An overview of the ergot (Claviceps purpurea) issue in western Canada: challenges and solutions

Ergot, caused by the ascomycete fungus Claviceps purpurea (Fr.) Tul., has been described to occur since the Middle Ages, but more recently has become a significant issue on the Canadian prairies. In 1999, there was an outbreak of ergot where 12% of all Canadian Western Red Spring (CWRS) and 4% of Canadian Western Amber Durum (CWAD) wheat samples delivered to elevators were infested with ergot sclerotia. A similar outbreak occurred in Manitoba in 2005, followed by outbreaks in 2008 and 2011 in all three Prairie provinces. In 2008, 12-15% of all CWRS samples were infested with ergot, while in 2011, these levels rose to 15-29% of all CWRS samples. In CWAD wheat, 15% of samples were infested in Saskatchewan in 2008 and 14% in 2011. Management practices that may influence ergot severity include crop rotation, management and nutrition, seeding practices, pesticide applications, nature of the crop (i.e. autumn vs. spring crop and self-pollinated vs. cross-pollinated host species), and harvest and postharvest management. Recently, research has been conducted on host resistance and avoidance of infection, although problems in assessing host resistance and variability among pathogen strains have been encountered. Unfortunately, none of these control measures has been found to be entirely successful in controlling ergot on their own. As a consequence, producers should always approach ergot management as an integrated process with strategies that target all components of the disease triangle. Although ergot outbreaks can be sporadic in nature, sustained research funding is necessary to support research that leads to the development of more effective strategies for ergot management.