Canola growers are being encouraged to assess the extent of blackleg disease in crops this spring to reduce the risk of disease next year and beyond.
To support growers in determining current disease levels, the Grains Research and Development Corporation has released the 2017 Spring Blackleg Management Guide Fact Sheet, developed by the National Canola Pathology Project team.
The fact sheet outlines specific steps to manage blackleg. It includes cultivar blackleg ratings and resistance groups for all canola cultivars, including new cultivars which will be available in 2018.
The resource can help growers assess if they are in a high-risk situation and guide them to minimise future yield losses.
Blackleg is a sexually reproducing pathogen that will overcome cultivar resistance genes and is more severe in areas of intensive canola production.
Oilseeds disease authority Steve Marcroft, of Marcroft Grains Pathology, said that to assess disease levels in current crops, samples could be taken any time from the end of flowering to windrowing (swathing).
‘‘Pull 60 randomly chosen stalks out of the ground, cut off the roots with a pair of secateurs and, using reference photos in the GRDC fact sheet, estimate the amount of disease in the stem cross-section,’’ Dr Marcroft said.
‘‘Yield loss commonly occurs when more than 50 per cent of the cross-section of the cut stem is discoloured.’’
Dr Marcroft said if growers identified they were in a high-risk situation, they should use management practices outlined in the fact sheet to reduce blackleg severity for coming seasons.
■Find the fact sheet at: https://grdc.com.au/GRDC-FS-BlacklegManagementGuide