White mold is a fungal disease that can cause significant damage to soybean crops. It is most effective to apply fungicides to soybeans from the R1 growth stage (one open flower on 50% of the plants) through the R3 growth stage (one pod 3/16 inches on the top four fully developed leaf nodes on the main stem). After the R3 growth stage, fungicides are less effective and may not be worth the cost.
If fields are exhibiting visible white mold symptoms, it is too late to apply fungicide. Fungicides can only prevent white mold, not cure it. If the plants in infested fields have not yet reached the R4 growth stage, a fungicide application may be beneficial if most of the plants in the field are not showing signs of infection and conditions are predicted to favor disease development.
To determine if it is too late to apply a fungicide, soybean producers should consider the following factors:
• The growth stage of the soybeans
• The severity of the white mold infestation
• The cost of the fungicide
• The potential benefits of the fungicide
If you are unsure whether or not it is too late to apply a fungicide, you should contact your local extension agent for advice.
Tips for managing white mold in soybeans:
• Plant resistant varieties of soybeans.
• Avoid planting soybeans in fields with a history of white mold.
• Rotate soybeans with non-legume crops.
• Control weeds and insects that can weaken soybean plants and make them more susceptible to white mold.
Apply fungicides preventively, from the R1 growth stage through the R3 growth stage.
By following these tips, you can help to protect your soybean crop from white mold and minimize yield losses.
For more information on Crop Diseases, visit our sister site Farms.com Field Guide pages: https://www.farms.com/field-guide/crop-diseases/
Photo Credit: istock-oticki
Categories: Michigan, Crops, Soybeans