The main disease controlled by fungicide in dry beans is white mould (Sclerotinia sclerotiorum). White mould has a wide host range, infecting other broadleaf crops such as canola, soybeans and sunflowers.
Foliar fungicides for suppression or control of white mould are preventative, meaning they must be applied before disease symptoms are visible. The R2/early pin bean stage is the best time to apply fungicide for effective white mould control. This stage coincides with flowering (100% of plants with an open blossom) and early pod development (first pin-pods are 0.5 to 1″ long).
If warm, humid conditions persist throughout flowering and pod development, consider a second fungicide application 7 to 14 days later.
The Fungicide Decision Worksheet for Managing White Mould in Dry Beans (also available in the Bean App) was created to help determine the risk of white mould disease development, based on environmental and agronomic factors.
More information can be found at
Foliar Fungicide Decision Making in Dry Beans – Manitoba Pulse & Soybean Growers
Follow along as we show you screen shots of how to use the Bean App, in three easy steps, and the information it will be asking for. You don’t need to be in the field to complete this assessment. It is better to be in your office where you can access weather data and crop rotation history.
Remember we want to do this assessment when the dry bean plants have about four trifoliates, so that we can be ready ahead of when the crop is in full flower and properly staged for the application.
Open the Bean App and click on White Mould Risk Assessment
Step 1 ( has three sections): From the drop down menus make choices that best describe the Weather Conditions Experienced Prior to Flowering
Step 2 (has two sections): From the drop down menus make choices that best describe the Weather Expected During Flowering
Step 3 (has five sections): From the drop down menus make choices that best describe the Management Factors applicable to the field
The Bean App will tally up your score, if you score above 30 then a fungicide application is recommended. A score of between 20-30 suggests a fungicide application can be considered. With a score of less than 20, a fungicide application is not recommended.
