Like all vegetatively propagated plants, roses are subject to infection by virus and virus-like diseases that spread during propagating operations. Studies by plant pathologists with the California Department of Food and Agriculture have shown a 14 percent loss in salable blooms of virus-diseased greenhouse roses. Similar losses occur in landscape roses. Diseased plants tend to be less vigorous and less likely to survive than healthy plants, and diseases often detract from the aesthetic quality of the plant.