
|Diagnosing take-all in cereals||Tiller death and white heads||Crown rot causes the characteristic honey-brown colour rather than the black of take-all|
Frost, copper and molybdenum deficiency
|White heads||Crown rot causes tiller death and honey-brown colour discolouration of stem bases|
Where did it come from?
- 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.
- 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?
- Use Predicta B to monitor soil disease levels.