Rose Rosette disease: the menace of the rose world

The rose is a highly diverse multispecies polyploid complex which is one of the most important woody ornamental crops in the world. Rose Rosette Disease has emerged over the last 50 years as the most damaging virus disease of rose in the United States and potentially the world. Although first reported in the 1940s, it was not until 2011 when the causal virus was identified as the negative-sense RNA Emaravirus rosae. This virus and its Phyllocoptes eriophyid mite vectors have a host range restricted to Rosa. As all major rose cultivars are susceptible to this disease, infected plants can be asymptomatic for extended periods, and the vector is very small, the movement of the disease appears common within commercial channels especially before diagnostic tests for RRV were developed in the 2010s. The best management practices include pathogen and vector exclusion with virus-tested propagative material collections and quarantine procedures and the field management of virus and mite levels and dispersal using chemical and cultural approaches. Host plant resistance is only found at low levels among the major commercial rose cultivars. Given the value of RRD-resistant roses, current work emphasizes accelerating the breeding process via an improved understanding of genetic interactions of the virus-mite-rose host complex and improved phenotyping and molecular breeding approaches.