Trials were conducted at three Iowa locations (Sutherland, Ames and Nashua) over three years (2008 to 2010) to determine the effects of applications of insecticides (Asana ®, Leverage 2.7SE™) and fungicides (Stratego® YLD) applied alone or combined (i.e. a tank mix) at soybean growth stages R1 (beginning flowering) and R3 (beginning pod set) on soybean aphid populations and soybean yield in Iowa. Because these pesticides were applied based on plant growth stage, regardless of the level of fungal disease or insect pressure, these treatments are referred to as prophylactic treatments. We compared the prophylactic approaches to an integrated pest management (IPM) approach, in which an insecticide (Asana) was applied when soybean aphids reached an economic threshold of 250 aphids per plant.