Transmission of the rose rosette disease agent to Rosa multiflora by Phyllocoptes fructiphilus (Acari: Eriophyidae)

Tests proved that rose rosette disease (RRD) results from a pathogenic agent and is not a mite-induced response of multiflora rose. Graft transmission of the RRD agent to rooted cuttings of Rose multiflora required 45 to 80 days and was only 46% successful. Graft transmission to large vigorously growing transplants was more rapid (30-60 days) and 100% successful. Graft transmission showed the agent resides in roots of multiflora rose. Laboratory transmission of RRD by the eriophyid mite, Phyllocoptes fructiphilus (Acari: Eriophyidae) to transplants in 1986 was 92.3% and symptoms appeared in 17-24 days. Transmission of RRD by mites to rooted cuttings was unsuccessful. In 1987, the rate of field transmission with P. fructiphilus was 12.5% and lab transmission was 20% with symptoms appearing in 30-279 days and 29-47 days respectively. Reduced laboratory transmission in 1987 was thought to be drought-induced. Attempts to transmit RRD with Tetranychus urticae (Acari: Tetranychidae) were unsuccessful.