Tillage is necessary for reducing the amount of crop residue available that may be hosting the fungus.
If infection is severe enough, foliar fungicides can be used to gain control of the fungus. With infections that happen later in the season during pod fill, strobilurin or triazole class fungicides may be used to avoid premature defoliation. Application of fungicides is not highly recommended since economic returns often are not comparable due to such a low yield loss rate from brown spot infection. Please contact your local plant pathologist to learn what is most effective in your area and how to use it best. Always read and follow all label instructions.
Planting continuous soybeans creates an environment very conducive to the growth and production of this fungus. Rotation with non-legumes is a good way to avoid infection. There are few, if any, resistant varieties. Planting varieties that mature more quickly can be a good way to avoid risk of disease.