2018 ASHS Annual Conference

Rose rosette disease is caused by the Rose Rosette Virus (Emaravirus) and transmitted by the eriophyid mite Phyllocoptes fructiphilus. Since 2015, the Combating Rose Rosette Disease SCRI project has been evaluating a wide range of rose germplasm for its resistance to RRD in replicated plots in Tennessee, Delaware, Oklahoma, and Texas. In addition, observational data was collected from a number of gardens. Thus far, about 900 rose accessions have been observed. Of these 900 accessions, 850 have developed typical symptoms of RRD although most have not been tested to verify that the virus is present in the plant. The first replicated trials were planted in Tennessee and Delaware and contained 227 unique rose accessions with 68% planted at both sites. The disease pressure in these sites was augmented by attaching symptomatic shoots with mites from infected plants to the test plants. After 2 years in the field, there are still 34 rose accessions that have not yet shown symptoms nor have been detected with the virus. This includes 12 garden roses, 7 rugosa hybrids, 8 Rosa species accessions, and 8 selections from the TAMU breeding program. These will be tested for one more season to confirm their resistance to the disease.