PestFacts WA

Upper canopy infection of blackleg in canola

  • Wongan Hills
Blackleg infection on canola pods
Blackleg infection on canola pods. Photo courtesy of: Stacey Hansch (DPIRD).

Crop production agronomy officer Stacey Hansch (DPIRD) has reported finding blackleg infection on pods of Stingray canola plants in an irrigated trial near Wongan Hills. There was no sign of infection in stems on leaves, just pods. The crop was sown on 20 March and was at the pod ripening stage.

With plants past the seedling stage, basal blackleg control options have expired. Leaf infections are common on varieties with no effective resistance, such as ATR Stingray and ATR Bonito.

Canola flower infected with blackleg
Canola flower infected with blackleg. Photo courtesy of: Andrea Hills (DPIRD).

Excluding leaves, upper canopy blackleg infections (UCI) will occur on varieties that are not rated as moderately resistant to resistant (MR-R) as bare seed, which includes ATR Bonito. UCI can infect all parts of the canola plant including flowers, whole heads (causing head abortion), stems, branches and pods. Note that another disease, alternaria, can also occur on pods and it is easily confused with blackleg. UCI is usually worse in very early sown crops.

In some situations upper canopy infections can cause yield loss but it is seasonally dependent and not easy to predict as trial work has shown that the visible symptoms and losses are not well related. While no fungicides are registered for UCI, growers concerned about these infections can use a fungicide registered for sclerotinia, up to full bloom stage.

More information on managing blackleg and past blackleg reports received this season is available at DPIRD’s;

For more information on blackleg contact plant pathologists Andrea Hills, Esperance on +61 (0)8 9083 1144 or Ravjit Khangura, South Perth on +61 (0)8 9368 3374.


Article authors: Andrea Hills (DPIRD Esperance) and Cindy Webster (DPIRD Narrogin).