Improving Sclerotinia disease control in edible beans and canola

The Challenge

Sclerotinia disease continues to be a production constraint to many crops in Alberta. Initial research has potentially found two new effective management tools, but more research is required to confidently support them.

The Project

Determine if there is a benefit between micronutrient and Sclerotinia fungicide combinations on bean and canola for white mold and stem rot management.

The Results

In vitro, Fluazinam (1.67mg/mL) + CuSO4 combination showed to be the most effective with a log reduction of 3.64. Heads Up® was the best at reducing white mold in dry bean for 3 out of 8 site years and had the highest seed yield for dry bean in 5 out of 8 years. Acibenzolar-S-methyl and β-Aminobutanoic acids were best at reducing stem rot on canola and β-Aminobutanoic acid had the highest yields in 4 out of 8 site years. Fluazinam activity was the most responsive to the addition of micronutrient and was greatly enhanced in its ability to reduce S. sclerotiorum biofilms. Additionally, if the field contained a Sclerotinia-tolerant variety, the severity of sclerotinia was consistently reduced. However, these plots did not consistently produce higher yields.

Grower Benefits

If sclerotinia is a constant hinderance on successful canola production, Sclerotinia-tolerant varieties consistently delivered on reducing the amount of disease present. Losses from disease must be compared to the potential yield loss of the Sclerotinia-tolerant varieties. Tank mixing a micronutrient (CuSO4, AgNO3 or ZnSO4) with a fungicide (fluazinam or cyprodinil) can improve fungicide efficacy by 1%. Although the increase is small, this control of white mold would provide over $2 million in canola yield savings annually.