Emergence of Cladosporium macrocarpum disease in canola (Brassica napus)

Authors

Alexander Idnurm, University of Melbourne
Ciara Beard, Department of Primary Industries and Regional Development, Western AustraliaFollow
Anne Smith, Department of Primary Industries and Regional Development, Western AustraliaFollow
Andrea Hills, Department of Primary Industries and Regional Development, Western AustraliaFollow
Kylie Chambers, Department of Primary Industries and Regional Development, Western AustraliaFollow

Document Type

Article

Publication Date

10-8-2021

Journal Title

Australasian Plant Pathology

ISSN

ISSN: 0815-3191, eISSN: 1448-6032

Keywords

Cladosporium brassicae, Fungicide resistance, Rapeseed, Upper canopy infection

Disciplines

Agricultural Science | Agronomy and Crop Sciences | Biosecurity

Abstract

New disease symptoms were observed on canola (Brassica napus) crops late in the 2019 and 2020 growing seasons in Western Australia. Cladosporium macrocarpum was isolated from infected material, and the fungus responsible for the symptoms was demonstrated by fulfilling Koch’s postulates. One strain exhibited relatively high tolerance to prothioconazole and tebuconazole fungicides compared to other canola pathogens Sclerotinia sclerotiorum and Leptosphaeria maculans. In a 2019 field trial in a commercial canola crop, symptom incidence caused by Cladosporium was only significantly reduced by a double application of a foliar fungicide (active ingredients prothioconazole and tebuconazole) registered in canola for other diseases, while single applications gave no significant response. This new disease, caused by a ubiquitous fungal species, may be a consequence of changes to farm management strategies to reduce other fungal diseases of canola.

Recommended Citation

Idnurm, A., Beard, C., Smith, A. et al. Emergence of Cladosporium macrocarpum disease in canola (Brassica napus). Australasian Plant Pathol. 50, 687–694 (2021). https://doi.org/10.1007/s13313-021-00819-8