PestFacts WA

Latest blackleg sporacle forecast is predicting high blackleg risk in southern areas

Circular to irregular blackleg lesions on a young canola leaf.
Circular to irregular blackleg lesions on a young canola leaf.  Photo courtesy of: Ravjit Khangura (DPIRD).

The department’s latest blackleg forecast, which is current to 5 June 2018, is predicting that the risk of blackleg is currently high in most of the southern region canola crops.

The model is currently predicting that major spore releases are likely to coincide with canola seedling establishment for the districts of; Esperance Downs, Scaddan, Munglinup, Jerramungup, Mount Barker, Darkan, Katanning, Narrogin and Williams.

Blackleg spores are already releasing in Mount Barker and Esperance Downs.

Canola pathologist Ravjit Khangura (DPIRD) encourages growers in these areas to assess the risk of blackleg in their current canola crop based upon the resistant rating of their planted variety, distance to previous year’s canola residues and whether they have applied an upfront fungicide application.

Ravjit says seasonal conditions have been unique this season and due to the late break most of the dry sown crops will be emerging now. Consequently, these crops are at a high risk of intercepting the spore showers at the seedling susceptible stage of the crop. Unprotected crops in medium to high risk situations are likely to be benefited from foliar fungicide application.

In some central and eastern districts (such as Moora, Lake Grace and Lake King) the risk of blackleg is currently predicted to be medium. Whereas, in some far northern, central and eastern areas (including Eradu, Mullewa, Wongan Hills and Merredin), the current risk of blackleg is predicted to be low.

Please visit the department’s Canola blackleg spore maturity forecast for Western Australia to find out for the forecast for other districts.

The blackleg spore shower risk will change each week as the season progresses depending upon the weather conditions in the coming weeks, therefore, growers are urged to check the weekly updates.

The recently released BlacklegCM app can be downloaded onto tablets from the apple store or Google Play and used to support decisions on fungicide management options. Developer of the app Art Diggle (DPIRD) says that the app allows the user to enter information specific to their paddocks and circumstances. For more information refer to the department's BlacklegCM page.

For further details on blackleg management and current blackleg ratings refer to GRDC’s Blackleg Management Guide (2018 autumn variety ratings).

For more information about blackleg in canola and the blackleg sporacle model contact Ravjit Khangura, Research Officer, South Perth on +61 (0)8 9368 3374 or Kawsar Salam, Research Officer, South Perth on +61 (0)8 9368 3104.