Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2001
Publication Date: N/A
Interpretive Summary: During August of the 2000 growing season, Aphis glycines, an aphid native to Asia, was found colonizing soybean plants in Illinois. This is the first report of this aphid in Illinois. Hundreds of aphids were observed on every leaflet on plants in some fields in northern Illinois. A survey was conducted to determine the extent of the invasion. 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. The aphid has a complex life cycle involving two hosts. Sexual stages deposit eggs for overwintering on the primary host, buckthorn. In the spring, winged aphids fly from buckthorn in search of soybean fields. On soybean plants, the aphid produces both wingless and winged adults, the latter contributing to geographic spread of the aphid. In the fall, winged individuals move back to buckthorn. Both winged adults and eggs were observed on buckthorn in the fall of 2000. Many viruses present in the U.S. have the potential to be transmitted by A. glycines including a Soybean mosaic virus (SMV), one of the most common soybean viruses in Illinois. Further studies are underway to determine if different strains of SMV, as well as other soybean-infecting aphid transmitted viruses, can be transmitted by A. glycines. This report will provide the ground work for further research being planned to study the basic biology of the aphid including monitoring its movement, the impact it has on yields, its importance as a vector of soybean viruses, and potential management strategies.
Technical Abstract: During August of the 2000 growing season, Aphis glycines Matsumura, an aphid native to Asia, was found colonizing soybean plants in Illinois. Hundreds of aphids were observed on every leaflet on plants in some fields in northern Illinois. While conducting the aphid survey in Illinois, aphids were collected from about half the counties in the state. In temperate regions, A. glycines has a complex life cycle involving two hosts. Sexual stages deposit eggs for overwintering on the primary host, Rhamnus spp. (buckthorn). In the spring, winged aphids fly from Rhamnus in search of soybean fields. In the fall, winged individuals move back to Rhamnus. Both winged adults and eggs were observed on R. cathartica in the fall of 2000. Because A. glycines had not been previously documented in the U.S., no insecticides are registered in the U.S. for its control. An insecticide efficacy trial was established in a soybean field in Carroll County (northwestern Illinois) on August 26, 2000. At the start of the trial, there was an average of 45 aphids counted per leaflet. Treatments of Dimethoate, Lannate, Lorsban, Penncap-M, and Warrior (0.025 lb a.i./acre) decreased aphids densities by more than 90% at 3 DAT.