• Faba Beans
• Agriculture and Agri-Food Canada
• Disease Management

Objective

To assess incidence and severity of chocolate spot and other foliar diseases on faba bean in Saskatchewan and Alberta. To determine conditions leading to Botrytis spore release and infection in the field. To evaluate conditions for chocolate spot disease development in controlled studies.

Outcome

Surveys for foliar diseases of commercial faba bean fields in Saskatchewan and Alberta were completed in 2017, 2018 and 2019. All faba bean crops surveyed had foliar lesions in all years, but disease severity was low across all fields. Botrytis species that cause chocolate spot were commonly present but inflict higher disease severity in wet years. Furthermore, Stemphylium blight was common, sometimes more so than chocolate spot, and it’s etiology and impact on yield need further study. Results of field spore trapping, and experiments to determine the optimum inoculum concentration revealed that disease development, or progression of an infection to disease symptoms, is more heavily dependent on environmental conditions, and particularly cool night-time temperatures and dew periods. These environmental conditions should be considered as risk factors for chocolate spot development and fungicide timing, as this project showed that disease inoculum is always present.

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