Shaking blackleg

As blackleg is a serious fungal disease of canola worldwide, producing blackleg-resistant varieties is a major focus for canola breeders.

During 2003, CSIRO Plant Industry collaborated with the Victorian Department of Primary Industries in a major survey of commercial canola crops across eastern Australia.

Canola varieties containing blackleg resistance incorporated from a wild relative of canola (sylvestris resistance) were targeted in order to determine if this resistance was breaking down.

The survey looked at 102 paddocks over NSW, Victoria and South Australia and found that blackleg was present in 95 per cent of crops surveyed with the sylvestris resistance. In Victoria and NSW, disease severity was low and most crops did not record yield loss, however blackleg was found in over 90 per cent of crops.

Infection was particularly severe in South Australia, where crop losses of up to 90 per cent were recorded in sylvestris varieties.

In South Australia, where varieties with this resistance have been grown extensively, crop losses in 2003 have been estimated at $20 million.

Researchers are recommending growers sow varieties with polygenic resistance, based on several genes, as these varieties are not affected by the strains of the blackleg fungus able to overcome the sylvestris resistance.

Management strategies, such as keeping crops away from stubble of last years sylvestris varieties, judicial fungicide use and close monitoring of crops, can reduce damage and help maintain blackleg resistance.

For details of susceptible canola varieties and more information on managing blackleg in canola crops, click on the link below. 

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