Previous research at Iowa State indicates that within the field, soybean varieties with the Rag1 gene have lower densities of soybean aphids compared to a susceptible isolines. However, this resistance did not keep the aphid population below the economic injury level, despite having populations that were significantly reduced. Yield losses of 30-50% were reported compared to the aphid-free plots. The use of aphid resistant varieties will require changes in aphid control management recommendations. This project will address some of these concerns.