Since the soybean aphids\u27 arrival in Iowa, many growers have observed that soybean aphid outbreaks vary across different varieties of soybeans. As mentioned in earlier articles within this special edition, several factors can influence soybean aphid population growth (plant health, predators, overwintering success). Adding to the factors that influence aphid population growth is variation in soybean aphid response to different varieties of soybeans, but the source of this variation is unclear. Typically, external features like leaf hairs or internal factors that contribute to aphid feeding (antibiosis) can influence how well an aphid population grows on a given plant
