Vegetative period
Stages before flowering (V stages)

Fungicide applications are not recommended in the early vegetative growth stages for soybean rust control. Applying a fungicide just prior to soybean flowering (R1) may be prudent if disease risk is high. This is especially true for late-planted crops and/or very late-maturing varieties that may develop a large canopy before flowering.
 
Flowering through seed fill
R1 (beginning of flowering) through R5 (beginning seed)

Soybean rust develops most rapidly during soybean reproductive growth stages. The first fungicide application should be made before rust appears or shortly after the onset of disease. When rust incidence is very low, each infected leaflet may have only one or very few pustules, and the disease is difficult to detect. An application of a fungicide when the level of disease is more noticeable may protect newly emerging leaves, but may not result in a yield benefit. If other foliar and/or stem diseases are present with rust, then some adjustment of fungicide mix may be needed. Sometimes, multiple applications may be needed, depending upon at what growth stage the disease is first detected and subsequent environmental conditions. Consecutive applications of stand-alone strobilurin or triazole fungicides should not be made, due to the concern of fungicide resistance developing in the soybean rust pathogen as well as possible label restrictions.
 
Full seed to maturity
R6 (full seed) to R8 (full maturity)

The economic benefits of applying a fungicide at late growth stages are uncertain. In addition, many fungicides have preharvest interval restrictions that do not allow applications past R5 or R6. Fungicide labels should be read carefully for specific directions and restrictions.