Soybean aphid population dynamics are influenced by a number of factors, most notably the “top down” effects of natural enemies (predators, parasitoids, and pathogenic fungi) and the “bottom up” effects of the host soybean plant. As for the latter, host plant effects can include things such as plant stage or maturity, and plant nutritional status. For example, plant nitrogen has been found to be an important factor in cotton aphid growth and reproduction on cotton plants (Nevo and Coll, 2001). In the case of the soybean aphid, following the 2000 discovery of this pest in Wisconsin, entomologists and agronomists noticed that infestations in soybean seemed to be more severe in potassium deficient fields.
Soil Science Extension
University of Wisconsin Madison