Rose viruses are common in garden roses and are easily transmitted by propagation. Several viruses are found worldwide, including Prunus necrotic ringspot virus (PNRSV), Apple Mosaic Virus (ApMV), and Rose spring dwarf-associated virus (RSDaV). For the rose hobbyist, the problems caused by common rose viruses can include unsightly foliage, decreased vigor, and smaller and/or fewer flowers. The problems caused by virus are even more serious for professional rose growers and nurseries. For cut flower producers, there may be a significant decrease in the production or quality of the blooms, depending on the rose variety and the type of virus(es). Nursery plant producers may face rejection of interstate shipments and eventual destruction of large numbers of unsalable plants. Rose nurseries cannot afford to have the quality of their product compromised by virus infection.
Most recently the viral causal agent of Rose Rosette Disease (RRD) was described. RRD has been known since the 1940s, but no causal agent could be identified. Ioannis Tzanetakis at the University of Arkansas, using modern technology, found a novel plant virus, Rose rosette virus (RRV), to be the causal agent. RRD has emerged as a major threat for U.S. rose growers, landscapers and consumers east of the Rockies. It now threatens to decimate the U.S. rose industry. RRV is transmitted by a wind-blown eriophyid mite (Phyllocoptes fructiphilus). RRD has devastated roses in several key botanical gardens and other large public and private gardens. Unlike other rose diseases, RRD can result in death of rose plantings within two to three years of infection. The garden rose industry understands that the effects of these viruses can be significant to the success of the commercial rose nursery business and the adoption of disease resistant, healthy roses in sustainable garden sites.
There are a number of viruses that have, so far, only been reported in Europe, Africa, Australia, and New Zealand. Scientists and regulators in the U.S. are working hard to keep these agents at bay, to prevent severe symptoms such as fissure, curly head, little leaf, rose bud proliferation, and rose flower break from entering domestic nursery stock.
For additional information on rose viruses and graft-transmissible diseases, please click here to view our outreach materials.