Vegetable growers encouraged to check for white rot

Western Australia gardeners harvesting vegetables from the onion (allium) family have been urged to report any signs of white rot to the Department of Agriculture and Food, after the fungal disease was found in garlic from a Perth backyard and Swan Valley property.

It is the first time white rot has been found in WA, to which garlic and onions are particularly susceptible, as well as leeks, shallots, chives and ornamental alliums.

Department of Agriculture and Food chief plant biosecurity officer John van Schagen said the cold, damp spring most likely provided suitable conditions for the white rot fungus (Sclerotium cepivorum) to develop to a stage where it was visible to the naked eye.

Mr van Schagen asked vegetable growers to inspect their plots and to report any symptoms to help determine whether or not the disease is widespread.

“Often there are limited above-ground symptoms of white rot disease, such as stunted growth or yellowing and wilted leaves, and the disease is first discovered when harvested,” he said.

“The disease manifests as a fluffy white growth on the plant roots and root plate, with tiny black growths like poppy seeds, which are called sclerotia. In severe cases the bulb will be completely rotten.”

Mr van Schagen encouraged growers to employ good biosecurity measures to prevent the risk of spreading white rot.

“It is important for gardeners to wash any soil from infected parts of the garden off their footwear and tools before moving to other areas of the property,” he said.

“The best way to avoid infection is to purchase plants that are certified as disease free or grow crops from seed.”

While white rot in alliums is new to WA, the disease is widespread in the eastern states and overseas.

There are currently no white rot resistant varieties available, however, the disease can be managed by good sanitation, rotating plantings and use of registered fungicides. For more information on control options refer to DAFWA’s web page agric.wa.gov.au/whiterot.

The department has been working closely with vegetablesWA since the white rot discovery, to provide commercial growers with information and advice about the disease.

Any suspect signs of white rot can be reported to the department’s Pest and Disease Information Service on freecall 1800 084 881 or by emailing info@agric.wa.gov.au

Reports can also be lodged via the department’s MyPestGuide app or online via mypestguide.agric.wa.gov.au

Related article

Biosecurity alert (Department of Agriculture and Food WA)