Identification & Incidence: The soybean aphid is a small, yellow aphid with distinct black tailpipes, or cornicles, on the abdomen. The adult aphid is the size of a small potato leafhopper nymph. Adults lay live young rather than eggs. Early in the season the aphids will be found on the upper leaves. As populations increase, they can be found on the upper stems and later on the lower leaves.
Sampling: Sample 10 plants in 5 areas of the field and make an estimate of the number of aphids found on the plants.
Economic Threshold: Economic thresholds have not been developed for the soybean aphid at this time. It is thought that it will take thousands per plant to be economically significant.
Management Options: There are several predators, including lady beetles, that may help take care of soybean aphid. If populations continue to build, even with lady beetles, then the use of an insecticide may be needed.