Canola disease ratings revised

Canola disease ratings revised

Cropping
TEST RESULT: Steve Marcroft says results from recent blackleg screenings of canola cultivars have been factored into the updated disease ratings for 2017. Photo: GRDC

TEST RESULT: Steve Marcroft says results from recent blackleg screenings of canola cultivars have been factored into the updated disease ratings for 2017. Photo: GRDC

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GRAINGROWERS are urged to check the latest blackleg disease ratings for canola cultivars ahead of seeding.

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GRAINGROWERS are urged to check the latest blackleg disease ratings for canola cultivars ahead of seeding.

The ratings, contained in the GRDC Blackleg Management Guide, have been revised following the confirmation of reduced resistance in some Group A canola cultivars.

With increased demand for canola seed leading to a shortage of some commercial seed supplies, it is imperative that growers planning to instead use seed retained from last year’s crops know if their retained seed is from a cultivar classified as having increased susceptibility to blackleg.

Marcroft Grains Pathology principal Steve Marcroft says results from the latest blackleg screenings of canola cultivars, undertaken as part of the GRDC-funded National Canola Pathology Project, have been factored into the updated disease ratings for 2017.

“Those screenings have confirmed that the resistance status of some Group A cultivars has changed and growers must be aware of these new ratings before they sow this year’s canola crops,” he said.

“If open-pollinated cultivars were grown in 2016 and growers plan to sow seed retained from these crops this year, it is vital they check the 2017 blackleg ratings.

“For example, ATR Bonito and ATR Wahoo previously each had a moderately-resistant rating, but that has fallen to moderately susceptible.

“An MS cultivar may not be suitable for medium to higher rainfall zones if not protected.

“When sowing retained MS cultivars in higher rainfall zones, growers should protect seed with Jockey and Impact In-Furrow fungicides and budget for a foliar fungicide to apply if required.”

Dr Marcroft warns that the risk of blackleg in 2017 will be increased due to the larger forecast canola area, but the actual disease severity will also be dependent on seasonal conditions.    

Blackleg has caused up to 90 per cent yield loss in trials.

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