Soybean aphid biology

The soybean aphid was first reported in Iowa in 2000. It has survived the winter and colonies are now being found south of Decorah in Winneshiek County in northeastern Iowa. Aphid colonies were very small, often less than 10 aphids on a plant, and they were clustered on the underside of the newly developing trifoliate leaves. The aphids were difficult to find and checking 20 plants at random in several fields was not a large enough sample to detect these small population