Recently, EPA approved a master Section 3 label (as of 03/24/2008) for Proline Fungicide from Bayer Crop Science for use in soybean against soybean rust (Phakopsora pachyrhizi) and powdery mildew (Microsphaera diffusa). To legally use Proline on soybean, growers will need to have in their possession the existing container label as well as the supplemental label that Bayer Crop Science is allowed to market. This stipulation about having both the existing and supplemental label will continue until a fully labeled product container is available. The active ingredient for Proline is prothioconazole and this is in the group 3 fungicide class (DMI fungicides). The DMI fungicides inhibit one specific enzyme, C14-demthylase, which plays a role in sterol production (Mueller and Bradley 2008). The recommended rate for Proline is 2.5 to 3.0 fluid ounces per acre and it is recommended to use Proline as either a preventative spray or at first visible symptom of disease. Finally, some restrictions for the use of Proline include a 21-day preharvest interval and to not use this product for more than three applications per season or more than 9 fluid ounces per acre per use season.

 

Reference:

 

Mueller, D. S., and Bradley, C. A. 2008. Field Crop Fungicides for the North Central United States. NC-IPM Center, USDA-CSREES.