Bacterial Soft Rot of Brassicas, Celery and Potato

Potato Blackleg

Potato Stem Soft Rot

Erwinia carotovora pv. carotovora

plus Erwinia carotovora pv. atroseptica in Potato.


Often slimy and foul smelling bacterial disease with no furry growth or hyphae.

On Potatoes depressed, soft areas appear around the lenticels. They may rot in storage. In the field the stem turns black initially ground level then may proceed rapidly up the stem. The leaves may be rolled and yellow and the plant stiff and easy to pull from the soil. Underground, the seed tuber and stems rot.

On Arum or Calla Lilies it appears as water soaked areas at the base of flower and leaf stalks and the flowers or leaves soon fall over.

On Sweet Corn the stem just above ground level turns dark brown, slimy and eventually collapses.

Carrots infected at harvest may rot in storage especially if kept humid in plastic bags.

Species Affected:

Brassicas, Carrots, Celery, Lettuce, Potatoes, Sweet Corn. Sebago Potatoes appear more susceptible than other varieties.

Arum Lily, Calla Lily, Dahlia, Iris.

Attack a wide range of succulent species.


A common inhabitant of the soil and plant surfaces.

Favoured by damp conditions and where the plant has been damage by insects, disease or mechanical injury.

Life Cycle:

Origin and History:



Management and Control:

Avoid physical damage to crop.

Avoid harvesting in wet conditions.

Destroy crop residues immediately after harvest.

Avoid close rotations between susceptible crops.

Don't over water plants.


Store Carrots in cool, well-ventilated areas.

Avoid harvesting when soil is wet.


Use healthy seed potatoes. Use whole potatoes rather than cut ones for seed.

Avoid planting into wet soils.

Avoid watering until shoots have emerged above ground.

Handle seed Potatoes carefully to avoid physical damage.

Store seed Potatoes in cool, well-ventilated conditions.

Discard unhealthy seed Potatoes.

Avoid harvesting when soil is wet.

Don't plant Potatoes in infected fields for 12 months.

Related and Similar Species:




Collated by HerbiGuide. Phone 08 98444064 for more information.