Many viruses cause diseases with mosaic-type symp- toms in crop and horticultural plants. In the United States, these mosaic diseases commonly appear on beans, pep- pers, potatoes, roses, tobacco, and tomatoes. Although the disease doesn’t kill rose plants, effects of infection reduce vigor, shorten lifespan, stunt growth, and weaken the plant so it cannot survive the stress of transplantation or winter injury. Cause Several viruses cause mosaic disease symptoms in roses—Prunus necrotic ringspot virus (PNRSV), apple mosaic virus (ApMV), and Arabis mosaic virus (ArMV). ese viruses can affect roses separately or in some combi- nation, a trait known as a virus complex. Rose mosaic virus complex (RMVc) is oſten a more accurate designation than the more common name rose mosaic virus (RMV) because it takes into account that several viruses are present in the plant and causing the disease symptoms. Mosaic disease caused by RMVc is one of the most widespread rose diseases in the United States and occurs with many rose varieties. Symptoms Rose mosaic disease appears in the spring, usually only on a portion of the plant (Fig. 1). It is easy to miss or mistake symptoms because they show up early in the sea- son on the first sets of new growth and become obscured by subsequent growth. Typical symptoms are ring spots, chlorotic line patterns (Fig. 2), watermarking (Fig. 3), and leaf mottling. Yellow net and yellow mosaic patterns can also develop. Infection by the PNRSV virus can cause leaf mottling. Vein banding, oſten seen in roses infected with both EPLP-027 1/17 Rose Mosaic Virus Kevin Ong, Associate Professor and Extension Plant Pathologist Madalyn Shires, Extension Graduate Student, Department of Plant Pathology and Microbiology* * Texas A&M AgriLife Extension Service, e Texas A&M University System Figure 1. Mosaic symptoms typical of rose mosaic virus complex. The mosaic appears first on older leaves of the plant and, as the disease progresses, on the new growth. Source: Jennifer Olsen, Oklahoma State University, Bugwood.org. PNRSV and ArMV, can occur with PNRSV-only infec- tions, especially during long periods of high temperatures. In some cultivars, RMVc causes a color-breaking, mottled effect in flowers. Disease Movement A typical mode of disease transmission is through graſting diseased tissue or buds onto diseased rootstock. is disease is unlikely to spread via contaminated prun- ing tools, insect vectors, or plant-to-plant irritation (plants rubbing against each other).