Halo Blight of Oats

Pseudomonas syringae pv. coronafaciens


Light green, water soaked spots, up to 1 cm diameter, appear initially and enlarge to oval spots with a yellow centre and a yellow green halo. As the disease progresses, the spots merge into brown irregularly shaped blotches. The leaves may wither and die, starting from the tip.

Species Affected:



Survives on crop residues and seed.
Spread by raindrop splash, direct contact and aphids or other insects.
Moist weather favours disease spread and warm dry weather stops spread.

Life Cycle:

Origin and History:



Management and Control:

Plant resistant varieties. See Disease Susceptibility of Oat Varieties.
Plant clean seed.
Avoid planting into Oat stubble.
Burn, bury or graze Oat stubbles.

Related and Similar Species:


(Wallwork, 1992)


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