During the 2000 and 2001 growing season, the development and presence of virus symptoms in snap bean increased dramatically. The symptoms were primarily caused by cucumber mosaic virus and alfalfa mosaic virus. The viruses had large economic impacts by reducing yields 90% or more and causing off colored, deformed and generally poor quality beans. These viruses have been present in various weeds and crops within WI for a number of years, but were seldom seen within snap bean and never to the extent seen in 2000 or 2001. The recent invasion and establishment of the soybean aphid in the Midwestern and Eastern U.S. has been directly linked to the increased incidence of the viruses in snap bean. The midsummer migration of the soybean aphid into snap bean vectored viruses at high levels and subsequently led to the unprecedented yield and quality losses.