Only two virus diseases are currently recognized as infecting sweet corn in New York. They are maize dwarf mosaic virus (MDMV) and maize white line mosaic virus (MWLMY). MDMV has been present in the state since the late 1960s; MWLMY was first recognized in the United States in Tompkins County, New York, in 1979. These two diseases differ greatly in their method of transmission and their locations within the state.