Biosecurity alert: Dickeya dianthicola

Page last updated: Wednesday, 25 October 2017 - 1:20pm

Please note: This content may be out of date and is currently under review.

Dickeya dianthicola is a serious bacterium that can cause tuber soft rot and blackleg in potatoes, and can also affect some ornamental varieties, chicory and artichoke.

The bacteria was detected in Australia, for the first time, in June 2017 on a Western Australian commercial potato growing property. In addition to seed potatoes, the bacteria has since been found in dahlia tubers and freesia bulbs imported from Victoria.

All potato, vegetable and flower growers, and production nurseries need to be vigilant and report suspect signs to the Plant Pest Hotline on 1800 084 881.

Current situation

The Department of Primary Industries and Regional Development (DPIRD), in conjunction with the Western Australian potato industry, will implement a management strategy for Dickeya dianthicola following a national decision that it cannot be eradicated.

The National Management Group (NMG) decision that the pest is not technically feasible to eradicate is based on the recommendation provided by the Consultative Committee on Emergency Plant Pests.

Quarantine restrictions on five commercial properties in WA have been lifted.

Further tracing activities are being undertaken by Victoria, New South Wales, South Australia and WA, including testing of available potato tubers, dahlia tubers in Victoria and WA, and freesia bulbs from Victoria.

The Potato Growers Association of WA (PGAWA) will lead management efforts to minimise industry impacts. This will include raising grower awareness of buyer responsibility to understand the risks of spread.

DPIRD will provide technical advice, fee for service laboratory testing and will work with PGAWA to modify the Certified Seed Scheme and Registration Rules to manage the disease.

There are currently no additional interstate trade restrictions being considered for potatoes apart from those restrictions in place for the tomato potato psyllid.

The international market access for WA potatoes remains unaffected.

Trade in cut flowers from WA is already subject to interstate movement conditions for other pests.

The Australian Government Department of Agriculture and Water Resources will work with overseas trading partners should any issues arise.

What is Dickeya dianthicola 

Dickeya dianthicola causes soft rot and blackleg in potatoes. It is a serious pest (bacterium) that was not previously known to occur in Australia. Overseas data has indicated significant yield losses in potato crops.

Dickeya dianthicola can also infect other crops, including some ornamentals (including carnation, lily, chrysanthemum, dahlia, begonia, flaming Katy, freesia, hyacinth and iris), globe arichoke and chicory.

Other pathogens already present in Australia can cause similar soft rot and blackleg symptoms. However, Dickeya dianthicola is more aggressive and causes disease at lower infection levels.

This pest is not associated with the Tomato potato psyllid.

Host list

  • Potatoes
  • Globe artichoke
  • Chicory
  • Begonia
  • Calla lily
  • Carnation
  • Chrysanthemum
  • Dahlia
  • Dianthus, Sweet William
  • Freesia
  • Hyacinth
  • Iris
  • Kalanchoe, ‘Flaming Katy’ which is also known as ‘Christmas kalanchoe’, ‘florist kalanchoe’ and ‘Madagascar widow’s thrill’

Farm biosecurity is essential

Dickeya dianthicola has a large potential host range and can persist in the soil for many months. In WA it has moved from dahlia to potato, proving that it can easily transfer between different crops.

A number of hosts may be asymptomatic. Therefore we strongly urge all growers to put in place, or maintain, strict on-farm biosecurity measures. This will help to restrict the spread and impact of this bacteria.

Biosecurity information sheets for Dickeya dianthicola can be downloaded from this website.

You can also get helpful information on the website. Some of the critical measures you can take are:

  • clean equipment, vehicles, machinery and footwear before entering a new crop, paddock, or another property
  • keep unnecessary visitors and vehicles out of your cropping paddocks
  • source your seed and bulbs from reputable suppliers
  • keep accurate records of seeds and plant material coming onto, and leaving your property.

​All potato, vegetable and flower growers as well as production nurseries need to be vigilant for signs of this pest in their crops. If you think your plants may be affected call the Exotic Plant Pest Hotline on 1800 084 881. 

Early reporting is critical in containing the bacterium and can lower the risk of it spreading to more properties. 


Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080