Soybean aphid populations continue to build, although somewhat slowly, across the state. I scouted three blooming soybean fields in Ames on July 8 and 80 to 100 percent of the plants had aphids. Populations averaged 15 aphids per plant with the high population being 125 per plant. Brian Lang, Iowa State University Extension field specialist-crops, notes that in northeastern Iowa near Decorah, aphid numbers are still behind last season's and still below what we anticipate as a threshold (an average of >100 aphids per plant).