Tobamoviruses—tobacco mosaic virus (TMV), tomato mosaic virus (ToMV) and pepper mild mottle virus (PMMV) — are stable and highly infectious viruses that are very easily spread from plant to plant by contact. These viruses can survive for long periods in crop debris and on contaminated equipment. Although these viruses affect field crops, they are more often a problem in greenhouse crops where plants are generally grown at a higher density and handled more frequently.