Diagnosing abiotic leaf spots in cereals
Scattered leaf spots that have an abiotic cause such as droplet freeze damage, spray solvents or topdressed fertiliser burn.
What to look for
- Plants with white lesions with a rim that may initially be pale then go brown that re uniformly distributed or concentrated in frost-prone areas.
Paddock
- White lesions that are often drop-shaped or span the width of the leaf causing the leaf to kink, or leaf tips to shrivel.
- As the plant grows, lesion position on successive leaves varies reflecting a single occurrence.
- Some leaf sheaths and associated stems areas may be shrivelled or discoloured.
- Some leaves that were emerged at the freeze event can have numerous small interveinal spots.
- Later emerging leaves are unaffected.
Plant
What else could it be
| Condition | Similarities | Differences |
|---|---|---|
| Diagnosing contact herbicide damage in cereals | Similar lesions on the leaf | More extensive coverage |
|
Nutrient deficiency
|
Similar leaf spots | Symptoms progress as the plant grows |
Where did it come from?
- A common cause is frozen water droplets
- Differing lesion shape is caused by individual droplets on leaf surface, under a leaf bend, or in the leaf axil.
- Freeze damage in the axil can damage the enclosing leaf sheath, stem and up to 3 leaves at various stages of emergence.
- As the leaves develop further lesions are found further up later developing leaves.
Further information
Where to go for expert help
Page last updated: Tuesday, 27 September 2016 - 3:06pm