Occurrence and Distribution of Aphis glycines on Soybeans in Illinois in 2000 and Its Potential Control

During August of the 2000 growing season, Aphis glycines Matsumura, an aphid native to Asia, was found colonizing soybean plants in Illinois (Fig. 1) (1,2). Hundreds of aphids were observed on every leaflet on plants in some fields in northern Illinois. Within 3 weeks of the initial observation, A. glycines was found at lower population densities in most central and southern Illinois locations including the southernmost county in the state (Fig. 2). While conducting the aphid survey in Illinois, aphids were collected from about half the counties in the state. These collections will be used for molecular typing and virus transmission studies. By the end of the 2000 season, A. glycines was found in most states in the midwest, and coincidentally, it was reported for the first time in Australia (3). Fig. 1. Aphis glycines colonies on a soybean leaf.