A. Rose Rosette: The Early Years by Ann Peck

Reprinted from the May 2001 Heritage Rose Quarterly Rose Letter

Diseases start somewhere but are recorded only after someone notices that something is wrong. The disease we now call Rose Rosette dates back to 1940s when it was called "witches' broom of roses" after similar growths of the same name on brambles and other plants.

Illogically it appeared not in one garden, but in two years at two sites (one a garden, the other a plant research center) 635miles (1,022 Km) apart. In 1940, witches' broom was reported from the Morden Research Center in Morden Manitoba as "Witches' Broom (?virus) was observed affecting some canes at Morden, Man.; the number of spines was greatly increased on affected canes." This innocuous two line report in the Twentieth Annual Report of the Canadian Plant Disease Survey for 1940 corresponded to a time when the Canadian Department of Agriculture was working on the development of cold hardy roses.

Only in 1953 did the disease reappear in the literature. Two scientists with the Department of Plant Pathology at Berkley CA reported on a rose that had been sent to them in 1941 from the State Training School at Lander WY. (Thomas and Scott, 1953) The rose was not a cultivated rose, but 'Rosa rubrifolia' which had been grown as an ornamental. The following year a second bush was sent from Lander to Berkley, but this time it was "an unidentified native rose" with similar symptoms. The disease persisted in the vicinity of Lander at least until 1945 according to the 1953 report. One of the Berkley scientists collected a plant with similar symptoms from Trinity County, CA, mountains, and tentatively identified the rose as 'Rosa pisocarpa'.

Because of California's rose industry, there was apparently considerable worry about the susceptibility of the root stock used by industry to the potentially destructive disease. Graft innoculation tests were run with both the Wyoming and California strains of the disease on the more commonly used rootstocks. Neither 'Rosa californica' nor 'Rosa spinosissima' showed symptoms of the Wyoming disease after graft innoculations although 'Rosa multiflora', 'Rosa nutkana', 'Rosa odorata', 'Rosa rubrifolia', and 'Belle Portugal' and 'Rockin Robin' all developed symptoms. (Symptoms took 3 to 14 months to develop.)

The California strain did not affect 'R. californica', 'R. pisocarpa' or 'R. multiflora'. The 'California' strain did infect 'R. nutkana', 'R. odorata', and 'Ragged Robin'. (Our in-rose-club plant pathologist mentioned that innoculation test results are a test of the positive, when a graft takes and transmits the disease in question, but a less effective test of the negative. Negative transmisibility may not be a reproducible result in the hands of a more skilled scientist, using different examples of the same cultivars (Dr. Mark Windham, 2000, pers.com).

Time passed and nobody noticed the disease; it was just studied in California. From 1945 to 1957, there are no records of witches' broom on roses. A report in the AMERICAN ROSE, 1961 featured the next appearance of the disease, still called "Witches' Broom." Glenn Viehmeyer from North Platte Nebraska first saw the disease in 1957 and reported it to be identical to the disease that he personally had observed at Morden (implying that the disease continued at Morden at least until 1957, how else

could Weihmeyer compare his findings?) He watched it until it became "epidemic in the rose breeding program at the North Platte Experiment Station in 1960". He reported the destruction of "about an acre of roses to gain some semblance of control". There was an additional two mile long fence of 'R. multiflora' near the State Fish Hatchery that was found to be infected and subsequently destroyed. An added infestation was found one hundred fifty miles south east of North Platte, again in 'R. multiflora'. (There was a major program to use 'R. multiflora' for soil stabiliaztion, hedging, erosion control, and land reclamation as well as for wildlife cover. Plants were sold in bundles of a hundred whips. I know someone who thought he had ordered 9,000 whips and received 90,000. He planted all of them on a farm near Nashville TN.)

Veihmeyer reported that the disease did not appear to be fatal to 'R. Arkansana' or to 'R. Woodsii'. In his trial gardens he found it on "Climbers, hybrid teas, floribundas, and several of the ‘old fashioned ‘ roses as well as "R. arkansana', 'R. canina', 'R. corymbifera', 'R. eglanteria', 'R. Hugonis', 'R. montezumae', 'R. multiflora', 'R. pomifera', 'R. rubrifolia', and 'R. woodsii'. " He reported the disease "not visually evident" on 'R. spinosissima' although hybrids with 'R. Spinosissima' in their germplasm tended to exhibit increased thorniness. (Veihmeyer, 1961, p100)

Only in a subsequent paper did the extent of the problem in Morden appear. Allington et al, (1968, p. 1139) listed roses that Viehmeyer had seen: "species or cultivars..apparently infected with rose rosette at both Morden and North Platte "Hybrids of 'R. eglanteria', Hybrids with 'R. multiflora', and Cultivars of hybrid teas, floribundas, and grandifloras". Then there was nothing, no reports, no followup although Viehmeyer wrote he was doing additional transmission tests, but retired in the mid 60's and died in the early 70's.

The clouds of history then closed in again until 1978. Results of an outbreak that began in 1978 in Kansas and Missouri and spread in 1982 to Arkansas and Oklahoma are featured in a report which documents the spread into urban areas. It also mentions a fence of 'R. multiflora' 40 miles long that had been planted 15-20 years earlier. Originally 211,000 whips of multiflora were planted and had multiplied making an even more dense hedge. An estimated 90-95% of the plants were infected and or had died. (Crowe 1982,1983)

This would appear to be good news for the eradication of the multiflora, now characterized as an invasive alien species. Clifty Falls State Park in Madison Indiana had massive rose rosette infections in 1989-1992 with 97% of the studied plants being sick.(Amrine, et al. 1989). We went to Clifty Falls in November of 2000 and there is still abundant 'R. multiflora' in that park, so it appears that rose rosette causes sick roses, but they or their descendents remain sources of infection.

