Management of Rose Rosette Disease

That Rose Bush is Not Your Grandchild

Rose Rosette Disease (RRD) (Fig. 1A) is caused by the virus Rose Rosette Virus (RRV). The virus is spread by an eriophyid mite (Fig. 1B). The mite is blind (no eyes) and flightless (no wings), however it can float in the air like dust particles. This may sound inefficient, but the virus is spread efficiently from one rose to another. Mite populations may be 40–70 times higher on symptomatic roses than on healthy ones, which leads to likely virus movement to nearby roses.

Though some areas of the country are not seriously impacted by RRD, the virus and mites can be moved anywhere in the country on infected, asymptomatic plants.

Early Detection is Critical

Know what early symptoms of RRD look like:

  • One or more shoots (not low ones like basal breaks) may be red

  • Thickened stems

  • Unusually more or enlarged thorns (prickles)

  • Leaflets are unusually thin (Fig. 1C)

Do not wait for rosettes to form (Fig. 1D). Inspect roses at least monthly.

Take Action

If multiple symptoms are found, REMOVE THE BUSH!
It’s better to protect your garden by removing a prize-winning bush that you mistakenly thought had RRD than to be slow to remove a RRV-infected rose.
A rose is just a bush (I know—blasphemy), not a grandchild – cull it!

To dispose:

  • Cut the bush into pieces

  • Tie it in a black plastic bag

  • Bake in the sun for several days before composting

Treatment Option

The only miticide labeled for homeowners that is known to reduce eriophyid mite populations is bifenthrin. If using miticides:

  • Begin spraying 2 weeks after first bloom flush

  • Spray every 3 weeks until killing frost

Note: Resistance is known but not currently available.

A Setback in Research – But You Can Help

Storm clouds on the horizon: Due to shifting national priorities, USDA NIFA has announced that they are no longer accepting applications for RRD research proposals—for the indefinite future. This will likely slow the development of RRD-resistant roses.

If you want to financially support the continued development of RRD-resistant roses, please contact:

Become a part of the team supporting this vital research!

About the Author: Mark Windham was a distinguished professor of ornamental pathology at the University of Tennessee, Knoxville. After retirement, Mark and his wife Karen love to walk beaches, visit with old rose friends, and enjoy grandchildren.