Broccoli and cauliflower growers are being asked to inspect their cauliflower and broccoli crops, following the detection of a new strain of the fungus White Blister Rust.

The Western Australia Department of Agriculture has been collecting samples and confirmed the new strain at properties in Bindoon, Bullsbrook, Guilderton, Munster, Myalup and Wanneroo. Crop surveys are continuing in other broccoli and cauliflower production areas.

Department research officer Rachel Lancaster said White Blister Rust is common in Western Australia, but the new strain affecting cauliflower and broccoli has not previously been detected.

"The Department undertook an awareness campaign at the beginning of the year following an interstate detection of the new strain" Ms Lancaster said.

"Two growers have contacted the Department with broccoli crop, which tested positive for White Blister Rust, which is caused by the fungus Albugo candida," she said.

"The fungus causes yellow-brown spots on the upper surface of leaves and small, raised white blisters up to two millimetres in diameter on the underside of leaves. In infected broccoli crops, White Blister Rust can be readily seen on heads. Swellings may also be found on roots, stems and flowers. The swellings and pustules contain masses of white dusty spores."

The spores can then spread by wind, rain, and irrigation and on insects. The spores can occur on cultivated plants, volunteer plants or weeds like shepherd’s purse. The pathogen can also be carried to new locations on infected produce, farm machinery, seedlings and seeds. Old crop residues can also be a source of new infection for subsequent crops.

Ms Lancaster said registration permits are being sought at a national level for a range of fungicides to manage the disease. Currently, there are no registered fungicides to manage the disease.

She said other options recommended interstate include controlled watering to reduce residual moisture on plants and limit the germination of spores as well as improving airflow around plants such as planting crop rows in the direction of the wind and increasing plant spacing.

Vegetable Growers Association spokesperson Jim Turley encouraged all growers to check their crops and also ensure they adopt on-farm biosecurity measures.

"Potential sources of spores, crucifer weeds and if possible crop debris, should be removed and destroyed," Mr Turley said.

"Any machinery brought onto the property from other places where broccoli and cauliflower are grown should be washed down and visitors should also ensure their shoes and clothing are free of soil and plant material prior to entering a property. " he said.

The Department is working to determine the extent of the spread. Anyone who suspects they have seen White Blister Rust on broccoli and cauliflower crops should contact the Department on 9368 3263.