Upper canopy blackleg infection in canola is prevalent across WA
- WA grainbelt
Plant pathologist Ravjit Khangura (DPIRD) reports that blackleg upper canopy infection has been very common in many canola crops across the WA grainbelt this season.
The blackleg fungus is capable of attacking all the aerial parts of the plant throughout the growing season.
Upper canopy infection (UCI) is the new term for infection of above ground plant parts including flower bud, flower, pod, stem and branch.
Occasionally the entire flowering head is colonised by the fungus causing it to droop and shrivel.
Although infection of the crown is the most damaging phase of the disease, infection of the upper canopy can sometimes leads to severe yield losses due to pre-mature ripening and shattering of pods.
Symptoms of UCI include the presence of abundant pycnidia in affected plant parts. Lesions on the stems and branches are usually elongated with a dark margin and white centre with pycnidia.
UCI is more frequently observed in canola varieties that have low to moderate resistance to blackleg and particularly in varieties with group C resistance and/or varieties that have recently downgraded for resistance to blackleg. It has been found to be more severe in crops that are sown under tight canola rotations.
Currently, no control measures are recommended for managing UCI but research is in progress in WA and eastern Australia under the GRDC funded National Canola Pathology project (UM00051) to investigate various strategies for controlling the upper canopy blackleg infection.
More information on managing blackleg in crops is available at DPIRD’s BlacklegCM app page and GRDC’s Blackleg Management Guide (2018 spring variety ratings).
For more information contact Ravjit Khangura, Plant pathologist, South Perth on +61 (0)8 9368 3374.