Webinar will provide timely advice on blackleg

Date: 23 Mar 2021

image of blackleg on canola leaf
Blackleg lesions on a canola leaf. Photo: ©Gavin McDouall.

Grain growers and advisers are encouraged to register their participation in a national webinar in which experts will provide the latest information on managing blackleg, one of the most serious diseases of canola.

The ‘BlacklegCM’ webinar, on March 31, will also discuss how to increase the probability of an economic return from fungicide application by using the BlacklegCM App – a tool designed to help determine the best and most profitable management strategy to reduce blackleg disease and increase profits.

This event has been organised as part of a Grains Research and Development Corporation (GRDC) investment that aims to deliver disease management tools and targeted risk information to Australian growers.

Experts Steve Marcroft, of Marcroft Pathology and Department of Primary Industries and Regional Development (DPIRD) principal research scientist Art Diggle will host the webinar.

Project leader, DPIRD senior research scientist Jean Galloway, said the webinar would update growers and advisers about blackleg, caused by the fungus Leptosphaeria maculans, and highlight the different management strategies for traditional and early sowing times.

“It will also be a timely opportunity to remind participants about the BlacklegCM app, which enables the user to compare the likely economic outcome of various strategies applicable to their own circumstances – such as paddock selection, variety choice, seed dressing, banded fungicide and sprayed fungicide,” she said.

“We plan to guide the audience through the use of the app and instil confidence that it is robust and nationally applicable, having been developed using more than 20 years of national data and expert canola pathology knowledge from Victoria, Western Australia, South Australia and New South Wales.”

Dr Marcroft said he had received many queries recently from growers and advisers seeking advice on what to do in order to best manage blackleg in their own circumstances, particularly around whether to apply foliar fungicides early in the season.

He said if growers were sowing a canola variety highly resistant to blackleg and that had a seed treatment applied, it was likely no economic return would be achieved by applying a fungicide at the four to eight-leaf stage.

“But if you are sowing a more susceptible cultivar right next to last year’s canola stubble, then you really need to do everything you can to protect your crop in a district with a lot of canola,” Dr Marcroft said.

He said the trend towards early sowing of canola crops meant crops were likely to flower early and this in turn meant they were more vulnerable to upper canopy infection from blackleg.

“Nonetheless, sowing early means the severity of the traditional blackleg crown canker is likely to be reduced at earlier growth stages,” Dr Marcroft said.

“This change in the farming system means a seed-dressing may not be required, and it is less likely that there’ll be an economic return from a foliar fungicide application at the four to eight-leaf stage.

“However, monitoring for blackleg upper canopy infection later in the season is recommended, as earlier sowing and the subsequent earlier date to the first flower may result in increased upper canopy infection.”

The BlacklegCM webinar will be on Wednesday, March 31, from 11.30am-12 noon AEST (8.30-9am AWST).

More information on managing blackleg disease is contained in the recent GRDC GroundCover™ article ‘Weigh up canola blackleg risk before sowing’.

Contact details

For interviews

Jean Galloway, DPIRD senior research scientist
08 9690 2172; 0475 959 932

Steve Marcroft, Marcroft Pathology
0409 987 941


Natalie Lee, GRDC Communications Manager – West
0427 189 827

GRDC Project code: DAW1810-007RTX