AS WINTER crop sowing gets underway, canola growers and advisers have been seeking advice on what to do to best manage the disease blackleg, particularly around whether to apply foliar fungicides early in the season.
Marcroft Grains Pathology’s Steve Marcroft 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,” he said.
Dr Marcroft 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,” he 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.”
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 will be on Wednesday, March 31, from 11.30am-12 noon AEST (8.30-9am AWST). To register, go to http://bit.ly/3rVjgQR