Witches' Broom, now called "rose rosette disease", was not a disease of 'Rosa multiflora' in its initial appearances in North America. It moved into fences of 'R. multiflora' because there were thousands of roses living in proximity to other species roses that were infected with the disease. It took advantage of a man-made situation, and it continues to spread..

References Cited:

Allington, W.B., Staples, R., and Viehmeyer, G., 1968, Transmission of Rose Rosette Virus by the Eriophyid Mite Phyllocoptes fructiphilus, Jour. Econ. Entomol. 61(5): 1137-1140.

Amrine, J.W., Hindal, D.F., Appel, J., Stasny, T. and Kasser, A., 1989, Rose Rosette as Biocontrol of Multiflora Rose 1987-1989: 316-319.

Conners, I.L., 1940, Twentieth Annual Report of the Canadian Plant Disease Survey 1940, Dominion of Canada,Department of Agriculture, Science Service, Division of Botny and Plant Pathology, p.98.

Crowe, F.J., 1982, A recent Outbreak of Withces' Broom of Rose in Eastern Kansas and Western Missouri, Phytopathology 72(7): 976-977. (Abst.)

Crowe, F.J., 1983, Witches' Broom of Rose: A New Outbreak in Several Central States, Plant Disease, 67(5):544-546

Secor, G.A., Kong, M, and Nyland, G. 1977. Rose virus and virus-like diseases. California Agriculture, March:4-7.

Thomas, E.A., Scott, C.E., 1953. Rosette of Rose. Phytopathology 43: 218-219.

Viehmeyer, G. 1962. A "new" disease of Roses. American Rose Annual:98-101.

B. Canada has had RRD Before
By Ann Brooke Reaugh Peck, Reprinted from National Roses Canada - abbreviated

In the middle of the twentieth century, diseases were often named after their symptoms (powdery mildew and black spot). The reports below use the term mosaic virus to refer to leaves with two colours when the colour boundaries are sharply defined. (This is not the same as Rosa Mosaic Viruses that are such a problem in roses produced in some US growing fields. In RMV, the patterns are dependent on which virus (or viruses) affects the plant. RMV does not cause aberrant growth that is often excessive and unexpected. RMV does weaken roses’ resistance to cold temperatures but does not distort growth.) In RRD, the mosaic pattern follows the veins of the leaves and is often reddish-purple-vein clearing in pattern.

From the Canadian Plant Disease Surveys, published by the Dominion of Canada, Department of Agriculture, Science Service, from the years 1940 through 1945, compiled by L. L. Conners, we have the first records of the disease now called Rose Rosette.

1940: “Witches’ broom (?virus) was observed affecting some canes at Morden, Man.; the number of spines was greatly increased on affected canes.’ (Page 98)

    1941: “Mosaic (virus) was destructive to some bushes at Morden, Man.’ it was first noted at Morden in 1940when it was reported as Witches’ Broom (P.D.S. 20:98) (W.L. Gordon) Mosaic affected a single bush of Else Poulsen at St. Catharines, Ont.; this mosaic was a very definite vein-banding type. (G.C. Chamberlain)” (page 98)

    1943: “Mosaic (virus) affected odd plants of Rosa spp. At Morden Man.; it is destructive and is spreading. (W.L. Gordon)” (page 115)

    1944: “Mosaic (virus) caused considerable damage to some plants at Morden and severely injured a bush at Stonewall, Man. (W.L. Gordon) A single plant of Kirsten Poulson (Hybrid polyantha) in Lincoln Col. Ont., showed foliage mottling and a distinct breaking of the flower colour.: (G. C. Chamberlain)” (page 116)

    1945: “Following were affected by mosic at the Central Experiment Farm, Ottawa: Dorothy Perkins, Langdon, Maagraf, Philadelphia Rambler, Tuscany and an unnamed seedling (H.N. Racicot)” (page 121)

    1948 “Mosaic (virus) Three bushes of Kirsten Poulsen were infected in a bed at St. Catharines, Ont. Onley one plant was infected in 1945. (G.C. Chamberlain) A single plant of Purity climber at the C.D.f. Ottawa was mottled and severely distoreted and bore no bloom; a single normal shoot from the endge of the clump, apparently originating from the bleo the graft indicated that the rootstock was either uninfected or was an symptomles carrier. One plant of R.. Gallica var. Tuscany aso showed severe mottling and distortion; many blooms had failed to open normally. (D.B.O. Saville)”

    There are references beyond the Canadian Plant Disease Surveys.

    1946: “The original plant of Carmenetta (R. rubifolia x. R. rugosa) grew into a large bush which was very effective with its cluster of bright red flowers and its purplsih green foliage but in recent years has been attacked by a virus disease and has had to be destroyed. A grafted plant seems to be free up to the present and two sister seedling also appear to be healthy.’ Isabella Preston 1946. “Progress in breeding hardy roses” The American Rose Annual p.51.

    1954: “Witches’ Broom Disease This is a virus disease spread by insects, the criminal being a leaf hopper. The trouble so far as I have been able to learn is mostly confined to the Western Prairies and well attack any varieties of roses to which the virus is transferred. Since methods of dealing with the viruses are still in the infant stage, the only remedy is to remove any plants showing infection including any wild ones in the vicinity.”( Fillmore, R.A. 1953, Roses for Canadian Gardens, Ryerson Press, Toronto, p. 128. ) (The same words were used by Mr. Fillmore in the 1959 edition.)