The prevalence of diseases caused by plant viruses on processing beans in WI has dramatically changed during the past two years. We normally observe symptoms of virus diseases affecting processing beans along field edges and where there are concentrated areas of perennial legumes. On numerous occasions in recent years when teaching field courses I’ve found it difficult to find even a single plant with virus-like symptoms in production fields. All this began to change in 2000 when I was called to visit several fields in eastern WI where an unusually high proportion of the plants exhibited symptoms of virus infection. In the first field I visited near Oostburg, WI, over a third of the plants exhibited virus-like symptoms that included plant stunting, mosaic patterns on the foliage and discolored pods. Symptoms were uniformly distributed across the field instead of just along the perimeter. Subsequent samples from the eastern shore area of WI and from the Cambria area indicated a fairly wide distribution of virus-infected plants in several fields. These plants also exhibited a wide range of symptoms typical of virus infection. During 2001 the geographical area of processing beans affected by virus problems increased substantially. In addition to the eastern areas of WI along Lake Michigan and fields in the Cambria area, symptoms were observed in southern WI and into the Central Sands area. There were also reports of virus problems on processing beans grown in southern MI, southern Ontario and western NY. Samples of snap beans sent to us from fields near Buffalo, NY exhibited symptoms similar to the symptoms observed in WI.