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‘R. multiflora’ & Rose Rosette Disease
The Good, The Bad, The Ugly
The
White
Menace
This Program Services Committee
presentation created by:
Mary Peterson
Master Rosarian
‘R. multiflora’
Plants of ‘R. multiflora’
Fields overgrown with ‘R. multiflora’
Flower clusters of ‘R. multiflora’
Photo by John Lynch
Panicles of ‘R. multiflora’ flowers
Photo by James Miller
‘Achenes’ or rose seeds of ’R. multiflora’
Northern Mockingbird and Multiflora Rose HipsPhoto by Johann Schumacher
Distribution of ‘R. multiflora‘(green areas = areas of ‘R. multiflora’)
(white areas = none reported)
Photo by S. Debolt
‘R. multiflora’ infected with Rose Rosette
“Witches Broom”
Photo by James W. Amrine Jr.
Photo by M.A. Hansen
Photo by Ann Peck
Abiotic damage to foliage from RoundUp®
Photos by Baldo VillegasEntomology Dept. UC Davis
Photo by M.A. Hansen
Photos by Ann Peck
Reddish aberrant new growth on modern roses infected with RRD
Photo by Chris Evans
Typical Rose Rosette growth on ‘R. multiflora’ roses
Distorted bud formation on a modern rose infected with RRD
Photo by S. Debolt
Photo by James W. Amrine Jr.
Typical Red New Growth of RRD Infected plant
Twisted stem growth on RRD infected plant
Symptomatic thorns on roses caused by rose rosette
Photo by S. Debolt
Photo by Jim Yearwood
Mowing and burning operation
Physical Control of stands
of ‘R. multiflora’
Rose bushes cut with a chain saw
during the winter months
After spending approximately 2 months cutting Multiflora rose bushes, burning them was very
satisfying
Eriophyid Mites
Biological Control of RRD
Microscopic Eriophyid Mites
Phyllocoptes fructiphilus Keifer Phyllocoptes fructiphilus Keifer
Phyllocoptes fructiphilus Keifer
Rose Stem Girdler
Photo by Whitney Cranshaw Girdled cane caused by larva Photos by James W. Amrine Jr.
A "flag" caused by the break of a
cane at the girdle
Close up of girdle and broken cane
Agrilus aurichalceus
(Coleoptera: Buprestidae)
Rose Seed Chalcid Wasp
• Photo by James W. Amrine Jr.
Rose Seed Chalcid
Rose hips damaged by Chalcid wasp
Cold Weather Affect on New Rose Growth
Spring Dwarf Disease?
‘R. multiflora’ and RRD
• Early Identification of RRD infected ‘R. multiflora’
• Physical Control – cutting/burning• Herbicide/Chemical – Round Up,
Krenite,
Banvel• Biological Control – Eriophyid Mite
Rose Seed Chalcid
Rose Stem Girdler
What The Future Holds…The reduced populations of multiflora rose remaining after the
RRD epidemic are likely to be infested by the seed chalcid at the same rate (90-95%) as plants in Korea and Japan. Multiflora rose will then be another occasional plant in the environment, and not the noxious weed that it is today. It is estimated that this scenario will transpire within the next three to five decades. Farmers and others wanting eradication of multiflora rose desire human intervention to increase the rate of spread of the disease, the mite and the torymid into uninfested areas. However, many rosarians desire that all augmentation work with RRD and the mite cease.
The rose seed chalcid could be intentionally released in areas wherever infestation rates are below 50-60%. Risk to other rose species from this seed chalcid appears to be minimal. Even if not deliberately spread, its range will increase by birds. Eventually, multiflora rose will be reduced to low levels, occurrence of RRD will become minimal and problems for farmers and rosarians alike should be greatly reduced.
Dr. Keith Zary (VP of research for Jackson & Perkins) has encouraged breeders to concentrate their efforts on hybridizing roses that are RRD resistant and RRD tolerant. A species called the McCartney rose, which exists as a weed in Texas, is susceptible to RRD but resistant to feeding by the mites that transmit the disease. It may be possible, through breeding techniques, to incorporate this mite resistance into cultivated roses in the future. In the meantime, it would be wise to assume that all cultivated roses are potentially susceptible to the disease and to be on the lookout for symptoms of rose rosette.
Additional Considerations…
Program Services Committee
John Mattia, Chairman Jolene Adams
Richard DonovanPat Hibbard
Larry Peterson Mary PetersonDiane Schrift
Program Services
Power Point programs on roses are available for download from the ARS website, ‘members only section.’
They are offered to our members for use by a local or district rose society or an ARS judging or consulting rosarian school.
These programs are copyright © ARS 2007
Commercial use is strictly forbidden.
The End