All landscape roses are believed to be susceptible to RRD. A combination of the following strategies is highly recommended to control eriophyid mite populations and the transmission of RRD. There is no cure once a plant is infected.
Rose gardeners, homeowners and nurseries can help slow the spread of RRD by reporting its occurrence here.
When transplanting new roses, carefully inspect plants for signs and symptoms of eriophyid mite activity and RRD, and regularly inspect them througout the growing season for symptoms of RRD. Any plant displaying symptoms of infection should be removed and disposed of immediately, including its roots. Any plants with suspected infection should be quarantined from healthy plants and monitored for continued symptoms.
Pruning can be used to remove the eriophyid mite, which tends to hide near buds and leaf scars. "Dead-heading" roses throughout the season may prove effective, but will be more effective with the subsequent application of horticultural oils to control any remaining mites.
It is extremely important to not only remove but dispose of infected plant material because it can possibly infect nearby healthy plants (Figure 1). So any roots, leaves and other parts of infected plants should be cleared from an area before installing new, healthy plants. A leaf blower is not recommended for removing such debris, as it may blow mites onto healthy plants; instead, debris should be removed by hand, placed in a sealed bag and disposed of off-site. It is also recommended that you wait 1 to 2 months after removing infected plants before transplanting healthy ones.
Any wild multiflora rose plants in the vicinity of rose gardens or nurseries should be removed. Cultivated roses should not be planted on hilltops or downwind of any known multiflora rose growth. Rose plants should also be well-spaced so that stems and leaves do not touch each other, which helps prevent eriophyid mite movement from plant to plant. Mixed plantings (roses with non-rose plants) are preferable to monocultures (all roses).
Maintain health and vigor of rose plants by watering during periods of drought, testing soils and applying fertilizer as needed, as well as controlling other diseases and insect pests.
Miticides can be utilized to help control the eriophyid mite. However, those miticides known to control spider mites do not necessarily control eriophyid mites that transmit RRD, and mites may develop resistance to such chemicals. Some miticides that are registered for controling both eriophyid and spider mites include:
It is strongly recommended that you use these chemicals according to label instructions, and exercise caution when applying, to prevent poisoning and drift (Figure 2).
Predatory mites (Acari: Phytoseiidae) show promise for controlling eriophyid mite populations and developing RRD- and/or mite-resistant varieties of rose, but further studies are required.