Emerging diseases affecting quinoa (Chenopodium quinoa) cultivation in Saskatchewan, Canada

Quinoa (Chenopodium quinoa) is a relatively new crop in Canada and is gaining interest among producers. To close critical knowledge gaps and support plant health in quinoa production, comprehensive disease surveys were conducted during the 2021 and 2022 growing seasons across 11 commercial fields representative of most of the quinoa production areas in Saskatchewan. Disease incidence was assessed at 10 sites per field along W-shaped transects, with infected plants destructively sampled and analysed in the laboratory. Five major diseases were identified: downy mildew, leaf spots, stem diseases, panicle rot and seedling disease. A total of 206 fungal isolates were recovered, with Fusarium species being the most prevalent (37.4%). Fusarium graminearum and F. avenaceum were consistently associated with panicle rot symptoms. Alternaria alternata and Stemphylium vesicarium accounted for 18.4% and 12.1% of isolates, respectively, and were linked to leaf spot symptoms. Sclerotinia sclerotiorum was primarily associated with stem rot. Seedling diseases and root rots were predominantly caused by F. redolens, F. culmorum and Rhizoctonia solani. Koch’s postulates were fulfilled, confirming these pathogens as causal agents of diseases observed in the field. This study establishes a critical baseline for quinoa disease research in Canada, highlighting the need for ongoing monitoring and research to develop adaptive management strategies. Such efforts are essential to mitigate disease impacts and ensure the long-term sustainability of quinoa production in Canada and beyond.