Since 2000, soybean aphid has been the primary soybean insect pest in Iowa. Infestations are sporadic and unpredictable, but this insect has the ability to cause significant yield loss during periods of optimal reproduction. Several notable infestations have been reported, particularly in north-central Iowa, this week, and therefore scouting to determine population densities is strongly encouraged. Fields that have a fairly uniform infestation with low densities (e.g., 50% of plants infested with an average of 40 aphids per plant) should be closely monitored in August.